YAMAUCHI Shigeo

Natural sciences, Theoretical studies related to particle-, nuclear-, cosmic ray and astro-physics

Natural sciences, Astronomy

May 2009, 奈良女子大学理学部教授

Apr. 2007, Apr. 2009, 岩手大学准教授 人文社会科学部専任担当

Apr. 1997, Mar. 2007, 岩手大学人文社会科学部助教授

Oct. 1993, Mar. 1997, 岩手大学人文社会科学部講師

Apr. 1993, Sep. 1993, 理化学研究所基礎科学特別研究員

Apr. 1991, Mar. 1993, 日本学術振興会特別研究員PD

Apr. 1987, Mar. 1991, 名古屋大学大学院, 理学研究科宇宙理学専攻

Apr. 1983, Mar. 1987, Nagoya University, 理学部物理学科

日本天文学会

International Astronomical Union

高エネルギー宇宙物理連絡会

日本物理学会

Refereed, Publications of the Astronomical Society of Japan, Oxford University Press (OUP), Characterization of diffuse X-ray emission from IGR J17448$-$3232: an implication of a line-of-sight merging activity, Shoko Watanabe; Shigeo Yamauchi; Kumiko K Nobukawa; Hiroki Akamatsu, The results of spectral analysis for the galaxy cluster IGR J17448$-$3232 are presented. The intracluster medium (ICM) in the central region ($r\lt 300^{\prime \prime }$, $320\:$kpc) has a high electron temperature plasma of $kT_{\rm e} \sim 13$–$15\:$keV, and an ionization temperature estimated from an intensity ratio of Fe xxvi Ly$\alpha /$Fe xxv He$\alpha$ lines is lower than the electron temperature, which suggests that the ICM is in the non-ionization equilibrium (NEI) state. The spectrum in the central region can be also fitted with a two-component model: a two-temperature plasma model in a collisional ionization equilibrium (CIE) with temperatures of $7.9\:$keV and $\gt 34\:$keV, or a CIE$+$power-law model with a temperature of $9.4\:$keV and a photon index of 1.1. The two-component models can represent the intensity ratio of Fe xxvi Ly$\alpha /$Fe xxv He$\alpha$ lines. On the other hand, the spectrum in the outer region ($r\gt 300^{\prime \prime }$) can be explained by a single CIE plasma model with a temperature of 5–$8\:$keV. Based on the spectral feature and its circular structure, we propose that the NEI plasma was produced by merging along the line-of-sight direction., 30 Oct. 2019, 71, Scientific journal, 10.1093/pasj/psz098

Refereed, Publications of the Astronomical Society of Japan, Oxford University Press (OUP), Neutral iron line in the supernova remnant IC 443 and implications for MeV cosmic rays, Kumiko K Nobukawa; Arisa Hirayama; Aika Shimaguchi; Yutaka Fujita; Masayoshi Nobukawa; Shigeo Yamauchi, We report a discovery of bright blob-like enhancements of an Fe i K$\alpha$ line in the northwest and the middle of the supernova remnant (SNR) IC 443. The distribution of the line emission is associated with molecular clouds interacting with the shock front, and is totally different from that of the plasma. The Fe i K$\alpha$ line has a large equivalent width. The most plausible scenario for the origin of the line emission is that the MeV protons accelerated in the shell leak into the molecular clouds and ionized the Fe atoms therein. The observed Fe i K$\alpha$ line intensity is consistent with the prediction of a theoretical model in which MeV protons are accelerated along with GeV and TeV protons at the SNR., 01 Dec. 2019, 71, 6, Scientific journal, 10.1093/pasj/psz099

Refereed, Publications of the Astronomical Society of Japan, Oxford University Press (OUP), X-ray spectra of Sagittarius A East and diffuse X-ray background near the Galactic center, Akiko Ono; Hideki Uchiyama; Shigeo Yamauchi; Masayoshi Nobukawa; Kumiko K Nobukawa; Katsuji Koyama, 01 Jun. 2019, 71, 3, Scientific journal, 10.1093/pasj/psz025

Refereed, Publications of the Astronomical Society of Japan, Oxford University Press (OUP), New scenario of plasma evolution in IC 443, Arisa Hirayama; Shigeo Yamauchi; Kumiko K Nobukawa; Masayoshi Nobukawa; Katsuji Koyama, 01 Apr. 2019, 71, 2, Scientific journal, 10.1093/pasj/psy153

Refereed, Journal of Physics: Conf. Series, Measurement of Low-Energy Cosmic Rays via the Neutral Iron Line, Nobukawa; K. K; Saji, S; Hirayama, A; Nobukawa, M; Yamauchi, S; Matsumoto, H; Koyama, K, Feb. 2019, 1181, 012040

Refereed, Publications of the Astronomical Society of Japan, Oxford University Press (OUP), Detection of polarized gamma-ray emission from the Crab nebula with the Hitomi Soft Gamma-ray Detector†, Felix Aharonian; Hiroki Akamatsu; Fumie Akimoto; Steven W Allen; Lorella Angelini; Marc Audard; Hisamitsu Awaki; Magnus Axelsson; Aya Bamba; Marshall W Bautz; Roger Blandford; Laura W Brenneman; Gregory V Brown; Esra Bulbul; Edward M Cackett; Maria Chernyakova; Meng P Chiao; Paolo S Coppi; Elisa Costantini; Jelle de Plaa; Cor P de Vries; Jan-Willem den Herder; Chris Done; Tadayasu Dotani; Ken Ebisawa; Megan E Eckart; Teruaki Enoto; Yuichiro Ezoe; Andrew C Fabian; Carlo Ferrigno; Adam R Foster; Ryuichi Fujimoto; Yasushi Fukazawa; Akihiro Furuzawa; Massimiliano Galeazzi; Luigi C Gallo; Poshak Gandhi; Margherita Giustini; Andrea Goldwurm; Liyi Gu; Matteo Guainazzi; Yoshito Haba; Kouichi Hagino; Kenji Hamaguchi; Ilana M Harrus; Isamu Hatsukade; Katsuhiro Hayashi; Takayuki Hayashi; Kiyoshi Hayashida; Junko S Hiraga; Ann Hornschemeier; Akio Hoshino; John P Hughes; Yuto Ichinohe; Ryo Iizuka; Hajime Inoue; Yoshiyuki Inoue; Manabu Ishida; Kumi Ishikawa; Yoshitaka Ishisaki; Masachika Iwai; Jelle Kaastra; Tim Kallman; Tsuneyoshi Kamae; Jun Kataoka; Satoru Katsuda; Nobuyuki Kawai; Richard L Kelley; Caroline A Kilbourne; Takao Kitaguchi; Shunji Kitamoto; Tetsu Kitayama; Takayoshi Kohmura; Motohide Kokubun; Katsuji Koyama; Shu Koyama; Peter Kretschmar; Hans A Krimm; Aya Kubota; Hideyo Kunieda; Philippe Laurent; Shiu-Hang Lee; Maurice A Leutenegger; Olivier Limousin; Michael Loewenstein; Knox S Long; David Lumb; Greg Madejski; Yoshitomo Maeda; Daniel Maier; Kazuo Makishima; Maxim Markevitch; Hironori Matsumoto; Kyoko Matsushita; Dan McCammon; Brian R McNamara; Missagh Mehdipour; Eric D Miller; Jon M Miller; Shin Mineshige; Kazuhisa Mitsuda; Ikuyuki Mitsuishi; Takuya Miyazawa; Tsunefumi Mizuno; Hideyuki Mori; Koji Mori; Koji Mukai; Hiroshi Murakami; Richard F Mushotzky; Takao Nakagawa; Hiroshi Nakajima; Takeshi Nakamori; Shinya Nakashima; Kazuhiro Nakazawa; Kumiko K Nobukawa; Masayoshi Nobukawa; Hirofumi Noda; Hirokazu Odaka; Takaya Ohashi; Masanori Ohno; Takashi Okajima; Naomi Ota; Masanobu Ozaki; Frits Paerels; Stéphane Paltani; Robert Petre; Ciro Pinto; Frederick S Porter; Katja Pottschmidt; Christopher S Reynolds; Samar Safi-Harb; Shinya Saito; Kazuhiro Sakai; Toru Sasaki; Goro Sato; Kosuke Sato; Rie Sato; Makoto Sawada; Norbert Schartel; Peter J Serlemtsos; Hiromi Seta; Megumi Shidatsu; Aurora Simionescu; Randall K Smith; Yang Soong; Łukasz Stawarz; Yasuharu Sugawara; Satoshi Sugita; Andrew Szymkowiak; Hiroyasu Tajima; Hiromitsu Takahashi; Tadayuki Takahashi; Shin’ichiro Takeda; Yoh Takei; Toru Tamagawa; Takayuki Tamura; Takaaki Tanaka; Yasuo Tanaka; Yasuyuki T Tanaka; Makoto S Tashiro; Yuzuru Tawara; Yukikatsu Terada; Yuichi Terashima; Francesco Tombesi; Hiroshi Tomida; Yohko Tsuboi; Masahiro Tsujimoto; Hiroshi Tsunemi; Takeshi Go Tsuru; Hiroyuki Uchida; Hideki Uchiyama; Yasunobu Uchiyama; Shutaro Ueda; Yoshihiro Ueda; Shin’ichiro Uno; C Megan Urry; Eugenio Ursino; Shin Watanabe; Norbert Werner; Dan R Wilkins; Brian J Williams; Shinya Yamada; Hiroya Yamaguchi; Kazutaka Yamaoka; Noriko Y Yamasaki; Makoto Yamauchi; Shigeo Yamauchi; Tahir Yaqoob; Yoichi Yatsu; Daisuke Yonetoku; Irina Zhuravleva; Abderahmen Zoghbi; Yuusuke Uchida, We present the results from the Hitomi Soft Gamma-ray Detector (SGD) observation of the Crab nebula. The main part of SGD is a Compton camera, which in addition to being a spectrometer, is capable of measuring polarization of gamma-ray photons. The Crab nebula is one of the brightest X-ray / gamma-ray sources on the sky, and, the only source from which polarized X-ray photons have been detected. SGD observed the Crab nebula during the initial test observation phase of Hitomi. We performed the data analysis of the SGD observation, the SGD background estimation and the SGD Monte Carlo simulations, and, successfully detected polarized gamma-ray emission from the Crab nebula with only about 5 ks exposure time. The obtained polarization fraction of the phase-integrated Crab emission (sum of pulsar and nebula emissions) is (22.1% +/- 10.6%), and, the polarization angle is 110.degrees 7 + 13.degrees 2 /-13.degrees 0 in the energy range of 60-160 keV (The errors correspond to the 1 sigma deviation). The confidence level of the polarization detection was 99.3%. The polarization angle measured by SGD is about one sigma deviation with the projected spin axis of the pulsar, 124.degrees 0 +/- 0.degrees 1., 01 Dec. 2018, 70, 6, Scientific journal, 10.1093/pasj/psy118

Refereed, Publications of the Astronomical Society of Japan, Oxford University Press (OUP), Origin of the low-temperature plasma in the Galactic center X-ray emission, Shigeo Yamauchi; Miku Shimizu; Masayoshi Nobukawa; Kumiko K Nobukawa; Hideki Uchiyama; Katsuji Koyama, 01 Aug. 2018, 70, 4, Scientific journal, 10.1093/pasj/psy077

Refereed, Publications of the Astronomical Society of Japan, Oxford University Press (OUP), Hitomi X-ray observation of the pulsar wind nebula G21.5−0.9, Felix Aharonian; Hiroki Akamatsu; Fumie Akimoto; Steven W Allen; Lorella Angelini; Marc Audard; Hisamitsu Awaki; Magnus Axelsson; Aya Bamba; Marshall W Bautz; Roger Blandford; Laura W Brenneman; Gregory V Brown; Esra Bulbul; Edward M Cackett; Maria Chernyakova; Meng P Chiao; Paolo S Coppi; Elisa Costantini; Jelle de Plaa; Cor P de Vries; Jan-Willem den Herder; Chris Done; Tadayasu Dotani; Ken Ebisawa; Megan E Eckart; Teruaki Enoto; Yuichiro Ezoe; Andrew C Fabian; Carlo Ferrigno; Adam R Foster; Ryuichi Fujimoto; Yasushi Fukazawa; Akihiro Furuzawa; Massimiliano Galeazzi; Luigi C Gallo; Poshak Gandhi; Margherita Giustini; Andrea Goldwurm; Liyi Gu; Matteo Guainazzi; Yoshito Haba; Kouichi Hagino; Kenji Hamaguchi; Ilana M Harrus; Isamu Hatsukade; Katsuhiro Hayashi; Takayuki Hayashi; Kiyoshi Hayashida; Junko S Hiraga; Ann Hornschemeier; Akio Hoshino; John P Hughes; Yuto Ichinohe; Ryo Iizuka; Hajime Inoue; Yoshiyuki Inoue; Manabu Ishida; Kumi Ishikawa; Yoshitaka Ishisaki; Masachika Iwai; Jelle Kaastra; Tim Kallman; Tsuneyoshi Kamae; Jun Kataoka; Satoru Katsuda; Nobuyuki Kawai; Richard L Kelley; Caroline A Kilbourne; Takao Kitaguchi; Shunji Kitamoto; Tetsu Kitayama; Takayoshi Kohmura; Motohide Kokubun; Katsuji Koyama; Shu Koyama; Peter Kretschmar; Hans A Krimm; Aya Kubota; Hideyo Kunieda; Philippe Laurent; Shiu-Hang Lee; Maurice A Leutenegger; Olivier Limousin; Michael Loewenstein; Knox S Long; David Lumb; Greg Madejski; Yoshitomo Maeda; Daniel Maier; Kazuo Makishima; Maxim Markevitch; Hironori Matsumoto; Kyoko Matsushita; Dan McCammon; Brian R McNamara; Missagh Mehdipour; Eric D Miller; Jon M Miller; Shin Mineshige; Kazuhisa Mitsuda; Ikuyuki Mitsuishi; Takuya Miyazawa; Tsunefumi Mizuno; Hideyuki Mori; Koji Mori; Koji Mukai; Hiroshi Murakami; Richard F Mushotzky; Takao Nakagawa; Hiroshi Nakajima; Takeshi Nakamori; Shinya Nakashima; Kazuhiro Nakazawa; Kumiko K Nobukawa; Masayoshi Nobukawa; Hirofumi Noda; Hirokazu Odaka; Takaya Ohashi; Masanori Ohno; Takashi Okajima; Naomi Ota; Masanobu Ozaki; Frits Paerels; Stéphane Paltani; Robert Petre; Ciro Pinto; Frederick S Porter; Katja Pottschmidt; Christopher S Reynolds; Samar Safi-Harb; Shinya Saito; Kazuhiro Sakai; Toru Sasaki; Goro Sato; Kosuke Sato; Rie Sato; Makoto Sawada; Norbert Schartel; Peter J Serlemtsos; Hiromi Seta; Megumi Shidatsu; Aurora Simionescu; Randall K Smith; Yang Soong; Łukasz Stawarz; Yasuharu Sugawara; Satoshi Sugita; Andrew Szymkowiak; Hiroyasu Tajima; Hiromitsu Takahashi; Tadayuki Takahashi; Shin’ichiro Takeda; Yoh Takei; Toru Tamagawa; Takayuki Tamura; Takaaki Tanaka; Yasuo Tanaka; Yasuyuki T Tanaka; Makoto S Tashiro; Yuzuru Tawara; Yukikatsu Terada; Yuichi Terashima; Francesco Tombesi; Hiroshi Tomida; Yohko Tsuboi; Masahiro Tsujimoto; Hiroshi Tsunemi; Takeshi Go Tsuru; Hiroyuki Uchida; Hideki Uchiyama; Yasunobu Uchiyama; Shutaro Ueda; Yoshihiro Ueda; Shin’ichiro Uno; C Megan Urry; Eugenio Ursino; Shin Watanabe; Norbert Werner; Dan R Wilkins; Brian J Williams; Shinya Yamada; Hiroya Yamaguchi; Kazutaka Yamaoka; Noriko Y Yamasaki; Makoto Yamauchi; Shigeo Yamauchi; Tahir Yaqoob; Yoichi Yatsu; Daisuke Yonetoku; Irina Zhuravleva; Abderahmen Zoghbi; Toshiki Sato; Nozomu Nakaniwa; Hiroaki Murakami; Benson Guest, We present results from the Hitomi X-ray observation of a young composite-type supernova remnant (SNR) G21.5-0.9, whose emission is dominated by the pulsar wind nebula (PWN) contribution. The X-ray spectra in the 0.8-80 keV range obtained with the Soft X-ray Spectrometer (SXS), Soft X-ray Imager, and Hard X-ray Imager (HXI) show a significant break in the continuum as previously found with the NuSTAR observation. After taking into account all known emissions from the SNR other than the PWN itself, we find that the Hitomi spectra can be fitted with a broken power law with photon indices of Gamma(1) = 1.74 +/- 0.02 and Gamma(2) = 2.14 +/- 0.01 below and above the break at 7.1 +/- 0.3 keV, which is significantly lower than the NuSTAR result (similar to 9.0 keV). The spectral break cannot be reproduced by time-dependent particle injection one-zone spectral energy distribution models, which strongly indicates that a more complex emission model is needed, as suggested by recent theoretical models. We also search for narrow emission or absorption lines with the SXS, and perform a timing analysis of PSR J1833-1034 with the HXI and the Soft Gamma-ray Detector. No significant pulsation is found from the pulsar. However, unexpectedly, narrow absorption line features are detected in the SXS data at 4.2345 keV and 9.296 keV with a significance of 3.65 sigma. While the origin of these features is not understood, their mere detection opens up a new field of research and was only possible with the high resolution, sensitivity, and ability to measure extended sources provided by an X-ray microcalorimeter., 01 Jun. 2018, 70, 3, Scientific journal, 10.1093/pasj/psy027

Refereed, Journal of Astronomical Telescopes, Instruments, and Systems, SPIE-Intl Soc Optical Eng, Hitomi (ASTRO-H) X-ray Astronomy Satellite, Tadayuki Takahashi; Motohide Kokubun; Kazuhisa Mitsuda; Richard L. Kelley; Takaya Ohashi; Felix Aharonian; Hiroki Akamatsu; Fumie Akimoto; Steven W. Allen; Naohisa Anabuki; Lorella Angelini; Keith Arnaud; Makoto Asai; Marc Audard; Hisamitsu Awaki; Magnus Axelsson; Philipp Azzarello; Chris Baluta; Aya Bamba; Nobutaka Bando; Marshall W. Bautz; Thomas Bialas; Roger Blandford; Kevin Boyce; Laura W. Brenneman; Gregory V. Brown; Esra Bulbul; Edward M. Cackett; Edgar Canavan; Maria Chernyakova, 13 Mar. 2018, 4, 02, 1, 1, Scientific journal, 10.1117/1.jatis.4.2.021402

Refereed, Publications of the Astronomical Society of Japan, Oxford University Press (OUP), Atmospheric gas dynamics in the Perseus cluster observed with Hitomi*, Felix Aharonian; Hiroki Akamatsu; Fumie Akimoto; Steven W Allen; Lorella Angelini; Marc Audard; Hisamitsu Awaki; Magnus Axelsson; Aya Bamba; Marshall W Bautz; Roger Blandford; Laura W Brenneman; Gregory V Brown; Esra Bulbul; Edward M Cackett; Rebecca E A Canning; Maria Chernyakova; Meng P Chiao; Paolo S Coppi; Elisa Costantini; Jelle de Plaa; Cor P de Vries; Jan-Willem den Herder; Chris Done; Tadayasu Dotani; Ken Ebisawa; Megan E Eckart; Teruaki Enoto; Yuichiro Ezoe; Andrew C Fabian; Carlo Ferrigno; Adam R Foster; Ryuichi Fujimoto; Yasushi Fukazawa; Akihiro Furuzawa; Massimiliano Galeazzi; Luigi C Gallo; Poshak Gandhi; Margherita Giustini; Andrea Goldwurm; Liyi Gu; Matteo Guainazzi; Yoshito Haba; Kouichi Hagino; Kenji Hamaguchi; Ilana M Harrus; Isamu Hatsukade; Katsuhiro Hayashi; Takayuki Hayashi; Tasuku Hayashi; Kiyoshi Hayashida; Junko S Hiraga; Ann Hornschemeier; Akio Hoshino; John P Hughes; Yuto Ichinohe; Ryo Iizuka; Hajime Inoue; Shota Inoue; Yoshiyuki Inoue; Manabu Ishida; Kumi Ishikawa; Yoshitaka Ishisaki; Masachika Iwai; Jelle Kaastra; Tim Kallman; Tsuneyoshi Kamae; Jun Kataoka; Satoru Katsuda; Nobuyuki Kawai; Richard L Kelley; Caroline A Kilbourne; Takao Kitaguchi; Shunji Kitamoto; Tetsu Kitayama; Takayoshi Kohmura; Motohide Kokubun; Katsuji Koyama; Shu Koyama; Peter Kretschmar; Hans A Krimm; Aya Kubota; Hideyo Kunieda; Philippe Laurent; Shiu-Hang Lee; Maurice A Leutenegger; Olivier Limousin; Michael Loewenstein; Knox S Long; David Lumb; Greg Madejski; Yoshitomo Maeda; Daniel Maier; Kazuo Makishima; Maxim Markevitch; Hironori Matsumoto; Kyoko Matsushita; Dan McCammon; Brian R McNamara; Missagh Mehdipour; Eric D Miller; Jon M Miller; Shin Mineshige; Kazuhisa Mitsuda; Ikuyuki Mitsuishi; Takuya Miyazawa; Tsunefumi Mizuno; Hideyuki Mori; Koji Mori; Koji Mukai; Hiroshi Murakami; Richard F Mushotzky; Takao Nakagawa; Hiroshi Nakajima; Takeshi Nakamori; Shinya Nakashima; Kazuhiro Nakazawa; Kumiko K Nobukawa; Masayoshi Nobukawa; Hirofumi Noda; Hirokazu Odaka; Takaya Ohashi; Masanori Ohno; Takashi Okajima; Naomi Ota; Masanobu Ozaki; Frits Paerels; Stéphane Paltani; Robert Petre; Ciro Pinto; Frederick S Porter; Katja Pottschmidt; Christopher S Reynolds; Samar Safi-Harb; Shinya Saito; Kazuhiro Sakai; Toru Sasaki; Goro Sato; Kosuke Sato; Rie Sato; Makoto Sawada; Norbert Schartel; Peter J Serlemtsos; Hiromi Seta; Megumi Shidatsu; Aurora Simionescu; Randall K Smith; Yang Soong; Łukasz Stawarz; Yasuharu Sugawara; Satoshi Sugita; Andrew Szymkowiak; Hiroyasu Tajima; Hiromitsu Takahashi; Tadayuki Takahashi; Shin’ichiro Takeda; Yoh Takei; Toru Tamagawa; Takayuki Tamura; Keigo Tanaka; Takaaki Tanaka; Yasuo Tanaka; Yasuyuki T Tanaka; Makoto S Tashiro; Yuzuru Tawara; Yukikatsu Terada; Yuichi Terashima; Francesco Tombesi; Hiroshi Tomida; Yohko Tsuboi; Masahiro Tsujimoto; Hiroshi Tsunemi; Takeshi Go Tsuru; Hiroyuki Uchida; Hideki Uchiyama; Yasunobu Uchiyama; Shutaro Ueda; Yoshihiro Ueda; Shin’ichiro Uno; C Megan Urry; Eugenio Ursino; Qian H S Wang; Shin Watanabe; Norbert Werner; Dan R Wilkins; Brian J Williams; Shinya Yamada; Hiroya Yamaguchi; Kazutaka Yamaoka; Noriko Y Yamasaki; Makoto Yamauchi; Shigeo Yamauchi; Tahir Yaqoob; Yoichi Yatsu; Daisuke Yonetoku; Irina Zhuravleva; Abderahmen Zoghbi, Extending the earlier measurements reported in Hitomi collaboration (2016, Nature, 535, 117), we examine the atmospheric gas motions within the central 100 kpc of the Perseus cluster using observations obtained with the Hitomi satellite. After correcting for the point spread function of the telescope and using optically thin emission lines, we find that the line-of-sight velocity dispersion of the hot gas is remarkably low and mostly uniform. The velocity dispersion reaches a maxima of approximately 200 km s(-1) toward the central active galactic nucleus (AGN) and toward the AGN inflated northwestern "ghost" bubble. Elsewhere within the observed region, the velocity dispersion appears constant around 100 km s(-1). We also detect a velocity gradient with a 100 km s(-1) amplitude across the cluster core, consistent with large-scale sloshing of the core gas. If the observed gas motions are isotropic, the kinetic pressure support is less than 10% of the thermal pressure support in the cluster core. The well-resolved, optically thin emission lines have Gaussian shapes, indicating that the turbulent driving scale is likely below 100 kpc, which is consistent with the size of the AGN jet inflated bubbles. We also report the first measurement of the ion temperature in the intracluster medium, which we find to be consistent with the electron temperature. In addition, we present a new measurement of the redshift of the brightest cluster galaxy NGC 1275., 01 Mar. 2018, 70, 2, Scientific journal, 10.1093/pasj/psx138

Refereed, Publications of the Astronomical Society of Japan, Oxford University Press (OUP), Measurements of resonant scattering in the Perseus Cluster core with Hitomi SXS*, Felix Aharonian; Hiroki Akamatsu; Fumie Akimoto; Steven W Allen; Lorella Angelini; Marc Audard; Hisamitsu Awaki; Magnus Axelsson; Aya Bamba; Marshall W Bautz; Roger Blandford; Laura W Brenneman; Gregory V Brown; Esra Bulbul; Edward M Cackett; Maria Chernyakova; Meng P Chiao; Paolo S Coppi; Elisa Costantini; Jelle de Plaa; Cor P de Vries; Jan-Willem den Herder; Chris Done; Tadayasu Dotani; Ken Ebisawa; Megan E Eckart; Teruaki Enoto; Yuichiro Ezoe; Andrew C Fabian; Carlo Ferrigno; Adam R Foster; Ryuichi Fujimoto; Yasushi Fukazawa; Maki Furukawa; Akihiro Furuzawa; Massimiliano Galeazzi; Luigi C Gallo; Poshak Gandhi; Margherita Giustini; Andrea Goldwurm; Liyi Gu; Matteo Guainazzi; Yoshito Haba; Kouichi Hagino; Kenji Hamaguchi; Ilana M Harrus; Isamu Hatsukade; Katsuhiro Hayashi; Takayuki Hayashi; Kiyoshi Hayashida; Junko S Hiraga; Ann Hornschemeier; Akio Hoshino; John P Hughes; Yuto Ichinohe; Ryo Iizuka; Hajime Inoue; Yoshiyuki Inoue; Manabu Ishida; Kumi Ishikawa; Yoshitaka Ishisaki; Masachika Iwai; Jelle Kaastra; Tim Kallman; Tsuneyoshi Kamae; Jun Kataoka; Satoru Katsuda; Nobuyuki Kawai; Richard L Kelley; Caroline A Kilbourne; Takao Kitaguchi; Shunji Kitamoto; Tetsu Kitayama; Takayoshi Kohmura; Motohide Kokubun; Katsuji Koyama; Shu Koyama; Peter Kretschmar; Hans A Krimm; Aya Kubota; Hideyo Kunieda; Philippe Laurent; Shiu-Hang Lee; Maurice A Leutenegger; Olivier O Limousin; Michael Loewenstein; Knox S Long; David Lumb; Greg Madejski; Yoshitomo Maeda; Daniel Maier; Kazuo Makishima; Maxim Markevitch; Hironori Matsumoto; Kyoko Matsushita; Dan McCammon; Brian R McNamara; Missagh Mehdipour; Eric D Miller; Jon M Miller; Shin Mineshige; Kazuhisa Mitsuda; Ikuyuki Mitsuishi; Takuya Miyazawa; Tsunefumi Mizuno; Hideyuki Mori; Koji Mori; Koji Mukai; Hiroshi Murakami; Richard F Mushotzky; Takao Nakagawa; Hiroshi Nakajima; Takeshi Nakamori; Shinya Nakashima; Kazuhiro Nakazawa; Kumiko K Nobukawa; Masayoshi Nobukawa; Hirofumi Noda; Hirokazu Odaka; Anna Ogorzalek; Takaya Ohashi; Masanori Ohno; Takashi Okajima; Naomi Ota; Masanobu Ozaki; Frits Paerels; Stéphane Paltani; Robert Petre; Ciro Pinto; Frederick S Porter; Katja Pottschmidt; Christopher S Reynolds; Samar Safi-Harb; Shinya Saito; Kazuhiro Sakai; Toru Sasaki; Goro Sato; Kosuke Sato; Rie Sato; Makoto Sawada; Norbert Schartel; Peter J Serlemtsos; Hiromi Seta; Megumi Shidatsu; Aurora Simionescu; Randall K Smith; Yang Soong; Łukasz Stawarz; Yasuharu Sugawara; Satoshi Sugita; Andrew Szymkowiak; Hiroyasu Tajima; Hiromitsu Takahashi; Tadayuki Takahashi; Shiníchiro Takeda; Yoh Takei; Toru Tamagawa; Takayuki Tamura; Takaaki Tanaka; Yasuo Tanaka; Yasuyuki T Tanaka; Makoto S Tashiro; Yuzuru Tawara; Yukikatsu Terada; Yuichi Terashima; Francesco Tombesi; Hiroshi Tomida; Yohko Tsuboi; Masahiro Tsujimoto; Hiroshi Tsunemi; Takeshi Go Tsuru; Hiroyuki Uchida; Hideki Uchiyama; Yasunobu Uchiyama; Shutaro Ueda; Yoshihiro Ueda; Shiníchiro Uno; C Megan Urry; Eugenio Ursino; Shin Watanabe; Norbert Werner; Dan R Wilkins; Brian J Williams; Shinya Yamada; Hiroya Yamaguchi; Kazutaka Yamaoka; Noriko Y Yamasaki; Makoto Yamauchi; Shigeo Yamauchi; Tahir Yaqoob; Yoichi Yatsu; Daisuke Yonetoku; Irina Zhuravleva; Abderahmen Zoghbi, Thanks to its high spectral resolution (similar to 5 eV at 6 keV), the Soft X-ray Spectrometer (SXS) on board Hitomi enables us to measure the detailed structure of spatially resolved emission lines from highly ionized ions in galaxy clusters for the first time. In this series of papers, using the SXS we have measured the velocities of gas motions, metallicities and the multi-temperature structure of the gas in the core of the Perseus Cluster. Here, we show that when inferring physical properties from line emissivities in systems like Perseus, the resonant scattering effect should be taken into account. In the Hitomi waveband, resonant scattering mostly affects the Fe XXV He alpha line (w)-the strongest line in the spectrum. The flux measured by Hitomi in this line is suppressed by a factor of similar to 1.3 in the inner similar to 30 kpc, compared to predictions for an optically thin plasma; the suppression decreases with the distance from the center. The w line also appears slightly broader than other lines from the same ion. The observed distortions of the w line flux, shape, and distance dependence are all consistent with the expected effect of the resonant scattering in the Perseus core. By measuring the ratio of fluxes in optically thick (w) and thin (Fe XXV forbidden, He beta, Ly alpha) lines, and comparing these ratios with predictions from Monte Carlo radiative transfer simulations, the velocities of gas motions have been obtained. The results are consistent with the direct measurements of gas velocities from line broadening described elsewhere in this series, although the systematic and statistical uncertainties remain significant. Further improvements in the predictions of line emissivities in plasma models, and deeper observations with future X-ray missions offering similar or better capabilities to the Hitomi SXS, will enable resonant scattering measurements to provide powerful constraints on the amplitude and anisotropy of cluster gas motions., 01 Mar. 2018, 70, 2, Scientific journal, 10.1093/pasj/psx127

Refereed, Publications of the Astronomical Society of Japan, Oxford University Press (OUP), Temperature structure in the Perseus cluster core observed with Hitomi*, Felix Aharonian; Hiroki Akamatsu; Fumie Akimoto; Steven W Allen; Lorella Angelini; Marc Audard; Hisamitsu Awaki; Magnus Axelsson; Aya Bamba; Marshall W Bautz; Roger Blandford; Laura W Brenneman; Gregory V Brown; Esra Bulbul; Edward M Cackett; Maria Chernyakova; Meng P Chiao; Paolo S Coppi; Elisa Costantini; Jelle de Plaa; Cor P de Vries; Jan-Willem den Herder; Chris Done; Tadayasu Dotani; Ken Ebisawa; Megan E Eckart; Teruaki Enoto; Yuichiro Ezoe; Andrew C Fabian; Carlo Ferrigno; Adam R Foster; Ryuichi Fujimoto; Yasushi Fukazawa; Maki Furukawa; Akihiro Furuzawa; Massimiliano Galeazzi; Luigi C Gallo; Poshak Gandhi; Margherita Giustini; Andrea Goldwurm; Liyi Gu; Matteo Guainazzi; Yoshito Haba; Kouichi Hagino; Kenji Hamaguchi; Ilana M Harrus; Isamu Hatsukade; Katsuhiro Hayashi; Takayuki Hayashi; Kiyoshi Hayashida; Junko S Hiraga; Ann Hornschemeier; Akio Hoshino; John P Hughes; Yuto Ichinohe; Ryo Iizuka; Hajime Inoue; Yoshiyuki Inoue; Manabu Ishida; Kumi Ishikawa; Yoshitaka Ishisaki; Masachika Iwai; Jelle Kaastra; Tim Kallman; Tsuneyoshi Kamae; Jun Kataoka; Yuichi Kato; Satoru Katsuda; Nobuyuki Kawai; Richard L Kelley; Caroline A Kilbourne; Takao Kitaguchi; Shunji Kitamoto; Tetsu Kitayama; Takayoshi Kohmura; Motohide Kokubun; Katsuji Koyama; Shu Koyama; Peter Kretschmar; Hans A Krimm; Aya Kubota; Hideyo Kunieda; Philippe Laurent; Shiu-Hang Lee; Maurice A Leutenegger; Olivier Limousin; Michael Loewenstein; Knox S Long; David Lumb; Greg Madejski; Yoshitomo Maeda; Daniel Maier; Kazuo Makishima; Maxim Markevitch; Hironori Matsumoto; Kyoko Matsushita; Dan McCammon; Brian R McNamara; Missagh Mehdipour; Eric D Miller; Jon M Miller; Shin Mineshige; Kazuhisa Mitsuda; Ikuyuki Mitsuishi; Takuya Miyazawa; Tsunefumi Mizuno; Hideyuki Mori; Koji Mori; Koji Mukai; Hiroshi Murakami; Richard F Mushotzky; Takao Nakagawa; Hiroshi Nakajima; Takeshi Nakamori; Shinya Nakashima; Kazuhiro Nakazawa; Kumiko K Nobukawa; Masayoshi Nobukawa; Hirofumi Noda; Hirokazu Odaka; Takaya Ohashi; Masanori Ohno; Takashi Okajima; Naomi Ota; Masanobu Ozaki; Frits Paerels; Stéphane Paltani; Robert Petre; Ciro Pinto; Frederick S Porter; Katja Pottschmidt; Christopher S Reynolds; Samar Safi-Harb; Shinya Saito; Kazuhiro Sakai; Toru Sasaki; Goro Sato; Kosuke Sato; Rie Sato; Makoto Sawada; Norbert Schartel; Peter J Serlemtsos; Hiromi Seta; Megumi Shidatsu; Aurora Simionescu; Randall K Smith; Yang Soong; Łukasz Stawarz; Yasuharu Sugawara; Satoshi Sugita; Andrew Szymkowiak; Hiroyasu Tajima; Hiromitsu Takahashi; Tadayuki Takahashi; Shiníchiro Takeda; Yoh Takei; Toru Tamagawa; Takayuki Tamura; Takaaki Tanaka; Yasuo Tanaka; Yasuyuki T Tanaka; Makoto S Tashiro; Yuzuru Tawara; Yukikatsu Terada; Yuichi Terashima; Francesco Tombesi; Hiroshi Tomida; Yohko Tsuboi; Masahiro Tsujimoto; Hiroshi Tsunemi; Takeshi Go Tsuru; Hiroyuki Uchida; Hideki Uchiyama; Yasunobu Uchiyama; Shutaro Ueda; Yoshihiro Ueda; Shiníchiro Uno; C Megan Urry; Eugenio Ursino; Shin Watanabe; Norbert Werner; Dan R Wilkins; Brian J Williams; Shinya Yamada; Hiroya Yamaguchi; Kazutaka Yamaoka; Noriko Y Yamasaki; Makoto Yamauchi; Shigeo Yamauchi; Tahir Yaqoob; Yoichi Yatsu; Daisuke Yonetoku; Irina Zhuravleva; Abderahmen Zoghbi, The present paper explains the temperature structure of X-ray emitting plasma in the core of the Perseus cluster based on 1.8-20.0 keV data obtained with the Soft X-ray Spectrometer (SXS) on board the Hitomi Observatory. A series of four observations was carried out, with a total effective exposure time of 338 ks that covered a central region of ∼7 in diameter. SXS was operated with an energy resolution of ∼5 eV (full width at half maximum) at 5.9 keV. Not only fine structures of K-shell lines in He-like ions, but also transitions from higher principal quantum numbers were clearly resolved from Si through Fe. That enabled us to perform temperature diagnostics using the line ratios of Si, S, Ar, Ca, and Fe, and to provide the first direct measurement of the excitation temperature and ionization temperature in the Perseus cluster. The observed spectrum is roughly reproduced by a single-temperature thermal plasma model in collisional ionization equilibrium, but detailed line-ratio diagnostics reveal slight deviations from this approximation. In particular, the data exhibit an apparent trend of increasing ionization temperature with the atomic mass, as well as small differences between the ionization and excitation temperatures for Fe, the only element for which both temperatures could be measured. The best-fit two-temperature models suggest a combination of 3 and 5 keV gas, which is consistent with the idea that the observed small deviations from a single-temperature approximation are due to the effects of projecting the known radial temperature gradient in the cluster core along the line of sight. A comparison with the Chandra/ACIS and the XMM-Newton/RGS results, on the other hand, suggests that additional lower-temperature components are present in the intracluster medium (ICM), but not detectable with Hitomi/SXS giving its 1.8-20 keV energy band., 01 Mar. 2018, 70, 2, Scientific journal, 10.1093/pasj/psy004

Refereed, Publications of the Astronomical Society of Japan, Oxford University Press (OUP), Atomic data and spectral modeling constraints from high-resolution X-ray observations of the Perseus cluster with Hitomi*, Hitomi Collaboration, Felix Aharonian; Hiroki Akamatsu; Fumie Akimoto; Steven W Allen; Lorella Angelini; Marc Audard; Hisamitsu Awaki; Magnus Axelsson; Aya Bamba; Marshall W Bautz; Roger Blandford; Laura W Brenneman; Gregory V Brown; Esra Bulbul; Edward M Cackett; Maria Chernyakova; Meng P Chiao; Paolo S Coppi; Elisa Costantini; Jelle de Plaa; Cor P de Vries; Jan-Willem den Herder; Chris Done; Tadayasu Dotani; Ken Ebisawa; Megan E Eckart; Teruaki Enoto; Yuichiro Ezoe; Andrew C Fabian; Carlo Ferrigno; Adam R Foster; Ryuichi Fujimoto; Yasushi Fukazawa; Akihiro Furuzawa; Massimiliano Galeazzi; Luigi C Gallo; Poshak Gandhi; Margherita Giustini; Andrea Goldwurm; Liyi Gu; Matteo Guainazzi; Yoshito Haba; Kouichi Hagino; Kenji Hamaguchi; Ilana M Harrus; Isamu Hatsukade; Katsuhiro Hayashi; Takayuki Hayashi; Kiyoshi Hayashida; Natalie Hell; Junko S Hiraga; Ann Hornschemeier; Akio Hoshino; John P Hughes; Yuto Ichinohe; Ryo Iizuka; Hajime Inoue; Yoshiyuki Inoue; Manabu Ishida; Kumi Ishikawa; Yoshitaka Ishisaki; Masachika Iwai; Jelle Kaastra; Tim Kallman; Tsuneyoshi Kamae; Jun Kataoka; Satoru Katsuda; Nobuyuki Kawai; Richard L Kelley; Caroline A Kilbourne; Takao Kitaguchi; Shunji Kitamoto; Tetsu Kitayama; Takayoshi Kohmura; Motohide Kokubun; Katsuji Koyama; Shu Koyama; Peter Kretschmar; Hans A Krimm; Aya Kubota; Hideyo Kunieda; Philippe Laurent; Shiu-Hang Lee; Maurice A Leutenegger; Olivier Limousin; Michael Loewenstein; Knox S Long; David Lumb; Greg Madejski; Yoshitomo Maeda; Daniel Maier; Kazuo Makishima; Maxim Markevitch; Hironori Matsumoto; Kyoko Matsushita; Dan McCammon; Brian R McNamara; Missagh Mehdipour; Eric D Miller; Jon M Miller; Shin Mineshige; Kazuhisa Mitsuda; Ikuyuki Mitsuishi; Takuya Miyazawa; Tsunefumi Mizuno; Hideyuki Mori; Koji Mori; Koji Mukai; Hiroshi Murakami; Richard F Mushotzky; Takao Nakagawa; Hiroshi Nakajima; Takeshi Nakamori; Shinya Nakashima; Kazuhiro Nakazawa; Kumiko K Nobukawa; Masayoshi Nobukawa; Hirofumi Noda; Hirokazu Odaka; Takaya Ohashi; Masanori Ohno; Takashi Okajima; Naomi Ota; Masanobu Ozaki; Frits Paerels; Stéphane Paltani; Robert Petre; Ciro Pinto; Frederick S Porter; Katja Pottschmidt; Christopher S Reynolds; Samar Safi-Harb; Shinya Saito; Kazuhiro Sakai; Toru Sasaki; Goro Sato; Kosuke Sato; Rie Sato; Makoto Sawada; Norbert Schartel; Peter J Serlemtsos; Hiromi Seta; Megumi Shidatsu; Aurora Simionescu; Randall K Smith; Yang Soong; Łukasz Stawarz; Yasuharu Sugawara; Satoshi Sugita; Andrew Szymkowiak; Hiroyasu Tajima; Hiromitsu Takahashi; Tadayuki Takahashi; Shin’ichiro Takeda; Yoh Takei; Toru Tamagawa; Takayuki Tamura; Takaaki Tanaka; Yasuo Tanaka; Yasuyuki T Tanaka; Makoto S Tashiro; Yuzuru Tawara; Yukikatsu Terada; Yuichi Terashima; Francesco Tombesi; Hiroshi Tomida; Yohko Tsuboi; Masahiro Tsujimoto; Hiroshi Tsunemi; Takeshi Go Tsuru; Hiroyuki Uchida; Hideki Uchiyama; Yasunobu Uchiyama; Shutaro Ueda; Yoshihiro Ueda; Shin’ichiro Uno; C Megan Urry; Eugenio Ursino; Shin Watanabe; Norbert Werner; Dan R Wilkins; Brian J Williams; Shinya Yamada; Hiroya Yamaguchi; Kazutaka Yamaoka; Noriko Y Yamasaki; Makoto Yamauchi; Shigeo Yamauchi; Tahir Yaqoob; Yoichi Yatsu; Daisuke Yonetoku; Irina Zhuravleva; Abderahmen Zoghbi; A J J Raassen, 01 Mar. 2018, 70, 2, Scientific journal, 10.1093/pasj/psx156

Refereed, Publications of the Astronomical Society of Japan, Oxford University Press (OUP), Hitomi observation of radio galaxy NGC 1275: The first X-ray microcalorimeter spectroscopy of Fe-Kα line emission from an active galactic nucleus*, Hitomi Collaboration, Felix Aharonian; Hiroki Akamatsu; Fumie Akimoto; Steven W Allen; Lorella Angelini; Marc Audard; Hisamitsu Awaki; Magnus Axelsson; Aya Bamba; Marshall W Bautz; Roger Blandford; Laura W Brenneman; Gregory V Brown; Esra Bulbul; Edward M Cackett; Maria Chernyakova; Meng P Chiao; Paolo S Coppi; Elisa Costantini; Jelle de Plaa; Cor P de Vries; Jan-Willem den Herder; Chris Done; Tadayasu Dotani; Ken Ebisawa; Megan E Eckart; Teruaki Enoto; Yuichiro Ezoe; Andrew C Fabian; Carlo Ferrigno; Adam R Foster; Ryuichi Fujimoto; Yasushi Fukazawa; Akihiro Furuzawa; Massimiliano Galeazzi; Luigi C Gallo; Poshak Gandhi; Margherita Giustini; Andrea Goldwurm; Liyi Gu; Matteo Guainazzi; Yoshito Haba; Kouichi Hagino; Kenji Hamaguchi; Ilana M Harrus; Isamu Hatsukade; Katsuhiro Hayashi; Takayuki Hayashi; Kiyoshi Hayashida; Junko S Hiraga; Ann Hornschemeier; Akio Hoshino; John P Hughes; Yuto Ichinohe; Ryo Iizuka; Hajime Inoue; Yoshiyuki Inoue; Manabu Ishida; Kumi Ishikawa; Yoshitaka Ishisaki; Masachika Iwai; Jelle Kaastra; Tim Kallman; Tsuneyoshi Kamae; Jun Kataoka; Satoru Katsuda; Nobuyuki Kawai; Richard L Kelley; Caroline A Kilbourne; Takao Kitaguchi; Shunji Kitamoto; Tetsu Kitayama; Takayoshi Kohmura; Motohide Kokubun; Katsuji Koyama; Shu Koyama; Peter Kretschmar; Hans A Krimm; Aya Kubota; Hideyo Kunieda; Philippe Laurent; Shiu-Hang Lee; Maurice A Leutenegger; Olivier O Limousin; Michael Loewenstein; Knox S Long; David Lumb; Greg Madejski; Yoshitomo Maeda; Daniel Maier; Kazuo Makishima; Maxim Markevitch; Hironori Matsumoto; Kyoko Matsushita; Dan McCammon; Brian R McNamara; Missagh Mehdipour; Eric D Miller; Jon M Miller; Shin Mineshige; Kazuhisa Mitsuda; Ikuyuki Mitsuishi; Takuya Miyazawa; Tsunefumi Mizuno; Hideyuki Mori; Koji Mori; Koji Mukai; Hiroshi Murakami; Richard F Mushotzky; Takao Nakagawa; Hiroshi Nakajima; Takeshi Nakamori; Shinya Nakashima; Kazuhiro Nakazawa; Kumiko K Nobukawa; Masayoshi Nobukawa; Hirofumi Noda; Hirokazu Odaka; Takaya Ohashi; Masanori Ohno; Takashi Okajima; Naomi Ota; Masanobu Ozaki; Frits Paerels; Stéphane Paltani; Robert Petre; Ciro Pinto; Frederick S Porter; Katja Pottschmidt; Christopher S Reynolds; Samar Safi-Harb; Shinya Saito; Kazuhiro Sakai; Toru Sasaki; Goro Sato; Kosuke Sato; Rie Sato; Makoto Sawada; Norbert Schartel; Peter J Serlemitsos; Hiromi Seta; Megumi Shidatsu; Aurora Simionescu; Randall K Smith; Yang Soong; Łukasz Stawarz; Yasuharu Sugawara; Satoshi Sugita; Andrew Szymkowiak; Hiroyasu Tajima; Hiromitsu Takahashi; Tadayuki Takahashi; Shin’ichiro Takeda; Yoh Takei; Toru Tamagawa; Takayuki Tamura; Takaaki Tanaka; Yasuo Tanaka; Yasuyuki T Tanaka; Makoto S Tashiro; Yuzuru Tawara; Yukikatsu Terada; Yuichi Terashima; Francesco Tombesi; Hiroshi Tomida; Yohko Tsuboi; Masahiro Tsujimoto; Hiroshi Tsunemi; Takeshi Go Tsuru; Hiroyuki Uchida; Hideki Uchiyama; Yasunobu Uchiyama; Shutaro Ueda; Yoshihiro Ueda; Shin’ichiro Uno; C Megan Urry; Eugenio Ursino; Shin Watanabe; Norbert Werner; Dan R Wilkins; Brian J Williams; Shinya Yamada; Hiroya Yamaguchi; Kazutaka Yamaoka; Noriko Y Yamasaki; Makoto Yamauchi; Shigeo Yamauchi; Tahir Yaqoob; Yoichi Yatsu; Daisuke Yonetoku; Irina Zhuravleva; Abderahmen Zoghbi; Taiki Kawamuro, 01 Mar. 2018, 70, 2, Scientific journal, 10.1093/pasj/psx147

Refereed, Publications of the Astronomical Society of Japan, Oxford University Press (OUP), Search for thermal X-ray features from the Crab nebula with the Hitomi soft X-ray spectrometer*, Hitomi Collaboration, Felix Aharonian; Hiroki Akamatsu; Fumie Akimoto; Steven W Allen; Lorella Angelini; Marc Audard; Hisamitsu Awaki; Magnus Axelsson; Aya Bamba; Marshall W Bautz; Roger Blandford; Laura W Brenneman; Gregory V Brown; Esra Bulbul; Edward M Cackett; Maria Chernyakova; Meng P Chiao; Paolo S Coppi; Elisa Costantini; Jelle de Plaa; Cor P de Vries; Jan-Willem den Herder; Chris Done; Tadayasu Dotani; Ken Ebisawa; Megan E Eckart; Teruaki Enoto; Yuichiro Ezoe; Andrew C Fabian; Carlo Ferrigno; Adam R Foster; Ryuichi Fujimoto; Yasushi Fukazawa; Akihiro Furuzawa; Massimiliano Galeazzi; Luigi C Gallo; Poshak Gandhi; Margherita Giustini; Andrea Goldwurm; Liyi Gu; Matteo Guainazzi; Yoshito Haba; Kouichi Hagino; Kenji Hamaguchi; Ilana M Harrus; Isamu Hatsukade; Katsuhiro Hayashi; Takayuki Hayashi; Kiyoshi Hayashida; Junko S Hiraga; Ann Hornschemeier; Akio Hoshino; John P Hughes; Yuto Ichinohe; Ryo Iizuka; Hajime Inoue; Yoshiyuki Inoue; Manabu Ishida; Kumi Ishikawa; Yoshitaka Ishisaki; Jelle Kaastra; Tim Kallman; Tsuneyoshi Kamae; Jun Kataoka; Satoru Katsuda; Nobuyuki Kawai; Richard L Kelley; Caroline A Kilbourne; Takao Kitaguchi; Shunji Kitamoto; Tetsu Kitayama; Takayoshi Kohmura; Motohide Kokubun; Katsuji Koyama; Shu Koyama; Peter Kretschmar; Hans A Krimm; Aya Kubota; Hideyo Kunieda; Philippe Laurent; Shiu-Hang Lee; Maurice A Leutenegger; Olivier Limousin; Michael Loewenstein; Knox S Long; David Lumb; Greg Madejski; Yoshitomo Maeda; Daniel Maier; Kazuo Makishima; Maxim Markevitch; Hironori Matsumoto; Kyoko Matsushita; Dan McCammon; Brian R McNamara; Missagh Mehdipour; Eric D Miller; Jon M Miller; Shin Mineshige; Kazuhisa Mitsuda; Ikuyuki Mitsuishi; Takuya Miyazawa; Tsunefumi Mizuno; Hideyuki Mori; Koji Mori; Koji Mukai; Hiroshi Murakami; Richard F Mushotzky; Takao Nakagawa; Hiroshi Nakajima; Takeshi Nakamori; Shinya Nakashima; Kazuhiro Nakazawa; Kumiko K Nobukawa; Masayoshi Nobukawa; Hirofumi Noda; Hirokazu Odaka; Takaya Ohashi; Masanori Ohno; Takashi Okajima; Naomi Ota; Masanobu Ozaki; Frits Paerels; Stéphane Paltani; Robert Petre; Ciro Pinto; Frederick S Porter; Katja Pottschmidt; Christopher S Reynolds; Samar Safi-Harb; Shinya Saito; Kazuhiro Sakai; Toru Sasaki; Goro Sato; Kosuke Sato; Rie Sato; Toshiki Sato; Makoto Sawada; Norbert Schartel; Peter J Serlemtsos; Hiromi Seta; Megumi Shidatsu; Aurora Simionescu; Randall K Smith; Yang Soong; Łukasz Stawarz; Yasuharu Sugawara; Satoshi Sugita; Andrew Szymkowiak; Hiroyasu Tajima; Hiromitsu Takahashi; Tadayuki Takahashi; Shin΄ichiro Takeda; Yoh Takei; Toru Tamagawa; Takayuki Tamura; Takaaki Tanaka; Yasuo Tanaka; Yasuyuki T Tanaka; Makoto S Tashiro; Yuzuru Tawara; Yukikatsu Terada; Yuichi Terashima; Francesco Tombesi; Hiroshi Tomida; Yohko Tsuboi; Masahiro Tsujimoto; Hiroshi Tsunemi; Takeshi Go Tsuru; Hiroyuki Uchida; Hideki Uchiyama; Yasunobu Uchiyama; Shutaro Ueda; Yoshihiro Ueda; Shin΄ichiro Uno; C Megan Urry; Eugenio Ursino; Shin Watanabe; Norbert Werner; Dan R Wilkins; Brian J Williams; Shinya Yamada; Hiroya Yamaguchi; Kazutaka Yamaoka; Noriko Y Yamasaki; Makoto Yamauchi; Shigeo Yamauchi; Tahir Yaqoob; Yoichi Yatsu; Daisuke Yonetoku; Irina Zhuravleva; Abderahmen Zoghbi; Nozomu Tominaga; Takashi J Moriya, The Crab nebula originated from a core-collapse supernova (SN) explosion observed in 1054 AD. When viewed as a supernova remnant (SNR), it has an anomalously low observed ejecta mass and kinetic energy for an Fe-core-collapse SN. Intensive searches have been made for a massive shell that solves this discrepancy, but none has been detected. An alternative idea is that SN 1054 is an electron-capture (EC) explosion with a lower explosion energy by an order of magnitude than Fe-core-collapse SNe. X-ray imaging searches were performed for the plasma emission from the shell in the Crab outskirts to set a stringent upper limit on the X-ray emitting mass. However, the extreme brightness of the source hampers access to its vicinity. We thus employed spectroscopic technique using the X-ray micro-calorimeter on board the Hitomi satellite. By exploiting its superb energy resolution, we set an upper limit for emission or absorption features from as yet undetected thermal plasma in the 2-12 keV range. We also re-evaluated the existing Chandra and XMM-Newton data. By assembling these results, a new upper limit was obtained for the X-ray plasma mass of less than or similar to 1 M-circle dot for a wide range of assumed shell radius, size, and plasma temperature values both in and out of collisional equilibrium. To compare with the observation, we further performed hydrodynamic simulations of the Crab SNR for two SN models (Fe-core versus EC) under two SN environments (uniform interstellar medium versus progenitor wind). We found that the observed mass limit can be compatible with both SN models if the SN environment has a low density of less than or similar to 0.03 cm(-3) (Fe core) or less than or similar to 0.1 cm(-3) (EC) for the uniform density, or a progenitor wind density somewhat less than that provided by amass loss rate of 10(-5) M-circle dot yr(-1) at 20 km s(-1) for the wind environment., 01 Mar. 2018, 70, 2, Scientific journal, 10.1093/pasj/psx072

Refereed, Publications of the Astronomical Society of Japan, Hitomi X-ray studies of giant radio pulses from the Crab pulsar, Felix Aharonian; Hiroki Akamatsu; Fumie Akimoto; Steven W. Allen; Lorella Angelini; Marc Audard; Hisamitsu Awaki; Magnus Axelsson; Aya Bamba; Marshall W. Bautz; Roger Blandford; Laura W. Brenneman; Gregory V. Brown; Esra Bulbul; Edward M. Cackett; Maria Chernyakova; Meng P. Chiao; Paolo S. Coppi; Elisa Costantini; Jelle De Plaa; Cor P. De Vries; Jan Willem Den Herder; Chris Done; Tadayasu Dotani; Ken Ebisawa; Megan E. Eckart; Teruaki Enoto; Yuichiro Ezoe; Andrew C. Fabian; Carlo Ferrigno; Adam R. Foster; Ryuichi Fujimoto; Yasushi Fukazawa; Akihiro Furuzawa; Massimiliano Galeazzi; Luigi C. Gallo; Poshak Gandhi; Margherita Giustini; Andrea Goldwurm; Liyi Gu; Matteo Guainazzi; Yoshito Haba; Kouichi Hagino; Kenji Hamaguchi; Ilana M. Harrus; Isamu Hatsukade; Katsuhiro Hayashi; Takayuki Hayashi; Kiyoshi Hayashida; Junko S. Hiraga; Ann Hornschemeier; Akio Hoshino; John P. Hughes; Yuto Ichinohe; Ryo Iizuka; Hajime Inoue; Yoshiyuki Inoue; Manabu Ishida; Kumi Ishikawa; Yoshitaka Ishisaki; Masachika Iwai; Jelle Kaastra; Tim Kallman; Tsuneyoshi Kamae; Jun Kataoka; Satoru Katsuda; Nobuyuki Kawai; Richard L. Kelley; Caroline A. Kilbourne; Takao Kitaguchi; Shunji Kitamoto; Tetsu Kitayama; Takayoshi Kohmura; Motohide Kokubun; Katsuji Koyama; Shu Koyama; Peter Kretschmar; Hans A. Krimm; Aya Kubota; Hideyo Kunieda; Philippe Laurent; L. E.E. Shiu-Hang; Maurice A. Leutenegger; Olivier O. Limousin; Michael Loewenstein; Knox S. Long; David Lumb; Greg Madejski; Yoshitomo Maeda; Daniel Maier; Kazuo Makishima; Maxim Markevitch; Hironori Matsumoto; Kyoko Matsushita; Dan McCammon; Brian R. McNamara; Missagh Mehdipour; Eric D. Miller; Jon M. Miller; Shin Mineshige, © The Author(s) 2017. Published by Oxford University Press on behalf of the Astronomical Society of Japan. To search for giant X-ray pulses correlated with the giant radio pulses (GRPs) from the Crab pulsar, we performed a simultaneous observation of the Crab pulsar with the X-ray satellite Hitomi in the 2-300 keV band and the Kashima NICT radio telescope in the 1.4-1.7 GHz band with a net exposure of about 2 ks on 2016 March 25, just before the loss of the Hitomi mission. The timing performance of the Hitomi instruments was confirmed to meet the timing requirement and about 1000 and 100 GRPs were simultaneously observed at the main pulse and inter-pulse phases, respectively, and we found no apparent correlation between the giant radio pulses and the X-ray emission in either the main pulse or inter-pulse phase. All variations are within the 2 σ fluctuations of the X-ray fluxes at the pulse peaks, and the 3 σ upper limits of variations of main pulse or inter-pulse GRPs are 22% or 80% of the peak flux in a 0.20 phase width, respectively, in the 2-300 keV band. The values for main pulse or inter-pulse GRPs become 25% or 110%, respectively, when the phase width is restricted to the 0.03 phase. Among the upper limits from the Hitomi satellite, those in the 4.5-10 keV and 70-300 keV bands are obtained for the first time, and those in other bands are consistent with previous reports. Numerically, the upper limits of the main pulse and inter-pulse GRPs in the 0.20 phase width are about (2.4 and 9.3) × 10−11 erg cm−2, respectively. No significant variability in pulse profiles implies that the GRPs originated from a local place within the magnetosphere. Although the number of photon-emitting particles should temporarily increase to account for the brightening of the radio emission, the results do not statistically rule out variations correlated with the GRPs, because the possible X-ray enhancement may appear due to a >0.02% brightening of the pulse-peak flux under such conditions., 01 Mar. 2018, 70, 2, 15 (18 pages), Scientific journal, 10.1093/pasj/psx083

Refereed, Publications of the Astronomical Society of Japan, Oxford University Press (OUP), Hitomi observations of the LMC SNR N 132 D: Highly redshifted X-ray emission from iron ejecta*, Hitomi Collaboration, Felix Aharonian; Hiroki Akamatsu; Fumie Akimoto; Steven W Allen; Lorella Angelini; Marc Audard; Hisamitsu Awaki; Magnus Axelsson; Aya Bamba; Marshall W Bautz; Roger Blandford; Laura W Brenneman; Gregory V Brown; Esra Bulbul; Edward M Cackett; Maria Chernyakova; Meng P Chiao; Paolo S Coppi; Elisa Costantini; Jelle de Plaa; Cor P de Vries; Jan-Willem den Herder; Chris Done; Tadayasu Dotani; Ken Ebisawa; Megan E Eckart; Teruaki Enoto; Yuichiro Ezoe; Andrew C Fabian; Carlo Ferrigno; Adam R Foster; Ryuichi Fujimoto; Yasushi Fukazawa; Akihiro Furuzawa; Massimiliano Galeazzi; Luigi C Gallo; Poshak Gandhi; Margherita Giustini; Andrea Goldwurm; Liyi Gu; Matteo Guainazzi; Yoshito Haba; Kouichi Hagino; Kenji Hamaguchi; Ilana M Harrus; Isamu Hatsukade; Katsuhiro Hayashi; Takayuki Hayashi; Kiyoshi Hayashida; Junko S Hiraga; Ann Hornschemeier; Akio Hoshino; John P Hughes; Yuto Ichinohe; Ryo Iizuka; Hajime Inoue; Yoshiyuki Inoue; Manabu Ishida; Kumi Ishikawa; Yoshitaka Ishisaki; Masachika Iwai; Jelle Kaastra; Tim Kallman; Tsuneyoshi Kamae; Jun Kataoka; Satoru Katsuda; Nobuyuki Kawai; Richard L Kelley; Caroline A Kilbourne; Takao Kitaguchi; Shunji Kitamoto; Tetsu Kitayama; Takayoshi Kohmura; Motohide Kokubun; Katsuji Koyama; Shu Koyama; Peter Kretschmar; Hans A Krimm; Aya Kubota; Hideyo Kunieda; Philippe Laurent; Shiu-Hang Lee; Maurice A Leutenegger; Olivier Limousin; Michael Loewenstein; Knox S Long; David Lumb; Greg Madejski; Yoshitomo Maeda; Daniel Maier; Kazuo Makishima; Maxim Markevitch; Hironori Matsumoto; Kyoko Matsushita; Dan McCammon; Brian R McNamara; Missagh Mehdipour; Eric D Miller; Jon M Miller; Shin Mineshige; Kazuhisa Mitsuda; Ikuyuki Mitsuishi; Takuya Miyazawa; Tsunefumi Mizuno; Hideyuki Mori; Koji Mori; Koji Mukai; Hiroshi Murakami; Richard F Mushotzky; Takao Nakagawa; Hiroshi Nakajima; Takeshi Nakamori; Shinya Nakashima; Kazuhiro Nakazawa; Kumiko K Nobukawa; Masayoshi Nobukawa; Hirofumi Noda; Hirokazu Odaka; Takaya Ohashi; Masanori Ohno; Takashi Okajima; Naomi Ota; Masanobu Ozaki; Frits Paerels; Stéphane Paltani; Robert Petre; Ciro Pinto; Frederick S Porter; Katja Pottschmidt; Christopher S Reynolds; Samar Safi-Harb; Shinya Saito; Kazuhiro Sakai; Toru Sasaki; Goro Sato; Kosuke Sato; Rie Sato; Toshiki Sato; Makoto Sawada; Norbert Schartel; Peter J Serlemtsos; Hiromi Seta; Megumi Shidatsu; Aurora Simionescu; Randall K Smith; Yang Soong; Łukasz Stawarz; Yasuharu Sugawara; Satoshi Sugita; Andrew Szymkowiak; Hiroyasu Tajima; Hiromitsu Takahashi; Tadayuki Takahashi; Shin’ichiro Takeda; Yoh Takei; Toru Tamagawa; Takayuki Tamura; Takaaki Tanaka; Yasuo Tanaka; Yasuyuki T Tanaka; Makoto S Tashiro; Yuzuru Tawara; Yukikatsu Terada; Yuichi Terashima; Francesco Tombesi; Hiroshi Tomida; Yohko Tsuboi; Masahiro Tsujimoto; Hiroshi Tsunemi; Takeshi Go Tsuru; Hiroyuki Uchida; Hideki Uchiyama; Yasunobu Uchiyama; Shutaro Ueda; Yoshihiro Ueda; Shin’ichiro Uno; C Megan Urry; Eugenio Ursino; Shin Watanabe; Norbert Werner; Dan R Wilkins; Brian J Williams; Shinya Yamada; Hiroya Yamaguchi; Kazutaka Yamaoka; Noriko Y Yamasaki; Makoto Yamauchi; Shigeo Yamauchi; Tahir Yaqoob; Yoichi Yatsu; Daisuke Yonetoku; Irina Zhuravleva; Abderahmen Zoghbi, 01 Mar. 2018, 70, 2, Scientific journal, 10.1093/pasj/psx151

Refereed, Publications of the Astronomical Society of Japan, Oxford University Press (OUP), Glimpse of the highly obscured HMXB IGR J16318−4848 with Hitomi*, Hitomi Collaboration; Felix Aharonian; Hiroki Akamatsu; Fumie Akimoto; Steven W Allen; Lorella Angelini; Marc Audard; Hisamitsu Awaki; Magnus Axelsson; Aya Bamba; Marshall W Bautz; Roger Blandford; Laura W Brenneman; Gregory V Brown; Esra Bulbul; Edward M Cackett; Maria Chernyakova; Meng P Chiao; Paolo S Coppi; Elisa Costantini; Jelle de Plaa; Cor P de Vries; Jan-Willem den Herder; Chris Done; Tadayasu Dotani; Ken Ebisawa; Megan E Eckart; Teruaki Enoto; Yuichiro Ezoe; Andrew C Fabian; Carlo Ferrigno; Adam R Foster; Ryuichi Fujimoto; Yasushi Fukazawa; Akihiro Furuzawa; Massimiliano Galeazzi; Luigi C Gallo; Poshak Gandhi; Margherita Giustini; Andrea Goldwurm; Liyi Gu; Matteo Guainazzi; Yoshito Haba; Kouichi Hagino; Kenji Hamaguchi; Ilana M Harrus; Isamu Hatsukade; Katsuhiro Hayashi; Takayuki Hayashi; Kiyoshi Hayashida; Junko S Hiraga; Ann Hornschemeier; Akio Hoshino; John P Hughes; Yuto Ichinohe; Ryo Iizuka; Hajime Inoue; Yoshiyuki Inoue; Manabu Ishida; Kumi Ishikawa; Yoshitaka Ishisaki; Masachika Iwai; Jelle Kaastra; Tim Kallman; Tsuneyoshi Kamae; Jun Kataoka; Satoru Katsuda; Nobuyuki Kawai; Richard L Kelley; Caroline A Kilbourne; Takao Kitaguchi; Shunji Kitamoto; Tetsu Kitayama; Takayoshi Kohmura; Motohide Kokubun; Katsuji Koyama; Shu Koyama; Peter Kretschmar; Hans A Krimm; Aya Kubota; Hideyo Kunieda; Philippe Laurent; Shiu-Hang Lee; Maurice A Leutenegger; Olivier O Limousin; Michael Loewenstein; Knox S Long; David Lumb; Greg Madejski; Yoshitomo Maeda; Daniel Maier; Kazuo Makishima; Maxim Markevitch; Hironori Matsumoto; Kyoko Matsushita; Dan McCammon; Brian R McNamara; Missagh Mehdipour; Eric D Miller; Jon M Miller; Shin Mineshige; Kazuhisa Mitsuda; Ikuyuki Mitsuishi; Takuya Miyazawa; Tsunefumi Mizuno; Hideyuki Mori; Koji Mori; Koji Mukai; Hiroshi Murakami; Richard F Mushotzky; Takao Nakagawa; Hiroshi Nakajima; Takeshi Nakamori; Shinya Nakashima; Kazuhiro Nakazawa; Kumiko K Nobukawa; Masayoshi Nobukawa; Hirofumi Noda; Hirokazu Odaka; Takaya Ohashi; Masanori Ohno; Takashi Okajima; Naomi Ota; Masanobu Ozaki; Frits Paerels; Stéphane Paltani; Robert Petre; Ciro Pinto; Frederick S Porter; Katja Pottschmidt; Christopher S Reynolds; Samar Safi-Harb; Shinya Saito; Kazuhiro Sakai; Toru Sasaki; Goro Sato; Kosuke Sato; Rie Sato; Makoto Sawada; Norbert Schartel; Peter J Serlemtsos; Hiromi Seta; Megumi Shidatsu; Aurora Simionescu; Randall K Smith; Yang Soong; Łukasz Stawarz; Yasuharu Sugawara; Satoshi Sugita; Andrew Szymkowiak; Hiroyasu Tajima; Hiromitsu Takahashi; Tadayuki Takahashi; Shiníchiro Takeda; Yoh Takei; Toru Tamagawa; Takayuki Tamura; Takaaki Tanaka; Yasuo Tanaka; Yasuyuki T Tanaka; Makoto S Tashiro; Yuzuru Tawara; Yukikatsu Terada; Yuichi Terashima; Francesco Tombesi; Hiroshi Tomida; Yohko Tsuboi; Masahiro Tsujimoto; Hiroshi Tsunemi; Takeshi Go Tsuru; Hiroyuki Uchida; Hideki Uchiyama; Yasunobu Uchiyama; Shutaro Ueda; Yoshihiro Ueda; Shiníchiro Uno; C Megan Urry; Eugenio Ursino; Shin Watanabe; Norbert Werner; Dan R Wilkins; Brian J Williams; Shinya Yamada; Hiroya Yamaguchi; Kazutaka Yamaoka; Noriko Y Yamasaki; Makoto Yamauchi; Shigeo Yamauchi; Tahir Yaqoob; Yoichi Yatsu; Daisuke Yonetoku; Irina Zhuravleva; Abderahmen Zoghbi; Nozomi Nakaniwa, 01 Mar. 2018, 70, 2, Scientific journal, 10.1093/pasj/psx154

Refereed, Publications of the Astronomical Society of Japan, Oxford University Press (OUP), Discovery of 6.4 keV line and soft X-ray emissions from G323.7−1.0 with Suzaku, Shigetaka Saji; Hironori Matsumoto; Masayoshi Nobukawa; Kumiko K Nobukawa; Hideki Uchiyama; Shigeo Yamauchi; Katsuji Koyama, In this paper, the Suzaku X-ray data of the Galactic supernova remnant (SNR) candidate G323.7−1.0 are analyzed to search for X-ray emissions. Spatially extended enhancements in the 6.4 keV line and in soft X-rays are found inside or on the radio shell. The soft X-ray enhancement would be the hottest part of the shell-like X-ray emission along the radio shell. The 6.4 keV line enhancement is detected at a significance level of 4.1 σ. The lower limit of the equivalent width (EW) is 1.2 keV. The energy centroid of the 6.4 keV line is 6.40 ± 0.04 keV, indicating that the iron is less ionized than the Ne-like state. If the 6.4 keV line originates from ionizing non-equilibrium thermal plasma, presence of iron-rich ejecta in a low-ionization state is required, which is disfavored by the relatively old age of the SNR. The 6.4 keV line enhancement would be due to K-shell ionization of iron atoms in a dense interstellar medium by high-energy particles. Since there is no irradiating X-ray source, the origin of the 6.4 keV line enhancement is not likely the photoionization. The large EW can only be explained by K-shell ionization due to cosmic-ray protons with an energy of ∼10 MeV, which might be generated by the shock acceleration in G323.7−1.0., 01 Mar. 2018, 70, 2, Scientific journal, 10.1093/pasj/psx158

Refereed, Astrophysical Journal, Institute of Physics Publishing, Evidence for a Neutral Iron Line Generated by MeV Protons from Supernova Remnants Interacting with Molecular Clouds, Kumiko K. Nobukawa; Masayoshi Nobukawa; Katsuji Koyama; Shigeo Yamauchi; Hideki Uchiyama; Hiromichi Okon; Takaaki Tanaka; Hiroyuki Uchida; Takeshi G. Tsuru, Supernova remnants (SNRs) have been prime candidates for Galactic cosmic-ray accelerators. When low-energy cosmic-ray protons (LECRp) collide with interstellar gas, they ionize neutral iron atoms and emit the neutral iron line (Fe i Kα) at 6.40 keV. We search for the iron K-shell line in seven SNRs from the Suzaku archive data of the Galactic plane in the 6° ≲ l ≲ 40°, < 1° region. All of these SNRs interact with molecular clouds. We discover Fe i Kα line emissions from five SNRs (W28, Kes 67, Kes 69, Kes 78, and W44). The spectra and morphologies suggest that the Fe i Kα line is produced by interactions between LECRp and the adjacent cold gas. The proton energy density is estimated to be 10-100 eV cm-3, which is more than 10 times higher than that in the ambient interstellar medium., 20 Feb. 2018, 854, 2, 87 (10 pages), Scientific journal, 10.3847/1538-4357/aaa8dc

Refereed, Journal of Astronomical Telescopes, Instruments, and Systems, SPIE, Inorbit performance of the Hard X-ray Telescope (HXT) on board the Hitomi (ASTRO-H) satellite, Hironori Matsumoto; Hisamitsu Awaki; Manabu Ishida; Akihiro Furuzawa; Shigeo Yamauchi; Yoshitomo Maeda; Ikuyuki Mitsuishi; Yoshito Haba; Takayuki Hayashi; Ryo Iizuka; Kazunori Ishibashi; Masayuki Itoh; Hideyo Kunieda; Takuya Miyazawa; Hideyuki Mori; Takashi Okajima; Satoshi Sugita; Keisuke Tamura; Yuzuru Tawara, Hitomi (ASTRO-H) carries two Hard X-ray Telescopes (HXTs), which can focus x-rays up to 80 keV. Combined with the hard x-ray imagers (HXIs) that detect the focused x-rays, imaging spectroscopy in the high-energy band from 5 to 80 keV is made possible. We studied characteristics of HXTs after the launch, such as the encircled energy function (EEF) and the effective area using the data of a Crab observation. The half power diameters (HPDs) in the 5- to 80-keV band evaluated from the EEFs are 1.59 arcmin for HXT-1 and 1.65 arcmin for HXT-2. Those are consistent with the HPDs measured with ground experiments when uncertainties are taken into account. We can conclude that there is no significant change in the characteristics of the HXTs before and after the launch. The off-axis angle of the aim point from the optical axis is evaluated to be < 0.5 arcmin for both HXT-1 and HXT-2. The best-fit parameters for the Crab spectrum obtained with the HXT-HXI system are consistent with the canonical values., 01 Jan. 2018, 4, 1, 011209, Scientific journal, 10.1117/1.JATIS.4.1.011212

Refereed, Journal of Astronomical Telescopes, Instruments, and Systems, On-ground calibration of the Hitomi Hard X-ray Telescopes, Hideyuki Mori; Takuya Miyazawa; Hisamitsu Awaki; Hironori Matsumoto; Yasunori Babazaki; Ayako Bandai; Tadatsugu Demoto; Akihiro Furuzawa; Yoshito Haba; Takayuki Hayashi; Ryo Iizuka; Kazunori Ishibashi; Manabu Ishida; Naoki Ishida; Masayuki Itoh; Toshihiro Iwase; Hiroyoshi Kato; Hiroaki Kobayashi; Tatsuro Kosaka; Hideyo Kunieda; Shou Kurashima; Daichi Kurihara; Yuuji Kuroda; Yoshitomo Maeda; Yoshifumi Meshino; Ikuyuki Mitsuishi; Yuusuke Miyata; Housei Nagano; Yoshiharu Namba; Yasushi Ogasaka; Keiji Ogi; Takashi Okajima; Shigetaka Saji; Fumiya Shimasaki; Takuro Sato; Toshiki Sato; Naotsugu Shima; Satoshi Sugita; Yoshio Suzuki; Kenji Tachibana; Sasagu Tachibana; Shun'Ya Takizawa; Keisuke Tamura; Yuzuru Tawara; Kazuki Tomikawa; Tatsuharu Torii; Kentaro Uesugi; Koujun Yamashita; Shigeo Yamauchi, © 2018 The Authors. We present x-ray characteristics of the Hard X-ray Telescopes (HXTs) on board the Hitomi (ASTRO-H) satellite. Measurements were conducted at the SPring-8 BL20B2 beamline and the ISAS/JAXA 27-m beamline. The angular resolution defined by a half-power diameter was 1.9′ (HXT-1) and 2.1′ (HXT-2) at 8 keV, 1.9′ at 30 keV, and 1.8′ at 50 keV. The effective area was found to be 620cm2 at 8 keV, 178cm2 at 30 keV, and 82cm2 at 50 keV per mirror module. Although the angular resolutions were slightly worse than the requirement (1.7′), the effective areas sufficiently exceeded the requirements of 150cm2 at 30 keV and 55cm2 at 50 keV. The off-axis measurements of the effective areas resulted in the field of view being 6.1′ at 50 keV, 7.7′ at 30 keV, and 9.7′ at 8 keV in diameter. We confirmed that the main component of the stray x-ray light was significantly reduced by mounting the precollimator as designed. Detailed analysis of the data revealed that the angular resolution was degraded mainly by figure errors of mirror foils, and the angular resolution is completely explained by the figure errors, positioning errors of the foils, and conical approximation of the foil shape. We found that the effective areas were ∼80% of the designed values below 40 keV, whereas they steeply decline above 40 keV and become only ∼50%. We investigated this abrupt decline and found that neither the error of the multilayer design nor the errors of the incident angles induced by the positioning errors of the foils can be the cause. The reflection profile of each foil pair from the defocused image strongly suggests that the figure errors of the foils probably bring about the reduction in the effective areas at higher energies., 01 Jan. 2018, 4, 1, 011210, Scientific journal, 10.1117/1.JATIS.4.1.011210

Refereed, Journal of Astronomical Telescopes, Instruments, and Systems, SPIE, Inorbit performance of the Hard X-ray Telescope (HXT) on board the Hitomi (ASTRO-H) satellite, Hironori Matsumoto; Hisamitsu Awaki; Manabu Ishida; Akihiro Furuzawa; Shigeo Yamauchi; Yoshitomo Maeda; Ikuyuki Mitsuishi; Yoshito Haba; Takayuki Hayashi; Ryo Iizuka; Kazunori Ishibashi; Masayuki Itoh; Hideyo Kunieda; Takuya Miyazawa; Hideyuki Mori; Takashi Okajima; Satoshi Sugita; Keisuke Tamura; Yuzuru Tawara, Hitomi (ASTRO-H) carries two Hard X-ray Telescopes (HXTs), which can focus x-rays up to 80 keV. Combined with the hard x-ray imagers (HXIs) that detect the focused x-rays, imaging spectroscopy in the high-energy band from 5 to 80 keV is made possible. We studied characteristics of HXTs after the launch, such as the encircled energy function (EEF) and the effective area using the data of a Crab observation. The half power diameters (HPDs) in the 5- to 80-keV band evaluated from the EEFs are 1.59 arcmin for HXT-1 and 1.65 arcmin for HXT-2. Those are consistent with the HPDs measured with ground experiments when uncertainties are taken into account. We can conclude that there is no significant change in the characteristics of the HXTs before and after the launch. The off-axis angle of the aim point from the optical axis is evaluated to be < 0.5 arcmin for both HXT-1 and HXT-2. The best-fit parameters for the Crab spectrum obtained with the HXT-HXI system are consistent with the canonical values., 01 Jan. 2018, 4, 1, 011212, Scientific journal, 10.1117/1.JATIS.4.1.011212

Refereed, NATURE, NATURE PUBLISHING GROUP, Solar abundance ratios of the iron-peak elements in the Perseus cluster, Felix Aharonian; Hiroki Akamatsu; Fumie Akimoto; Steven W. Allen; Lorella Angelini; Marc Audard; Hisamitsu Awaki; Magnus Axelsson; Aya Bamba; Marshall W. Bautz; Roger Blandford; Laura W. Brenneman; Gregory V. Brown; Esra Bulbul; Edward M. Cackett; Maria Chernyakova; Meng P. Chiao; Paolo S. Coppi; Elisa Costantini; Jelle De Plaa; Jan-Willem den Herder; Chris Done; Tadayasu Dotani; Ken Ebisawa; Megan E. Eckart; Teruaki Enoto; Yuichiro Ezoe; Andrew C. Fabian; Carlo Ferrigno; Adam R. Foster; Ryuichi Fujimoto; Yasushi Fukazawa; Akihiro Furuzawa; Massimiliano Galeazzi; Luigi C. Gallo; Poshak Gandhi; Margherita Giustini; Andrea Goldwurm; Liyi Gu; Matteo Guainazzi; Yoshito Haba; Kouichi Hagino; Kenji Hamaguchi; Ilana M. Harrus; Isamu Hatsukade; Katsuhiro Hayashi; Takayuki Hayashi; Kiyoshi Hayashida; Junko S. Hiraga; Ann Hornschemeier; Akio Hoshino; John P. Hughes; Yuto Ichinohe; Ryo Iizuka; Hajime Inoue; Yoshiyuki Inoue; Manabu Ishida; Kumi Ishikawa; Yoshitaka Ishisaki; Masachika Iwai; Jelle Kaastra; Tim Kallman; Tsuneyoshi Kamae; Jun Kataoka; Satoru Katsuda; Nobuyuki Kawai; Richard L. Kelley; Caroline A. Kilbourne; Takao Kitaguchi; Shunji Kitamoto; Tetsu Kitayama; Takayoshi Kohmura; Motohide Kokubun; Katsuji Koyama; Shu Koyama; Peter Kretschmar; Hans A. Krimm; Aya Kubota; Hideyo Kunieda; Philippe Laurent; Shiu-Hang Lee; Maurice A. Leutenegger; Olivier Limousine; Michael Loewenstein; Knox S. Long; David Lumb; Greg Madejski; Yoshitomo Maeda; Daniel Maier; Kazuo Makishima; Maxim Markevitch; Hironori Matsumoto; Kyoko Matsushita; Dan McCammon; Brian R. McNamara; Missagh Mehdipour; Eric D. Miller; Jon M. Miller; Shin Mineshige; Kazuhisa Mitsuda; Ikuyuki Mitsuishi; Takuya Miyazawa; Tsunefumi Mizuno; Hideyuki Mori; Koji Mori; Koji Mukai; Hiroshi Murakami; Richard F. Mushotzky; Takao Nakagawa; Hiroshi Nakajima; Takeshi Nakamori; Shinya Nakashima; Kazuhiro Nakazawa; Kumiko K. Nobukawa; Masayoshi Nobukawa; Hirofumi Noda; Hirokazu Odaka; Takaya Ohashi; Masanori Ohno; Takashi Okajima; Naomi Ota; Masanobu Ozaki; Frits Paerels; StPhane Paltani; Robert Petre; Ciro Pinto; Frederick S. Porter; Katja Pottschmidt; Christopher S. Reynolds; Samar Safi-Harb; Shinya Saito; Kazuhiro Sakai; Toru Sasaki; Goro Sato; Kosuke Sato; Rie Sato; Makoto Sawada; Norbert Schartel; Peter J. Serlemitsos; Hiromi Seta; Megumi Shidatsu; Aurora Simionescu; Randall K. Smith; Yang Soong; Lukasz Stawarz; Yasuharu Sugawara; Satoshi Sugita; Andrew Szymkowiak; Hiroyasu Tajima; Hiromitsu Takahashi; Tadayuki Takahashi; Shin'ichiro Takeda; Yoh Takei; Toru Tamagawa; Takayuki Tamura; Takaaki Tanaka; Yasuo Tanaka; Yasuyuki T. Tanaka; Makoto S. Tashiro; Yuzuru Tawara; Yukikatsu Terada; Yuichi Terashima; Francesco Tombesi; Hiroshi Tomida; Yohko Tsuboi; Masahiro Tsujimoto; Hiroshi Tsunemi; Takeshi Go Tsuru; Hiroyuki Uchida; Hideki Uchiyama; Yasunobu Uchiyama; Shutaro Ueda; Yoshihiro Ueda; Shin'ichiro Uno; C. Megan Urry; Eugenio Ursino; Cor P. de Vries; Shin Watanabe; Norbert Werner; Daniel R. Wik; Dan R. Wilkins; Brian J. Williams; Shinya Yamada; Hiroya Yamaguchi; Kazutaka Yamaoka; Noriko Y. Yamasaki; Makoto Yamauchi; Shigeo Yamauchi; Tahir Yaqoob; Yoichi Yatsu; Daisuke Yonetoku; Irina Zhuravleva; Abderahmen Zoghbi, The metal abundance of the hot plasma that permeates galaxy clusters represents the accumulation of heavy elements produced by billions of supernovae(1). Therefore, X-ray spectroscopy of the intracluster medium provides an opportunity to investigate the nature of supernova explosions integrated over cosmic time. In particular, the abundance of the iron-peak elements (chromium, manganese, iron and nickel) is key to understanding how the progenitors of typical type Ia supernovae evolve and explode(2-6). Recent X-ray studies of the intracluster medium found that the abundance ratios of these elements differ substantially from those seen in the Sun(7-11), suggesting differences between the nature of type Ia supernovae in the clusters and in the Milky Way. However, because the K-shell transition lines of chromium and manganese are weak and those of iron and nickel are very close in photon energy, highresolution spectroscopy is required for an accurate determination of the abundances of these elements. Here we report observations of the Perseus cluster, with statistically significant detections of the resonance emission from chromium, manganese and nickel. Our measurements, combined with the latest atomic models, reveal that these elements have near-solar abundance ratios with respect to iron, in contrast to previous claims. Comparison between our results and modern nucleosynthesis calculations(12-14) disfavours the hypothesis that type Ia supernova progenitors are exclusively white dwarfs with masses well below the Chandrasekhar limit (about 1.4 times the mass of the Sun). The observed abundance pattern of the iron-peak elements can be explained by taking into account a combination of near-and sub-Chandrasekhar-mass type Ia supernova systems, adding to the mounting evidence that both progenitor types make a substantial contribution to cosmic chemical enrichment(5,15,16)., Nov. 2017, 551, 7681, 478, +, Scientific journal, 10.1038/nature24301

Refereed, ASTROPHYSICAL JOURNAL LETTERS, IOP PUBLISHING LTD, Hitomi Constraints on the 3.5 keV Line in the Perseus Galaxy Cluster, F. A. Aharonian; H. Akamatsu; F. Akimoto; S. W. Allen; L. Angelini; K. A. Arnaud; M. Audard; H. Awaki; M. Axelsson; A. Bamba; M. W. Bautz; R. D. Blandford; E. Bulbul; L. W. Brenneman; G. V. Brown; E. M. Cackett; M. Chernyakova; M. P. Chiao; P. Coppi; E. Costantini; J. de Plaa; J. -W. den Herder; C. Done; T. Dotani; K. Ebisawa; M. E. Eckart; T. Enoto; Y. Ezoe; A. C. Fabian; C. Ferrigno; A. R. Foster; R. Fujimoto; Y. Fukazawa; A. Furuzawa; M. Galeazzi; L. C. Gallo; P. Gandhi; M. Giustini; A. Goldwurm; L. Gu; M. Guainazzi; Y. Haba; K. Hagino; K. Hamaguchi; I. Harrus; I. Hatsukade; K. Hayashi; T. Hayashi; K. Hayashida; J. Hiraga; A. E. Hornschemeier; A. Hoshino; J. P. Hughes; Y. Ichinohe; R. Iizuka; H. Inoue; S. Inoue; Y. Inoue; K. Ishibashi; M. Ishida; K. Ishikawa; Y. Ishisaki; M. Itoh; M. Iwai; N. Iyomoto; J. S. Kaastra; T. Kallman; T. Kamae; E. Kara; J. Kataoka; S. Katsuda; J. Katsuta; M. Kawaharada; N. Kawai; R. L. Kelley; D. Khangulyan; C. A. Kilbourne; A. L. King; T. Kitaguchi; S. Kitamoto; T. Kitayama; T. Kohmura; M. Kokubun; S. Koyama; K. Koyama; P. Kretschmar; H. A. Krimm; A. Kubota; H. Kunieda; P. Laurent; F. Lebrun; S. -H. Lee; M. A. Leutenegger; O. Limousin; M. Loewenstein; K. S. Long; D. H. Lumb; G. M. Madejski; Y. Maeda; D. Maier; K. Makishima; M. Markevitch; H. Matsumoto; K. Matsushita; D. McCammon; B. R. McNamara; M. Mehdipour; E. D. Miller; J. M. Miller; S. Mineshige; K. Mitsuda; I. Mitsuishi; T. Miyazawa; T. Mizuno; H. Mori; K. Mori; H. Moseley; K. Mukai; H. Murakami; T. Murakami; R. F. Mushotzky; T. Nakagawa; H. Nakajima; T. Nakamori; T. Nakano; S. Nakashima; K. Nakazawa; K. Nobukawa; M. Nobukawa; H. Noda; M. Nomachi; S. L. O'Dell; H. Odaka; T. Ohashi; M. Ohno; T. Okajima; N. Ota; M. Ozaki; F. Paerels; S. Paltani; A. Parmar; R. Petre; C. Pinto; M. Pohl; F. S. Porter; K. Pottschmidt; B. D. Ramsey; C. S. Reynolds; H. R. Russell; S. Safi-Harb; S. Saito; K. Sakai; H. Sameshima; T. Sasaki; G. Sato; K. Sato; R. Sato; M. Sawada; N. Schartel; P. J. Serlemitsos; H. Seta; M. Shidatsu; A. Simionescu; R. K. Smith; Y. Soong; L. Stawarz; Y. Sugawara; S. Sugita; A. E. Szymkowiak; H. Tajima; H. Takahashi; T. Takahashi; S. Takeda; Y. Takei; T. Tamagawa; K. Tamura; T. Tamura; T. Tanaka; Yasuo Tanaka; Yasuyuki Tanaka; M. Tashiro; Y. Tawara; Y. Terada; Y. Terashima; F. Tombesi; H. Tomida; Y. Tsuboi; M. Tsujimoto; H. Tsunemi; T. Tsuru; H. Uchida; H. Uchiyama; Y. Uchiyama; S. Ueda; Y. Ueda; S. Ueno; S. Uno; C. M. Urry; E. Ursino; C. P. de Vries; S. Watanabe; N. Werner; D. R. Wik; D. R. Wilkins; B. J. Williams; S. Yamada; H. Yamaguchi; K. Yamaoka; N. Y. Yamasaki; M. Yamauchi; S. Yamauchi; T. Yaqoob; Y. Yatsu; D. Yonetoku; A. Yoshida; I. Zhuravleva; A. Zoghbi, X-ray spectroscopy with Hitomi was expected to resolve the origin of the faint unidentified E approximate to 3.5 keV emission line reported in several low-resolution studies of various massive systems, such as galaxies and clusters, including the Perseus cluster. We have analyzed the Hitomi first-light observation of the Perseus cluster. The emission line expected for Perseus based on the XMM-Newton signal from the large cluster sample under the dark matter decay scenario is too faint to be detectable in the Hitomi data. However, the previously reported 3.5 keV flux from Perseus was anomalously high compared to the sample-based prediction. We find no unidentified line at the reported high flux level. Taking into account the XMM measurement uncertainties for this region, the inconsistency with Hitomi is at a 99% significance for a broad dark matter line and at 99.7% for a narrow line from the gas. We do not find anomalously high fluxes of the nearby faint K line or the Ar satellite line that were proposed as explanations for the earlier 3.5 keV detections. We do find a hint of a broad excess near the energies of high-n transitions of S XVI (E similar or equal to 3.44 keV rest-frame)-a possible signature of charge exchange in the molecular nebula and another proposed explanation for the unidentified line. While its energy is consistent with XMM pn detections, it is unlikely to explain the MOS signal. A confirmation of this interesting feature has to wait for a more sensitive observation with a future calorimeter experiment., Mar. 2017, 837, 1, L15 (9 pages), Scientific journal, 10.3847/2041-8213/aa61fa

Not Refereed, OPTICS FOR EUV, X-RAY, AND GAMMA-RAY ASTRONOMY VIII, SPIE-INT SOC OPTICAL ENGINEERING, The Hitomi (ASTRO-H) Hard X-ray Telescope (HXT) : current status of calibration, Hisamitsu Awaki; Hironori Matsumoto; Manabu Ishida; Akihiro Furuzawa; Shigeo Yamauchi; Yoshitomo Maeda; Hideyo Kunieda; Yoshito Haba; Takayuki Hayashi; Ryo Iizuka; Kazunori Ishibashi; Ikuyuki Mitsuishi; Takuya Miyazawa; Hideyuki Mori; Takashi Okajima; Satoshi Sugita; Keisuke Tamura; Yuzuru Tawara; Tessei Yoshida, The Japanese X-ray Astronomy Satellite, Hitomi (ASTRO-H) carried two hard X-ray telescopes (HXT), covering the energy band from 5 keV to 80 keV. In the initial functional verification phase of the onboard instruments, G21.5-0.9 and Crab nebula were observed with HXT. The data of G21.5-0.9 observation indicated that the hard X-ray imaging system worked well. Detail calibration of the Hitomi HXTs was performed with the observation data of Crab nebula. We extracted X-ray images of the Crab pulsar excluding the nebular emission, and continued that the imaging perfounance in orbit was satisfied with the requirement of the HXT. The 8-80 keV Crab spectrum was well fitted with a power-law model with the absorbed column of N-H=3 x 10(21) cm(-2). The estimated photon index of 2.122 0.003 was consistent with previous results of Crab observation, while the observed 2-10 keV flux of 2.3x10-8 erg s(-1) cm(-2) was slightly larger than the previous observation. We note that there was discrepancy between the simulated and the measured effective area on ground. Thus, we introduced a fudge factor to reproduce the effective area obtained in the ground calibration. The fudge factor of HXTs are included in the latest calibration database of Hitomi., 2017, 10399, id. 103990R, International conference proceedings, 10.1117/12.2272844

Refereed, ASTROPHYSICAL JOURNAL, IOP PUBLISHING LTD, ORIGIN OF THE GALACTIC DIFFUSE X-RAY EMISSION: IRON K-SHELL LINE DIAGNOSTICS, Masayoshi Nobukawa; Hideki Uchiyama; Kumiko K. Nobukawa; Shigeo Yamauchi; Katsuji Koyama, This paper reports detailed K-shell line profiles of iron (Fe) and nickel (Ni) of the Galactic Center X-ray Emission (GCXE), Galactic Bulge X-ray Emission (GBXE), Galactic Ridge X-ray Emission (GRXE), magnetic Cataclysmic Variables (mCVs), non-magnetic Cataclysmic Variables (non-mCVs), and coronally Active Binaries (ABs). For the study of the origin of the GCXE, GBXE, and GRXE, the spectral analysis is focused on equivalent widths of the Fe I-K alpha, Fe XXV-He alpha, and Fe XXVI-Ly alpha. lines. The global spectrum of the GBXE is reproduced by a combination of the mCVs, non-mCVs, and ABs spectra. On the other hand, the GRXE spectrum shows significant data excesses at the Fe I-Ka and Fe XXV-Hea. line energies. This means that additional components other than mCVs, non-mCVs, and ABs are required, which have symbiotic phenomena of cold gas and very high-temperature plasma. The GCXE spectrum shows larger excesses than those found in the GRXE spectrum at all the K-shell lines of iron and nickel. Among them the largest ones are the Fe I-K alpha, Fe XXV-He alpha, Fe XXVI-Ly alpha, and Fe XXVI-Ly beta. lines. Together with the fact that the scale heights of the Fe I-K alpha, Fe XXV-He alpha, and Fe XXVI-Ly alpha lines are similar to that of the central molecular zone (CMZ), the excess components would be related to high-energy activity in the extreme envelopment of the CMZ., Dec. 2016, 833, 2, 268 (10 pages), Scientific journal, 10.3847/1538-4357/833/2/268

Refereed, PUBLICATIONS OF THE ASTRONOMICAL SOCIETY OF JAPAN, OXFORD UNIV PRESS, Scale heights and equivalent widths of the iron K-shell lines in the Galactic diffuse X-ray emission, Shigeo Yamauchi; Kumiko K. Nobukawa; Masayoshi Nobukawa; Hideki Uchiyama; Katsuji Koyama, This paper reports the analysis of the X-ray spectra of the Galactic diffuse X-ray emission (GDXE) in the Suzaku archive. The fluxes of the Fe I K alpha (6.4 keV), Fe XXV He alpha (6.7 keV), and Fe XXVI Ly alpha (6.97 keV) lines are separately determined. From the latitude distributions, we confirm that the GDXE is decomposed into the Galactic center (GCXE), the Galactic bulge (GBXE) and the Galactic ridge (GRXE) X-ray emissions. The scale heights (SHs) of the Fe XXV He alpha line of the GCXE, GBXE, and GRXE are determined to be similar to 40, similar to 310, and similar to 140 pc, while those of the Fe I K alpha line are similar to 30, similar to 160, and similar to 70 pc, respectively. The mean equivalent widths (EWs) of the sum of the Fe XXV He alpha and Fe XXVI Lya lines are similar to 750 eV, similar to 600 eV, and similar to 550 eV, while those of the Fe I K alpha line are similar to 150 eV, similar to 60 eV, and similar to 100 eV for the GCXE, GBXE, and GRXE, respectively. The origin of the GBXE, GRXE, and GCXE is separately discussed based on the new results of the SHs and EWs, in comparison with those of the cataclysmic variables, active binaries and coronal active stars., Aug. 2016, 68, 4, 59 (13 pages), Scientific journal, 10.1093/pasj/psw057

Refereed, NATURE, NATURE PUBLISHING GROUP, The quiescent intracluster medium in the core of the Perseus cluster, Felix Aharonian; Hiroki Akamatsu; Fumie Akimoto; Steven W. Allen; Naohisa Anabuki; Lorella Angelini; Keith Arnaud; Marc Audard; Hisamitsu Awaki; Magnus Axelsson; Aya Bamba; Marshall Bautz; Roger Blandford; Laura Brenneman; Gregory V. Brown; Esra Bulbul; Edward Cackett; Maria Chernyakova; Meng Chiao; Paolo Coppi; Elisa Costantini; Jelle de Plaa; Jan-Willem den Herder; Chris Done; Tadayasu Dotani; Ken Ebisawa; Megan Eckart; Teruaki Enoto; Yuichiro Ezoe; Andrew C. Fabian; Carlo Ferrigno; Adam Foster; Ryuichi Fujimoto; Yasushi Fukazawa; Akihiro Furuzawa; Massimiliano Galeazzi; Luigi Gallo; Poshak Gandhi; Margherita Giustini; Andrea Goldwurm; Liyi Gu; Matteo Guainazzi; Yoshito Haba; Kouichi Hagino; Kenji Hamaguchi; Ilana Harrus; Isamu Hatsukade; Katsuhiro Hayashi; Takayuki Hayashi; Kiyoshi Hayashida; Junko Hiraga; Ann Hornschemeier; Akio Hoshino; John Hughes; Ryo Iizuka; Hajime Inoue; Yoshiyuki Inoue; Kazunori Ishibashi; Manabu Ishida; Kumi Ishikawa; Yoshitaka Ishisaki; Masayuki Itoh; Naoko Iyomoto; Jelle Kaastra; Timothy Kallman; Tuneyoshi Kamae; Erin Kara; Jun Kataoka; Satoru Katsuda; Junichiro Katsuta; Madoka Kawaharada; Nobuyuki Kawai; Richard Kelley; Dmitry Khangulyan; Caroline Kilbourne; Ashley King; Takao Kitaguchi; Shunji Kitamoto; Tetsu Kitayama; Takayoshi Kohmura; Motohide Kokubun; Shu Koyama; Katsuji Koyama; Peter Kretschmar; Hans Krimm; Aya Kubota; Hideyo Kunieda; Philippe Laurent; Francois Lebrun; Shiu-Hang Lee; Maurice Leutenegger; Olivier Limousin; Michael Loewenstein; Knox S. Long; David Lumb; Grzegorz Madejski; Yoshitomo Maeda; Daniel Maier; Kazuo Makishima; Maxim Markevitch; Hironori Matsumoto; Kyoko Matsushita; Dan McCammon; Brian McNamara; Missagh Mehdipour; Eric Miller; Jon Miller; Shin Mineshige; Kazuhisa Mitsuda; Ikuyuki Mitsuishi; Takuya Miyazawa; Tsunefumi Mizuno; Hideyuki Mori; Koji Mori; Harvey Moseley; Koji Mukai; Hiroshi Murakami; Toshio Murakami; Richard Mushotzky; Ryo Nagino; Takao Nakagawa; Hiroshi Nakajima; Takeshi Nakamori; Toshio Nakano; Shinya Nakashima; Kazuhiro Nakazawa; Masayoshi Nobukawa; Hirofumi Noda; Masaharu Nomachi; Steve O'Dell; Hirokazu Odaka; Takaya Ohashi; Masanori Ohno; Takashi Okajima; Naomi Ota; Masanobu Ozaki; Frits Paerels; Stephane Paltani; Arvind Parmar; Robert Petre; Ciro Pinto; Martin Pohl; F. Scott Porter; Katja Pottschmidt; Brian Ramsey; Christopher Reynolds; Helen Russell; Samar Safi-Harb; Shinya Saito; Kazuhiro Sakai; Hiroaki Sameshima; Goro Sato; Kosuke Sato; Rie Sato; Makoto Sawada; Norbert Schartel; Peter Serlemitsos; Hiromi Seta; Megumi Shidatsu; Aurora Simionescu; Randall Smith; Yang Soong; Lukasz Stawarz; Yasuharu Sugawara; Satoshi Sugita; Andrew Szymkowiak; Hiroyasu Tajima; Hiromitsu Takahashi; Tadayuki Takahashi; Shin'ichiro Takeda; Yoh Takei; Toru Tamagawa; Keisuke Tamura; Takayuki Tamura; Takaaki Tanaka; Yasuo Tanaka; Yasuyuki Tanaka; Makoto Tashiro; Yuzuru Tawara; Yukikatsu Terada; Yuichi Terashima; Francesco Tombesi; Hiroshi Tomida; Yohko Tsuboi; Masahiro Tsujimoto; Hiroshi Tsunemi; Takeshi Tsuru; Hiroyuki Uchida; Hideki Uchiyama; Yasunobu Uchiyama; Shutaro Ueda; Yoshihiro Ueda; Shiro Ueno; Shin'ichiro Uno; Meg Urry; Eugenio Ursino; Cor De Vries; Shin Watanabe; Norbert Werner; Daniel Wik; Dan Wilkins; Brian Williams; Shinya Yamada; Hiroya Yamaguchi; Kazutaka Yamaoka; Noriko Y. Yamasaki; Makoto Yamauchi; Shigeo Yamauchi; Tahir Yaqoob; Yoichi Yatsu; Daisuke Yonetoku; Atsumasa Yoshida; Takayuki Yuasa; Irina Zhuravleva; Abderahmen Zoghbi, Clusters of galaxies are the most massive gravitationally bound objects in the Universe and are still forming. They are thus important probes(1) of cosmological parameters and many astrophysical processes. However, knowledge of the dynamics of the pervasive hot gas, the mass of which is much larger than the combined mass of all the stars in the cluster, is lacking. Such knowledge would enable insights into the injection of mechanical energy by the central supermassive black hole and the use of hydrostatic equilibrium for determining cluster masses. X-rays from the core of the Perseus cluster are emitted by the 50-million-kelvin diffuse hot plasma filling its gravitational potential well. The active galactic nucleus of the central galaxy NGC 1275 is pumping jetted energy into the surrounding intracluster medium, creating buoyant bubbles filled with relativistic plasma. These bubbles probably induce motions in the intracluster medium and heat the inner gas, preventing runaway radiative cooling-a process known as active galactic nucleus feedback(2-6). Here we report X-ray observations of the core of the Perseus cluster, which reveal a remarkably quiescent atmosphere in which the gas has a line-of-sight velocity dispersion of 164 +/- 10 kilometres per second in the region 30-60 kiloparsecs from the central nucleus. A gradient in the line-of-sight velocity of 150 +/- 70 kilometres per second is found across the 60-kiloparsec image of the cluster core. Turbulent pressure support in the gas is four per cent of the thermodynamic pressure, with large-scale shear at most doubling this estimate. We infer that a total cluster mass determined from hydrostatic equilibrium in a central region would require little correction for turbulent pressure., Jul. 2016, 535, 7610, 117, +, Scientific journal, 10.1038/nature18627

Refereed, PUBLICATIONS OF THE ASTRONOMICAL SOCIETY OF JAPAN, OXFORD UNIV PRESS, Suzaku observations of two diffuse hard X-ray source regions, G22.0+0.0 and G23.5+0.1, Shigeo Yamauchi; Mayu Sumita; Aya Bamba, G22.0+0.0 and G23.5+0.1 are diffuse hard X-ray sources discovered in the ASCA Galactic Plane Survey. We present Suzaku results of spectral analysis for these sources. G22.0+0.0 is confirmed to be a largely extended emission. Its spectra were represented by a highly absorbed power-law model with a photon index of 1.7 +/- 0.3 and a moderately absorbed thermal emission with a temperature of 0.34(-0.08)(+0.11) keV. The difference in the N-H values between the two components suggests that the thermal component is unrelated to the power-law component and is a foreground emission located in the same line of sight. G23.5+0.1 is an extended source with a size of similar to 3.'5. Its spectra were fitted with an absorbed power-law model with a photon index of 2.4(-0.4)(+0.5). The spatial and spectral properties show that both sources are candidates for old pulsar wind nebulae (PWNe). In addition to the extended sources, we analyzed spectra of three point sources found in the observed fields. Based on the spectral features, we discuss the origin of the sources., Jun. 2016, 68, SP1, S6 (10 pages), Scientific journal, 10.1093/pasj/psv109

Refereed, PUBLICATIONS OF THE ASTRONOMICAL SOCIETY OF JAPAN, OXFORD UNIV PRESS, Iron emission line from the spiral galaxy M101, Shigeo Yamauchi, Archival Suzaku data of the face-on spiral galaxy M101 were analyzed. An intense emission line at 6.72(-0.12)(+0.10) keV was detected in the central region. This line is identified with a K-line from He-like iron, which indicates the existence of a thin thermal plasma with a temperature of several keV. The iron line luminosity within the central 5'-radius region is estimated to be (2-12) x 10(37) erg s(-1). The origin of the iron emission line is discussed., Jun. 2016, 68, SP1, S18 (9 pages), Scientific journal, 10.1093/pasj/psv107

Not Refereed, eprint arXiv 1412.1170, eprint arXiv, ASTRO-H White Paper - Plasma Diagnostic and Dynamics of the Galactic Center Region, Koyama, K; Kataoka, J; Nobukawa, M; Uchiyama, H; Nakashima, S; Aharonian, F; Chernyakova, M; Ichinohe, Y; Nobukawa, K. K; Maeda, Y; Matsumoto, H; Murakami, H; Ricci, C; Stawarz, L; Tanaka, T; Tsuru, T. G; Watanabe, S; Yamauchi, S; Yuasa, T; for the ASTRO-H; Science Working Group, 01 Dec. 2014, Scientific journal

Refereed, PUBLICATIONS OF THE ASTRONOMICAL SOCIETY OF JAPAN, OXFORD UNIV PRESS, X-ray filament with a strong 6.7-keV line in the Galactic center region, Shigeo Yamauchi; Miku Shimizu; Shinya Nakashima; Masayoshi Noaukawa; Takeshi Go Tsuru; Katsuji Koyama, An elongated X-ray source with a strong K-shell line from He-like iron (Fe XXVI) is found at (RA, Dec)(J2000.0) = (17(h)44(m)00.(s)0, -29 degrees 13'40 ''.9) in the Galactic center region. The position coincides with the X-ray thread, G359.55+0.16, which is aligned with the radio non-thermal filament. The X-ray spectrum is well fitted with an absorbed thin thermal plasma (apec) model. The best-fitting temperature, metal abundance, and column density are 4.1(-1.8)(+2.7) keV, 0.58(-0.32)(+0.41) solar, and 6.1(-1.3)(+2.5) x 10(22) cm(-2), respectively. These values are similar to those of the largely extended Galactic center X-ray emission., Dec. 2014, 66, 6, 125 (6 pages), Scientific journal, 10.1093/pasj/psu122

Refereed, Applied Optics, Hard x-ray telescopes to be onboard ASTRO-H, Hisamitsu Awaki; Hideyo Kunieda; Manabu Ishida; Hironori Matsumoto; Yasunori Babazaki; Tadatsugu Demoto; Akihiro Furuzawa; Yoshito Haba; Takayuki Hayashi; Ryo Iizuka; Kazunori Ishibashi; Naoki Ishida; Masayuki Itoh; Toshihiro Iwase; Tatsuro Kosaka; Daichi Kurihara; Yuuji Kuroda; Yoshitomo Maeda; Yoshifumi Meshino; Ikuyuki Mitsuishi; Yuusuke Miyata; Takuya Miyazawa; Hideyuki Mori; Housei Nagano; Yoshiharu Namba; Yasushi Ogasaka; Keiji Ogi; Takashi Okajima; Shigetaka Saji; Fumiya Shimasaki; Takuro Sato; Toshiki Sato; Satoshi Sugita; Yoshio Suzuki; Kenji Tachibana; Sasagu Tachibana; Shunya Takizawa; Keisuke Tamura; Yuzuru Tawara; Tatsuharu Torii; Kentato Uesugi; Koujun Yamashita; Shigeo Yamauchi, © 2014 Optical Society of America. The new Japanese x-ray astronomy satellite, ASTRO-H, will carry two identical hard x-ray telescopes (HXTs), which cover the energy range of 5 to 80 keV. The HXT mirrors employ tightly nested, conically approximated thin-foil Wolter-I optics, and the mirror surfaces are coated with Pt/C depth-graded multilayers to enhance the hard x-ray effective area by means of Bragg reflection. The HXT comprises foils 120-450 mm in diameter and 200 mm in length, with a focal length of 12 m. To obtain a large effective area, 213 aluminum foils 0.2 mm in thickness are tightly nested confocally. The requirements for HXT are a total effective area of >300 cm2 at 30 keV and an angular resolution of <1.70 in halfpower diameter (HPD). Fabrication of two HXTs has been completed, and the x-ray performance of each HXT was measured at a synchrotron radiation facility, SPring-8 BL20B2 in Japan. Angular resolutions (HPD) of 1.9′ and 1.8′ at 30 keV were obtained for the full telescopes of HXT-1 and HXT-2, respectively. The total effective area of the two HXTs at 30 keV is 349 cm2., 10 Nov. 2014, 53, 32, 7664, 7676, Scientific journal, 10.1364/AO.53.007664

Refereed, PUBLICATIONS OF THE ASTRONOMICAL SOCIETY OF JAPAN, OXFORD UNIV PRESS, Thermal and non-thermal X-rays from the Galactic supernova remnant G348.5+0.1, Shigeo Yamauchi; Sari Minami; Naomi Ota; Katsuji Koyama, We report on Suzaku results of the two distinct regions in the Galactic supernova remnant G348.5+0.1: extended thermal X-rays ("soft diffuse") at the north-east region and non-thermal X-rays (CXOU J171419.8-383023) at the north-west region. The X-ray spectrum of the soft diffuse X-rays can be fitted with neither an ionization equilibrium nor a non-equilibrium (ionizing) plasma model, leaving saw-tooth residuals in the 1.5-3 keV energy band. The residual structures can be produced when free electrons are recombined to the K-shells of highly ionized Mg and Si ions. In fact, the X-ray spectrum is nicely fitted with a recombination-dominant plasma model. We propose a scenario whereby the plasma in a nearly fully ionized state at high temperature quickly changed to a recombining phase due to selective cooling of electrons to a lower temperature of similar to 0.5 keV. The spectrum of CXOU J171419.8-383023 is well explained by a simple power-law model with a photon index of 1.9, nearly equal to the typical value for pulsar wind nebulae. Since the distance is estimated to be the same as that of the soft diffuse radiation, we infer that both the soft diffuse X-rays and CXOU J171419.8-383023 are associated with the same object, SNR G348.5+0.1., Feb. 2014, 66, 1, 2 (7 pages), Scientific journal, 10.1093/pasj/pst004

Refereed, PUBLICATIONS OF THE ASTRONOMICAL SOCIETY OF JAPAN, OXFORD UNIV PRESS, X-ray emission from the galactic supernova remnant G12.0-0.1, Shigeo Yamauchi; Aya Bamba; Katsuji Koyama, We present results of the Suzaku/XIS observation around the radio supernova remnant (SNR) G12.0-0.1. No significant diffuse emission extending in or along the radio shell was observed. Instead, two compact X-ray sources, Suzaku J181205-1835 and Suzaku J181210-1842, were found in or near G12.0-0.1. Suzaku J181205-1835 is located at the north-west of the radio shell of G12.0-0.1. The X-ray profile is slightly extended over the point spread function of the Suzaku telescope. The X-ray spectrum has no line-like structure and is well represented by a power-law model with a photon index of 2.2 and an absorption column of N-H = 4.9 x 10(22) cm(-2). The distances of Suzaku J181205-1835 and G12.0-0.1 are estimated from the absorption column and the I aEuro"D pound relation, respectively, and are nearly the same as each other. These results suggest that Suzaku J181205-1835 is a candidate for a pulsar wind nebula associated with G12.0-0.1. From its location, Suzaku J181210-1842 is expected to be unrelated to G12.0-0.1. The X-ray profile is point-like and the spectrum shows thin thermal emission with Fe K-lines at 6.4, 6.7, and 6.97 keV, similar to those of cataclysmic variables., Feb. 2014, 66, 1, 20 (8 pages), Scientific journal, 10.1093/pasj/pst021

Refereed, PUBLICATIONS OF THE ASTRONOMICAL SOCIETY OF JAPAN, OXFORD UNIV PRESS, X-Ray Observation of the Galactic Supernova Remnant G355.6-0.0 with Suzaku, Sari Minami; Naomi Ota; Shigeo Yamauchi; Katsuji Koyama, We present results of the Galactic supernova remnant (SNR) G355.6-0.0 observed with Suzaku. We resolved diffuse emission detected with ASCA into two objects, G355.6-0.0 and a point-like source, Suzaku J173530-3236. The X-ray emission from G355.6-0.0 exhibits a center-filled morphology within the radio shell. The X-ray spectrum is well-represented by a thin thermal plasma model with enhanced metal abundances. The spatial and spectral properties imply that G355.6-0.0 is a member of the mixed-morphology SNRs. The N-H value of similar to 6 x 10(22) cm(-2) supports that G355.6-0.0 is a distant SNR. Suzaku J173530-3236 exhibits a hard X-ray spectrum with a strong Fe emission line, similar to those of cataclysmic variables. The N-H value of similar to 3 x 10(22) cm(-2) is smaller than that of G355.6-0.0, and hence Suzaku J173530-3236 is located at the near side of G355.6-0.0., Oct. 2013, 65, 5, 99 (7 pages), Scientific journal, 10.1093/pasj/65.5.99

Refereed, PUBLICATIONS OF THE ASTRONOMICAL SOCIETY OF JAPAN, OXFORD UNIV PRESS, Evidence for Recombining Plasma in the Supernova Remnant G346.6-0.2, Shigeo Yamauchi; Masayoshi Nobukawa; Katsuji Koyama; Manami Yonemori, We present Suzaku results of the supernova remnant (SNR) G346.6-0.2. The X-ray emission has a center-filled morphology with a size of 6' x 8' within the radio shell. Neither an ionization equilibrium nor non-equilibrium (ionizing) plasma can reproduce the spectra remaining shoulder-like residuals in the 2-4 keV band. These structures are possibly due to a recombination of free electrons to the K-shell of He-like Si and S. The X-ray spectra were well-fitted with a plasma model in a recombination-dominant phase. We propose that the plasma was in a nearly full ionized state at a high temperature of similar to 5 keV, and then the plasma changed to a recombining phase due to selective cooling of electrons to a lower temperature of similar to 0.3 keV. G346.6-0.2 would be in an epoch of the recombining phase., Feb. 2013, 65, 1, 6 (7 pages), Scientific journal, 10.1093/pasj/65.1.6

Refereed, PUBLICATIONS OF THE ASTRONOMICAL SOCIETY OF JAPAN, OXFORD UNIV PRESS, A New Candidate of an X-Ray Luminous Cluster of Galaxies behind the Galactic Plane, Shigeo Yamauchi; Aya Bamba; Katsuji Koyama, We present Suzaku results of an X-ray source, AX J185905+0333, discovered in the ASCA galactic plane survey. The radial profile of AX J185905+0333 is larger than that of the point-spread function. No intensity variation was found during the observation. These facts indicate that AX J185905+0333 is an extended source. A large low-energy absorption, equivalent to N-H of (8-10) x 10(22)cm(-2), was found, which supports that AX J185905+0333 is an extragalactic object behind the galactic plane. The X-ray spectrum exhibits a clear emission line at 4.82 keV, and is represented by a thin-thermal plasma model of 6.6 keV temperature with a redshift of 0.391. Then, the X-ray luminosity was calculated to be 2.7 x 10(45) erg s(-1). These results strongly support that AX J185905+0333 is an X-ray luminous cluster of galaxies behind the galactic plane., Nov. 2011, 63, S957, S961, Scientific journal, 10.1093/pasj/63.sp3.S957

Refereed, PUBLICATIONS OF THE ASTRONOMICAL SOCIETY OF JAPAN, OXFORD UNIV PRESS, Suzaku Observation of the Anomalous X-Ray Pulsar 1E 1841-045, Mikio Morii; Shunji Ktamoto; Noriaki Shibazaki; Nobuyuki Kawai; Makoto Arimoto; Masaru Ueno; Takayoshi Kohmura; Yukikatsu Terada; Shigeo Yamauchi; Hiromitsu Takahashi, We report on the results of a Suzaku observation of the anomalous X-ray pulsar (AXP) IE 1841-045 at the center of the supernova remnant Kes 73. We confirmed that the energy-dependent spectral models obtained by previous separate observations were also satisfied over a wide energy range from 0.4 to similar to 70 keV, simultaneously. Here, the models below similar to 10 keV were a combination of blackbody (BB) and power-law (PL) functions, or of two BBs with different temperatures at 0.6-7.0 keV (Morii et al. 2003. PASJ, 55, L45), and that above similar to 20 keV was a PL function (Kuiper et al. 2004, ApJ, 613, 1173). The combination BB + PL + PL was found to best represent the phase-averaged spectrum. Phase-resolved spectroscopy indicated the existence of two emission regions, one with a thermal and the other with a non-thermal nature. The combination BB + BB + PL was also found to represent the phase-averaged spectrum well. However, we found that this model is physically unacceptable due to an excessively large area of the emission region of the blackbody. Nonetheless, we found that the temperatures and radii of the two blackbody components showed moderate correlations in the phase-resolved spectra. The fact that the same correlations have been observed between the phase-averaged spectra of various magnetars (Nakagawa et al. 2009, PASJ, 61, 109) suggests that a self-similar function can approximate the intrinsic energy spectra of magnetars below similar to 10 keV., Oct. 2010, 62, 5, 1249, 1259, Scientific journal, 10.1093/pasj/62.5.1249

Refereed, PUBLICATIONS OF THE ASTRONOMICAL SOCIETY OF JAPAN, OXFORD UNIV PRESS, A New Candidate of a Cluster of Galaxies, 2XMM J045637.2+522411, Shigeo Yamauchi; Masaru Ueno; Aya Bamba; Katsuji Koyama, We present XMM-Newton and Suzaku results of an X-ray source, 2XMM J045637.2+522411, found during an observation of a galactic supernova remnant (SNR), G156.2+5.7. By comparing its radial profile with the point-spread function, we found that 2XMM J045637.2+522411 is an extended source. X-ray spectra exhibited a line-like structure at 5.7-5.8 keV. Since no abundant element emits an X-ray line at 5-6 keV in the rest-frame, and the most intense emission line in the 5-7 keV energy band is a Fe-K line, the line is likely to be a redshifted Fe-K line. The overall spectra can be represented by a thin-thermal plasma model with a temperature of 3-4 keV and a redshift of 0.15-0.17. No intensity variation was found in the light curve. The observational results indicate that 2XMM J045637.2+522411 is likely to be a cluster of galaxies., Apr. 2010, 62, 2, 219, 224, Scientific journal, 10.1093/pasj/62.2.219

Refereed, ASTROPHYSICAL JOURNAL LETTERS, IOP PUBLISHING LTD, DOPPLER-BROADENED IRON X-RAY LINES FROM TYCHO'S SUPERNOVA REMNANT, Akihiro Furuzawa; Daisuke Ueno; Asami Hayato; Midori Ozawa; Toru Tamagawa; Aya Bamba; John P. Hughes; Hideyo Kunieda; Kazuo Makishima; Stephen S. Holt; Una Hwang; Kenzo Kinugasa; Robert Petre; Keisuke Tamura; Hiroshi Tsunemi; Shigeo Yamauchi, We use Suzaku observations to measure the spatial variation of the Fe K alpha line with radius in the Tycho supernova remnant. The Fe line widths show a significant decrease from a FWHM value of 210 eV at the center to 130 eV at the rim. Over the same radial range the line center energy remains nearly constant. These observations are consistent with a scenario in which the shell of Fe-emitting ejecta in Tycho is expanding at speeds of 2800-3350 km s(-1). The minimum line width we measure is still a factor of two larger than expected from a single component plasma emission model. If thermal Doppler broadening is the dominant additional source of broadening, we infer an ion temperature of (1-3) x 10(10) K., Mar. 2009, 693, 2, L61, L65, Scientific journal, 10.1088/0004-637X/693/2/L61

Refereed, PUBLICATIONS OF THE ASTRONOMICAL SOCIETY OF JAPAN, OXFORD UNIV PRESS, A New Supernova Remnant Candidate and an Associated Outflow in the Sagittarius C Region, Takeshi Go Tsuru; Masayoshi Nobukawa; Hiroshi Nakajima; Hironori Matsumoto; Katsuji Koyama; Shigeo Yamauchi, We present the Suzaku results on a new candidate of a supernova remnant (SNR) in the Sagittarius C region. We detected diffuse X-rays of an elliptical shape (G359.41-0.12) and a chimney-like structure (the Chimney), both of which were fitted with a thin thermal the model of k(B)T similar to 1 keV temperature. The absorption columns are same between these two structures, indicating that both are located at the same distance in the same line of sight. The narrow band image and one-dimensional profile of S xv K alpha at 2.45 keV show that the Chimney is emanating from G359.41-0.12. Therefore, these two sources are physically connected with each other. The sum of the thermal energies of the Chimney and G359.41-0.12 is estimated to be 1.4 x 10(50) erg, typical for a galactic SNR. G359.41-0.12 is likely to be a new SNR candidate and the Chimney is an associated outflow., Jan. 2009, 61, S219, S223, Scientific journal, 10.1093/pasj/61.sp1.S219

Refereed, PUBLICATIONS OF THE ASTRONOMICAL SOCIETY OF JAPAN, OXFORD UNIV PRESS, Iron Emission Lines on the Galactic Ridge Observed with Suzaku, Shigeo Yamauchi; Ken Ebisawa; Yasuo Tanaka; Katsuji Koyama; Hironori Matsumoto; Noriko Y. Yamasaki; Hiromitsu Takahashi; Yuichiro Ezo, In order to elucidate the origin of galactic ridge X-ray emission, we analyzed Suzaku data taken at various regions along the galactic plane, and studied their Fe-K emission line features. Suzaku resolved the Fe line complex into three narrow lines at similar to 6.4 keV, similar to 6.7 keV and similar to 6.97 keV, which are K-lines from neutral (or low-ionized), He-like, and H-like iron respectively. The 6.7 keV line is clearly seen in all of the observed regions, and its longitudinal distribution is consistent with that determined from previous observations. The 6.4 keV emission line was also found in various galactic plane regions (b similar to 0 degrees). Differences in the flux ratios of the 6.4 keV/6.7 keV and 6.97 keV/6.7 keV lines between the galactic plane and the galactic center regions were studied and its implication was discussed., Jan. 2009, 61, S225, S232, Scientific journal, 10.1093/pasj/61.sp1.S225

Refereed, PUBLICATIONS OF THE ASTRONOMICAL SOCIETY OF JAPAN, OXFORD UNIV PRESS, X-Ray Reflection Nebulae with Large Equivalent Widths of the Neutral Iron K alpha Line in the Sagittarius C Region, Hiroshi Nakajima; Takeshi Go Tsuru; Masayoshi Nobukawa; Hironori Matsumoto; Katsuji Koyama; Hiroshi Murakami; Atsushi Senda, This paper reports on the first results of a Suzaku observation in the Sgr C region. We detected four diffuse clumps with strong line emission at 6.4 keV, K alpha from neutral or low-ionized Fe. One of them, M 359.38-0.00, was newly discovered with Suzaku. The X-ray spectra of the two bright clumps, M 359.43-0.07 and M 359.47-0.15, after subtracting the galactic center diffuse X-ray emission (GCDX), exhibit a strong K alpha line from Fe I with large equivalent widths (EWs) of 2.0-2.2 keV and a clear K beta of Fe I. The GCDX in the Sgr C region is composed of the 6.4 keV- and 6.7 keV-associated components. These were phenomenologically decomposed by taking relations between the EWs of the 6.4 keV and 6.7 keV lines. Then, the former EWs against the associated continuum in bright clump regions were estimated to be 2.4(-0.7)(+2.3) keV. Since the two different approaches give similar large EWs of 2 keV, we strongly suggest that the 6.4 keV clumps in the Sgr C region are due to X-ray reflection/fluorescence (the X-ray reflection nebulae)., Jan. 2009, 61, S233, S240, Scientific journal, 10.1093/pasj/61.sp1.S233

Refereed, PUBLICATIONS OF THE ASTRONOMICAL SOCIETY OF JAPAN, OXFORD UNIV PRESS, X-Ray Emission from Supernova Remnants Observed in the ASCA Galactic Plane Survey, Shigeo Yamauchi; Masaru Ueno; Katsuji Koyama; Aya Bamba, X-ray images and spectra of 5 cataloged supernova remnants (SNRs: G12.0-0.1, G346.6-0.2, G348.5+0.1, G348.7+0.3, and G355.6-0.0) observed in the ASCA galactic plane survey are presented. The sizes of X-ray emission from G12.0-0.1, G348.5+0.1, G348.7+0.3, and G355.6-0.0 are comparable to their radio structures, while that of G346.6-0.2 is smaller. The X-ray spectra of all the SNRs were heavily absorbed by interstellar matter with N-H > 10(22) cm(-2). The spectrum of G355.6-0.0 exhibited emission lines, indicating that the X-ray emission has a thin thermal plasma origin, and was well represented by a two-temprature thin thermal emission model. On the other hand, no clear emission-line features were found in the spectre. of the others, and the spectra could be represented by either a thin thermal emission model or a power-law model, Oct. 2008, 60, 5, 1143, 1150, Scientific journal, 10.1093/pasj/60.5.1143

Refereed, PUBLICATIONS OF THE ASTRONOMICAL SOCIETY OF JAPAN, OXFORD UNIV PRESS, Suzaku detection of an intense X-ray flare from an A-type star, HD 161084, Junichiro Miura; Masahiro Tsujimoto; Yohko Tsuboi; Yoshitomo Maeda; Yasuharu Sugawara; Katsuji Koyama; Shigeo Yamauchi, We report on a serendipitous detection of an intense X-ray flare from the Tycho reference source on HD 161084 during a Suzaku observation of the galactic center region for similar to 20 ks. The X-ray Imaging Spectrometer recorded a flare from this A1-type dwarf or subgiant star with a flux of similar to 1.4 x 10(-12) erg s(-1) cm(-2) (0.5-10 keV) and a decay time scale of similar to 0.5 hr. The spectrum is hard with a prominent Fe XXV K alpha emission line at 6.7 keV, which is explained by a similar to 5 keV thin-thermal plasma model attenuated by a similar to 1.4 x 10(21) cm(-2) extinction. The low extinction, which is consistent with the optical reddening, indicates that the source is a foreground star toward the galactic center region. Based on a spectroscopic parallax distance of similar to 530 pc, the peak X-ray luminosity amounts to similar to 1 x 10(32) erg s(-1) (0.5-10 keV). This is much larger than the X-ray luminosity of ordinary late-type main-sequence stars, and the X-ray emission is unattributable to a hidden late-type companion that comprises a wide binary system with the A star. We discuss possible nature of HD 161084, and suggest that it is most likely an interacting binary with elevated magnetic activity in the companion, such as the Algol-type system. The flux detected by Suzaku during the burst is similar to 100-times larger than the quiescent level measured using the archived XMM-Newton and Chandra data. The large flux amplification makes this star a unique example among sources of this class., Feb. 2008, 60, S49, S56, Scientific journal, 10.1093/pasj/60.sp1.S49

Refereed, PUBLICATIONS OF THE ASTRONOMICAL SOCIETY OF JAPAN, OXFORD UNIV PRESS, Suzaku spectroscopy of an X-ray reflection nebula and a new supernova remnant candidate in the Sgr B1 region, Masayoshi Nobukawa; Takeshi Go Tsuru; Yojiro Takikawa; Yoshiaki Hyodo; Tatsuya Inui; Hiroshi Nakajima; Hironori Matsumoto; Katsuji Koyama; Hiroshi Murakami; Shigeo Yamauchi, We made a 100 ks observation of the Sagittarius (Sgr) B1 region at (l, b) = (0.degrees 5, -0.degrees 1) near to the Galactic center (GC) with the Suzaku/XIS. Emission lines of S xv, Fe I, Fe XXV, and Fe XXVI were clearly detected in the spectrum. We found that the Fe XXV and Fe XXVI line emissions smoothly distribute over the Sgr B1 and B2 regions connecting from the GC. This result suggests that the GC hot plasma extends at least up to the Sgr B region with constant temperature. There are two diffuse X-ray sources in the observed region. One of the two (G0.42-0.04) is newly discovered, and exhibits a strong S xv K alpha emission line, suggesting a candidate for a supernova remnant located in the GC region. The other one (M 0.51-0.10), having a prominent Fe I Ka emission line and a strongly absorbed continuum, is likely to be an X-ray reflection nebula. There is no near source bright enough to irradiate M 0.51-0.10. However, the Fe I Ka emission can be explained if Sgr A* was similar to 10(6) times brighter 300 years ago, the light travel time for 100 pc to M 0.51-0.10, than it is at present., Feb. 2008, 60, S191, S199, Scientific journal, 10.1093/pasj/60.sp1.S191

Refereed, PUBLICATIONS OF THE ASTRONOMICAL SOCIETY OF JAPAN, OXFORD UNIV PRESS, Suzaku detection of extended/diffuse hard X-ray emission from the galactic center, Takayuki Yuasa; Ken-Ichi Tamura; Kazuhiro Nakazawa; Motohide Kokubun; Kazuo Makishima; Aya Bamba; Yoshitomo Maeda; Tadayuki Takahashi; Ken Ebisawa; Atsushi Senda; Yoshiaki Hyd; Takeshi Go Tsuru; Katsuji Koyama; Shigeo Yamauchi; Hiromitsu Takahashi, Five on-plane regions within +/-0.degrees 8 of the galactic center were observed with the Hard X-ray Detector (HXD) and the X-ray Imaging Spectrometer (XIS) aboard Suzaku. From all regions, significant hard X-ray emission was detected with HXD-PIN up to 40 keV, in addition to the extended plasma emission which is dominant in the XIS band. The hard X-ray signals are inferred to come primarily from a spatially extended source, rather than from a small number of bright discrete objects. Contributions to the HXD data from catalogued X-ray sources, typically brighter than 1 mCrab, were estimated and removed using information from Suzaku and other satellites. Even after this removal, the hard X-ray signals remained significant, exhibiting a typical 12-40keV surface brightness of 4 x 10(-10) erg cm(-2) s(-1) deg(-2) and power-law-like spectra with a photon index of 1.8. Combined fittings to the XIS and HXD-PIN spectra confirm that a separate hard tail component is superposed onto the hot thermal emission, confirming a previous report based on the XIS data. Over the 5-40 keV band, the hard tail is spectrally approximated by a power law of photon index similar to 2, but better by those with somewhat convex shapes. Possible origins of the extended hard X-ray emission are discussed., Feb. 2008, 60, S207, S221, Scientific journal, 10.1093/pasj/60.sp1.S207

Refereed, PUBLICATIONS OF THE ASTRONOMICAL SOCIETY OF JAPAN, OXFORD UNIV PRESS, Spectral study of the galactic ridge X-ray emission with Suzaku, Ken Ebisawa; Shigeo Yamauchi; Yasuo Tanaka; Katsuji Koyama; Yuichiro Ezoe; Aya Bamba; Motohide Kokubun; Yoshiaki Hyodo; Masahiro Tsujimoto; Hiromitsu Takahashi, In order to carry out a precise spectral study of the Galactic Ridge X-ray Emission using Suzaku, we have observed a typical Galactic plane field at (l, b) = (28 degrees 46, -0 degrees 20), which is already deeply observed with Chandra, and known to be devoid of bright X-ray point sources. Thanks to the low background and high spectral resolution of Suzaku, we were able to resolve three narrow iron K-emission lines from low-ionized (6.41 keV), helium-like (6.67 keV), and hydrogenic ions (7.00 keV). The cosmic-ray ion charge-exchange model or the non-equilibrium ionization plasma model are unlikely to explain these line features, since they require either broad emission lines or lines at intermediate ionization states. Collisional ionization equilibrium plasma is the likely origin for the 6.67 keV and 7.00 keV lines; however, the origin of the 6.41 keV line, which is due to fluorescence from cold material, has not been elucidated. We could also precisely measure the absolute X-ray surface brightness in the direction of the Galactic plane. Excluding point sources brighter than similar to 2 X 10(-13) erg s(-1) cm(-2) (2-10keV), the total surface brightness on the Galactic plane is similar to 6.1 x 10(-11) erg s(-1) cm(-2) deg(-2) (2-10keV), including the contribution of the cosmic X-ray background, which is estimated to be similar to 1.3 x 10(-11) erg s(-1) cm(-2) deg(-2)., Feb. 2008, 60, S223, S229, Scientific journal, 10.1093/pasj/60.sp1.S223

Refereed, PUBLICATIONS OF THE ASTRONOMICAL SOCIETY OF JAPAN, OXFORD UNIV PRESS, A bright transient X-ray source near the galactic center found in archival Ginga data from 1987, Shigeo Yamauchi; Yoshio Nakagawa; Keisuke Sudoh; Shunji Kitamoto, A bright transient X-ray source was detected in the direction of the galactic center with Ginga in 1987 March. A sky position was determined from both data obtained with the All Sky Monitor (ASM) and cross-scan data obtained with the Large Area proportional Counters (LAC). Based on the sky position derived from both the ASM and the LAC data, this source was designated as GS 1741-288. At the beginning of the Ginga observations, GS 1741-288 was in the active state: its energy flux in the 2-10 keV energy band was similar to 10(-8) erg s(-1) cm(-2). The ASM light curve showed that the intensity gradually decayed with an e-folding time of 190 +/- 9d. No remarkable feature, such as periodic or quasi-periodic oscillations was found. The spectral and temporal properties suggest that GS 1741-288 is likely to be a low-mass X-ray binary system containing a weakly magnetized neutron star. Possible identification of the source is also discussed., Dec. 2007, 59, 6, 1141, 1151, Scientific journal, 10.1093/pasj/59.6.1141

Refereed, PUBLICATIONS OF THE ASTRONOMICAL SOCIETY OF JAPAN, OXFORD UNIV PRESS, The X-ray observatory Suzaku, Kazuhisa Mitsuda; Mark Bautz; Hajime Inoue; Richard L. Kelley; Katsuji Koyama; Hideyo Kunieda; Kazuo Makshima; Yoshiaki Ogawara; Robert Petre; Tadayuki Takahashi; Hiroshi Tsunemi; Nicholas E. White; Naohisa Anabuki; Lorella Angelini; Keith Arnaud; Hisamitsu Awaki; Aya Bamba; Kevin Boyce; Gregory V. Brown; Kai-Wing Chan; Jean Cottam; Tadayasu Dotanli; John Doty; Ken Ebisawa; Yuichiro Ezoe; Andrew C. Fabian; Enectali Figueroa; Ryuichi Fujimoto; Yasushi Fukazawa; Tae Furusho; Akihiro Furuzawa; Keith Gendreau; Richard E. Griffiths; Yoshito Haba; Kenji Hamaguchi; Ilana Harrus; Gunther Hasinger; Isamu Hatsukade; Kiyoshi Hayashida; Patrick J. Henry; Junko S. Hiraga; Stephen S. Holt; Ann Hornschemeier; John P. Hughes; Una Hwang; Manabu Ishida; Yoshitaka Ishisaki; Naoki Isobe; Masayuki Itoh; Naoko Iyomoto; Steven M. Kahn; Tuneyoshi Kamae; Hideaki Katagiri; Jun Kataoka; Haruyoshi Katayama; Nobuyuki Kawai; Caroline Kilbourne; Kenzo Kinugasa; Steve Kissel; Shunji Kitamoto; Mitsuhiro Kohama; Takayoshi Kohmura; Motohide Kokubun; Taro Kotani; Jun'ichi Kotoku; Aya Kubota; Greg M. Madejski; Yoshitomo Maeda; Fumiyoshi Makino; Alex Markowitz; Chiho Matsumoto; Hironori Matsumoto; Masaru Matsuoka; Kyoko Matsushita; Dan McCammon; Tatehiko Mihara; Kazutami Misaki; Emi Miyata; Tsunefumi Mizuno; Koji Mori; Hideyuki Mori; Mikio Morii; Harvey Moseley; Koji Mukai; Hiroshi Murakami; Toshio Murakami; Richard Mushotzky; Fumiaki Nagase; Masaaki Namiki; Hitoshi Negoro; Kazubiro Nakazawa; John A. Nousek; Takashi Okajima; Yasushi Ogasaka; Takaya Ohashi; Tai Oshima; Naomi Ota; Masanobu Ozaki; Hideki Ozawa; Arvind N. Parmar; William D. Pence; F. Scott Porter; James N. Reeves; George R. Ricker; Ikuya Sakurai; Wilton T. Sanders; Atsushi Senda; Peter Serlemitsos; Ryo Shibata; Yang Soong; Randall Smith; Motoko Suzuki; Andrew E. Szymkowiak; Hiromitsu Takahashi; Torn Tamagawa; Keisuke Tamura; Takayuki Tamura; Yasuo Tanaka; Makoto Tashiro; Yuzuru Tawara; Yukikatsu Terada; Yuichi Terashima; Hiroshi Tomida; Ken'ichi Torii; Yohko Tsuboi; Masahiro Tsujimoto; Takeshi Go Tsuru; Martin J. L. Turner; Yoshihiro Ueda; Shiro Ueno; Masaru Ueno; Shin'ichiro Uno; Yuji Urata; Shin Watanabe; Norimasa Yamamoto; Kazutaka Yamaoka; Noriko Y. Yamasaki; Koujun Yamashita; Makoto Yamauchi; Shigeo Yamauchi; Tahir Yaqoob; Daisuke Yonetoku; Atsumasa Yoshida, High-sensitivity wide-band X-ray spectroscopy is the key feature of the Suzaku X-ray observatory, launched on 2005 July 10. This paper summarizes the spacecraft, in-orbit performance, operations, and data processing that are related to observations. The scientific instruments, the high-throughput X-ray telescopes, X-ray CCD cameras, non-imaging hard X-ray detector are also described., Jan. 2007, 59, S1, S7, Scientific journal, 10.1093/pasj/59.sp1.S1

Refereed, PUBLICATIONS OF THE ASTRONOMICAL SOCIETY OF JAPAN, OXFORD UNIV PRESS, Suzaku observations of HESS J1616-508: Evidence for a dark particle accelerator, Hironori Matsumoto; Masaru Ueno; Aya Bamba; Yoshiaki Hyodo; Hideyuki Mori; Hideki Uchiyama; Takeshi Go Tsuru; Katsuji Koyama; Jun Kataoka; Hideaki Katagiri; Tadayuki Takahashi; Junko Hiraga; Shigeo Yamauchi; John P. Hughes; Atsushi Senda; Motohide Kokubun; Takayoshi Kohmura; Frederick S. Porter, We observed the bright unidentified TeV gamma-ray source HESS J1616-508 with the X-ray Imaging Spectrometers onboard the Suzaku satellite. No X-ray counterpart was found to a limiting flux of 3.1 x 10(-13) erg s(-1) cm(-2) in the 2-10 keV band, which is some 60-times below the gamma-ray flux in the 1-10 TeV band. This object is bright in TeV gamma-rays, but very dim in the X-ray band, and thus is one of the best examples in the Galaxy of a "dark particle accelerator." We also detected soft thermal emission with kT similar to 0.3-0.6 keV near the location of HESS J1616-508. This may be due to a dust-grain scattering halo from the nearby bright supernova remnant RCW 103., Jan. 2007, 59, S199, S208, Scientific journal, 10.1093/pasj/59.sp1.S199

Refereed, PUBLICATIONS OF THE ASTRONOMICAL SOCIETY OF JAPAN, OXFORD UNIV PRESS, Discovery of a possible X-ray counterpart to HESS J1804-216, Aya Bamba; Katsuji Koyama; Junko S. Hiraga; John P. Hughes; Takayoshi Kohmura; Motohide Kokubun; Yoshitomo Maeda; Hironori Matsumoto; Atsushi Senda; Tadayuki Takahashi; Yohko Tsuboi; Shigeo Yamauchi; Takayuki Yuasa, Suzaku deep observations have discovered two highly significant nonthermal X-ray sources, Suzaku J1804-2142 (Src 1) and Suzaku J1804-2140 (Src 2), positionally coincident with the unidentified TeV gamma-ray source, HESS J1804-216. The X-ray sources are not time variable and show no Counterpart in other wavebands, except for the TeV source. Src 1 is unresolved at Suzaku spatial resolution, whereas Src 2 is extended or composed of multiple sources. The X-ray spectra are highly absorbed, hard, and featureless, and are well fitted by absorbed power-law models with best-fit photon indices and absorption columns of -0.3(-0.5)(+0.5) and 0.2(-0.2)(+2.0) x 10(22) cm(-2) for Src 1, and 1.7(-1.0)(+1.4) and 1.1(-0.6)(+1.0) x 10(23) cm(-2) for Src 2. The measured X-ray absorption to the latter source is signif icantly larger than the total Galactic neutral hydrogen column in that direction. The unabsorbed 2-10 keV band luminosities are 7.5 x 10(32) (d/5 kpc)(2) erg s(-1) (Src 1) and 1.3 x 10(33) (d/5 kpc)(2) erg s(-1) (Src 2), where d is the source distance. Among the handful of TeV sources with known X-ray counterparts, HESS J1804-216 has the largest ratio of TeV gamma-ray to hard X-ray fluxes. We discuss the nature of the emission and propose the Suzaku sources as plausible counterparts to the TeV source, although further observations are necessary to confirm this., Jan. 2007, 59, S209, S214, Scientific journal, 10.1093/pasj/59.sp1.S209

Refereed, PUBLICATIONS OF THE ASTRONOMICAL SOCIETY OF JAPAN, OXFORD UNIV PRESS, Discovery of a new X-ray transient source in the Scutum region with Suzaku, Shigeo Yamauchi; Ken Ebisawa; Aya Bamba; Manabu Ishida; Kazushi Iwasawa; Yasuo Tanaka; Motohide Kokubun; Katsuji Koyama; Hiromitsu Takahashi; Yohko Tsuboi, During an observation of the Galactic plane in the Scutum region with the Suzaku satellite, we discovered a new X-ray transient source, designated Suzaku J1844-0404. Compared with previous Chandra observations of the same field, four Chandra X-ray sources exist within the current positional uncertainty of Suzaku J1844-0404. A firm identification is not possible. From the beginning of the observation, the X-ray intensity was significant at similar to 5 x 10(-14) erg s(-1) cm(-2) (2-10 keV), which may be a possible precursor. Later, the source exhibited a flare with a peak flux of similar to 10(-12) erg s(-1) cm(-2) (2-10 keV). A strong and narrow emission line at similar to 6.66 keV was observed during the flare, most likely the He-like Fe line. The spectrum in 1-10 keV is consistent with a heavily absorbed (N-H similar to 3 x 10(22) H cm(-2)) thin thermal emission with kT as high as similar to 7 keV. A single short flare, as observed, is rather unlikely for a cataclysmic variable. The source is probably an active binary star or a young stellar object., Jan. 2007, 59, S215, S220, Scientific journal, 10.1093/pasj/59.sp1.S215

Refereed, PUBLICATIONS OF THE ASTRONOMICAL SOCIETY OF JAPAN, OXFORD UNIV PRESS, Discoveries of diffuse iron line sources from the Sgr B region, Katsuji Koyama; Tatsuya Inui; Yoshiaki Hyodo; Hironori Matsumoto; Takeshi Go Tsuru; Yoshitomo Maeda; Hiroshi Murakami; Shigeo Yamauchi; Steven E. Kissel; Kai-Wing Chan; Yang Soong, The radio complex Sgr B region was observed with the X-ray Imaging Spectrometer (XIS) on board Suzaku. This region exhibits diffuse iron lines at 6.4, 6.7, and 6.9 keV, which are K alpha lines of Fe I (neutral iron), Fe XXV (He-like iron), and Fe XXVI (H-like iron), respectively. The high energy resolving power of the XIS provided separate maps of the K-shell transition lines from Fe 1 (6.4 keV) and Fe XXV (6.7 keV). Although the 6.7 keV line is smoothly distributed over the Sgr B region, a local excess is found near (l, b) = (0.degrees 61, 0.degrees 01), possibly due to a new SNR. The plasma temperature is kT similar to 3 keV and the age is estimated to be younger than 7 x 10(3) yr. The 6.4 keV image is clumpy with local excesses near Sgr B2 and at (l, b) = (0.degrees 74, -0.degrees 09). Like Sgr B2, this excess may be another candidate of an X-ray reflection nebula., Jan. 2007, 59, S221, S227, Scientific journal, 10.1093/pasj/59.sp1.S221

Refereed, PUBLICATIONS OF THE ASTRONOMICAL SOCIETY OF JAPAN, OXFORD UNIV PRESS, Iron and nickel line diagnostics for the Galactic Center diffuse emission, Katsuji Koyama; Yoshiaki Hyodo; Tatsuya Inui; Hiroshi Nakajima; Hironori Matsumoto; Takeshi Go Tsuru; Tadayuki Takahashi; Yoshitomo Maeda; Noriko Y. Yamazaki; Hiroshi Murakami; Shigeo Yamauchi; Yohko Tsuboi; Atsushi Senda; Jun Kataoka; Hiromitsu Takahashi; Stephen S. Holt; Gregory V. Brown, We have observed the diffuse X-ray emission from the Galactic Center (GC) using the X-ray Imaging Spectrometer (XIS) on Suzaku. The high-energy resolution and the low-background orbit provided excellent spectra of the GC diffuse X-rays (GCDX). The XIS found many emission lines in the GCDX near the energy of K-shell transitions of iron and nickel. The most pronounced features are Fe I K alpha at 6.4 keV and K-shell absorption edge at 7.1 keV, which are from neutral and/or low ionization states of iron, and the K-shell lines at 6.7 keV and 6.9 keV from He-like (Fe XXV K alpha) and hydrogenic (Fe XXVI Ly alpha) ions of iron. In addition, K alpha lines from neutral or low ionization nickel (Ni I K alpha) and He-like nickel (Ni XXVII K alpha), Fe I K beta, Fe XXV K beta, Fe XXVI Ly beta, Fe XXV K gamma, and Fe XXVI Ly gamma were detected for the first time. The line center energies and widths of Fe XXV K alpha and Fe XXVI Ly alpha favor a collisional excitation plasma for the origin of the GCDX. The electron temperature determined from the line flux ratio of Fe XXV K alpha/Fe XXV K beta is similar to the ionization temperature determined from that of Fe XXV K alpha/Fe XXVI Ly alpha. Thus it would appear that the GCDX plasma is close to ionization equilibrium. The 6.7 keV flux and temperature distribution to the galactic longitude is smooth and monotonic, in contrast to the integrated point source flux distribution. These facts support the hypothesis that the GCDX is truly diffuse emission rather than the integration of the outputs of a large number of unresolved point sources. In addition, our results demonstrate that the chemical composition of Fe in the interstellar gas near the GC is constrained to be about 3.5 times solar abundance., Jan. 2007, 59, S245, S255, Scientific journal, 10.1093/pasj/59.sp1.S245

Refereed, ASTROPHYSICAL JOURNAL, IOP PUBLISHING LTD, Chandra deep X-ray observation of a typical galactic plane region and near-infrared identification, K Ebisawa; M Tsujimoto; A Paizis; K Hamaguchi; A Bamba; R Cutri; H Kaneda; Y Maeda; G Sato; A Senda; M Ueno; S Yamauchi; Beckmann, V; TJL Courvoisier; P Dubath; E Nishihara, Using the Chandra Advanced CCD Imaging Spectrometer Imaging array (ACIS-I), we have carried out a deep hard X-ray observation of the Galactic plane region at (l, b) approximate to (28 degrees.5, 0 degrees.0), where no discrete X-ray source had been reported previously. We have detected 274 new point X-ray sources ( 4 sigma confidence), as well as strong Galactic diffuse emission within two partially overlapping ACIS-I fields (similar to 250 arcmin(2) in total). The point-source sensitivity was similar to 3 x 10(-15) ergs s(-1) cm(-2) in the hard X-ray band (2-10 keV) and similar to 2 x 10(-16) ergs s(-1) cm(-2) in the soft band (0.5-2 keV). The sum of all the detected point-source fluxes accounts for only similar to 10% of the total X- ray flux in the field of view. Even hypothesizing a new population of much dimmer and numerous Galactic point sources, the total observed X- ray flux cannot be explained. Therefore, we conclude that X- ray emission from the Galactic plane has a truly diffuse origin. Removing point sources brighter than similar to 3 x 10(-15) ergs s(-1) cm(-2) (2-10 keV), we have determined the Galactic diffuse X-ray flux to be 6.5 x 10(-11) ergs s(-1) cm(-2) deg(-2) (2-10 keV). Only 26 point sources were detected in both the soft and hard bands, indicating that there are two distinct classes of X- ray sources distinguished by their spectral hardness ratios. The surface number density of the hard sources is only slightly higher than that measured at the high Galactic latitude regions, indicating that the majority of the hard sources are background AGNs. Following up the Chandra observation, we have performed a near-infrared (NIR) survey with SofI at ESO/NTT. Almost all the soft X- ray sources have been identified in the NIR, and their spectral types are consistent with main-sequence stars, suggesting that most of them are nearby X- ray-active stars. On the other hand, only 22% of the hard sources had NIR counterparts, which are presumably Galactic. From X- ray and NIR spectral study, they are most likely to be quiescent cataclysmic variables. Our observation suggests a population of greater than or similar to 10(4) cataclysmic variables in the entire Galactic plane fainter than similar to 2 x 10(33) ergs s(-1). We have carried out a precise spectral study of the Galactic diffuse X- ray emission excluding the point sources. Confirming previous results, we have detected prominent emission lines from highly ionized heavy elements in the diffuse emission. In particular, the central energy of the iron emission line was determined to be 6.52(-0.14)(+0.08) keV ( 90% confidence), which is significantly lower than what is expected from a plasma in thermal equilibrium. The downward shift of the iron line center energy suggests nonequilibrium ionization states of the plasma or the presence of a nonthermal process to produce 6.4 keV fluorescent lines., Dec. 2005, 635, 1, 214, 242, Scientific journal

Refereed, PUBLICATIONS OF THE ASTRONOMICAL SOCIETY OF JAPAN, OXFORD UNIV PRESS, X-ray emission from a supernova remnant, G344.7-0.1, observed in the ASCA Galactic Plane Survey, S Yamauchi; M Ueno; K Koyama; A Bamba, X-ray emission from a cataloged radio supernova remnant (SNR), G344.7-0.1, was observed in the ASCA Galactic Plane Survey. The X-ray image showed extended emission with a diameter of 6'-8'. The X-ray spectrum exhibited emission lines from He-like Si, S, Ar, and Ca, which indicates that the X-rays have a thermal plasma origin. The spectrum was represented by a thin thermal plasma model with a temperature of 0.7-0.8 keV. The model fit showed that S and Ca are overabundant relative to the solar values. In addition to the emission lines from highly ionized atoms. an emission line at an energy of similar to 6.4keV was found. This line is attributable to a K transition line from low-ionized iron. The strong Fe-K alpha line may suggest the existence of an Fe-rich plasma., Jun. 2005, 57, 3, 459, 463, Scientific journal, 10.1093/pasj/57.3.459

Refereed, ASTROPHYSICAL JOURNAL, IOP PUBLISHING LTD, X-ray study of Herbig Ae/Be stars, K Hamaguchi; S Yamauchi; K Koyama, We present ASCA results of intermediate- masspre-main-sequence (PMS) stars, or Herbig Ae/Be (HAeBe) stars. Among the 35 ASCA pointed sources, we detect 11 plausible X-ray counterparts. X-ray luminosities of the detected sources in the 0.5-10 keV band are in the range of log L-X similar to30-32 ergs s(-1), which is systematically higher than those of low-mass PMS stars. This fact suggests that the contribution of a possible low-mass companion is not large. Most of the bright sources show significant time variation; in particular, two HAeBe stars MWC 297 and TY CrA-exhibit flarelike events with long decay timescales (e-folding time similar to10-60 ks). These flare shapes are similar to those of low-mass PMS stars. The X-ray spectra are successfully reproduced by an absorbed one- or two-temperature thin-thermal plasma model. The temperatures are in the range of kT similar to1 5 keV, significantly higher than those of main-sequence OB stars (kT < 1 keV). These X-ray properties are not explained by wind-driven shocks, but are more likely due to magnetic activity. On the other hand, the plasma temperature rises as absorption column density increases or as HAeBe stars ascend to earlier phases. The X-ray luminosity reduces after stellar age of a few times 10(6) yr. X-ray activity may be related to stellar evolution. The age of the activity decay is apparently near the termination of jet or outflow activity. We thus hypothesize that magnetic activity originates from the interaction of the large-scale magnetic fields coupled to the circumstellar disk. We also discuss differences in X-ray properties between HAeBe stars and main-sequence OB stars., Jan. 2005, 618, 1, 360, 384

Refereed, Publications of the Astronomical Society of Japan, Oxford University Press, An ultrasoft transient X-ray source in the norma region discovered with ginga, Shigeo Yamauchi, A new X-ray source was discovered in the Norma region with Ginga in 1988 April. The source position, derived from one-dimensional scan data, and its spectral properties are presented. The X-ray emission was dominant below ∼ 6keV and not found in other observations. Thus, it is thought to be an ultrasoft transient X-ray source. The X-ray spectrum, constructed by a scan fit technique, was well represented by either blackbody, thermal bremsstrahlung, power-law, or multicolor disk models. Although all of the spectral models were acceptable from a statistical point of view, the ultrasoft nature of the spectrum and the transient behavior suggest that this source is a candidate source of black hole binaries. © 2005. Astronomical Society of Japan., 2005, 57, 3, 465, 469, 10.1093/pasj/57.3.465

Refereed, PUBLICATIONS OF THE ASTRONOMICAL SOCIETY OF JAPAN, OXFORD UNIV PRESS, XMM-Newton observations of G32.45+0.1 and G38.55+0.0: Diffuse hard X-ray sources found by the ASCA Galactic Plane Survey, H Yamaguchi; M Ueno; K Koyama; A Bamba, We report oil XMM-Newton observations of G32.45 + 0.1 and G38.55 + 0.0. These were discovered as diffuse hard X-ray sources by the ASCA Galactic Plane Survey. but the limited spatial resolution of ASCA could not conclude whether these are truly diffuse or a group of unresolved point-sources. XMM-Newton. with higher spatial resolution than ASCA, confirmed that G32.45 + 0.1 has a diffuse shell-like structure with a radius of similar to 4'. The spectrum shows a featureless continuum, and can thus be fitted by a power-law model of Gamma similar to 2.2 with an absorption of N-H similar to 5.2 x 10(22) cm(-2). From this N-H value, we estimated the distance to G32.45+0.1 to be similar to 17kpc. Thus, the luminosity (in the 0.5- 10.0 keV band) and radius of the shell are similar to 9.5 x 10(34) ergs s(-1) and similar to 20 pc, respectively. The radio complex sources in the NRAO/VLA Sky Survey (NVSS; 1.4 GHz) are globally associated with the X-ray shell of G32.45 + 0. 1. Therefore, G32.45 + 0.1 is likely to be a synchrotron-dominant shell-like SNR. No significant diffuse structure was found in the XMM-Newton image of another ASCA diffuse source, G38.55 + 0.0. The upper limit of the observed flux (0.5- 10.0 keV) is estimated to be 9.0 x 10(-13) ergs cm(-2) s(-1), which is consistent with the ASCA result., Dec. 2004, 56, 6, 1059, 1065, Scientific journal, 10.1093/pasj/56.6.1059

Refereed, PUBLICATIONS OF THE ASTRONOMICAL SOCIETY OF JAPAN, OXFORD UNIV PRESS, An ultrasoft transient X-ray source near the Galactic bulge region, S Yamauchi; E Nakamura, Further analysis of an ultrasoft transient X-ray source near the Galactic bulge region is reported. This source was discovered in scanning observations with Ginga, and was at first designated as GS 1734-275 (Makino 1988). The source position was re-determined using revised satellite attitude data, and then this source was named GS 1732-273. The revised position is in agreement with those of the transient sources, KS 1732-273, discovered with Mir-Kvant in 1989, and 1RXS J173602.0-272541, discovered with the ROSAT all-sky survey in 1990. The X-ray spectrum, constructed by a scan-fit technique, is well represented by a multicolor disk model with a temperature at the inner disk radius of 0.7-0.8 keV. The spectral properties and the transient behavior suggest that GS 1732-273 is a candidate source of black hole binaries., Oct. 2004, 56, 5, 803, 808, Scientific journal, 10.1093/pasj/56.5.803

Refereed, ASTROPHYSICAL JOURNAL, UNIV CHICAGO PRESS, Diffuse hard X-ray sources discovered with the ASCA Galactic plane survey, A Bamba; M Ueno; K Koyama; S Yamauchi, We found diffuse hard X-ray sources G11.0+0.0, G25.5+0.0, and G26.6-0.1 in the ASCA Galactic plane survey data. The X-ray spectra are featureless with no emission line and are fitted with both models of a thin thermal plasma in nonequilibrium ionization and a power-law function. The source distances are estimated to be 1-8 kpc, using the best-fit N-H values under the assumption that the mean density in the line of sight is 1 H cm(-3). The source sizes and luminosities are then 4.5-27 pc and (0.8-23) x 10(33) ergs s(-1). Although the source sizes are typical for supernova remnants (SNR) with young-to-intermediate ages, the X-ray luminosity, plasma temperature, and weak emission lines in the spectra are all unusual. This suggests that these objects are either shell-like SNRs dominated by X-ray synchrotron emission, like SN 1006 or, alternatively, plerionic SNRs. The total number of these classes of SNRs in our Galaxy is also estimated., May 2003, 589, 1, 253, 260, Scientific journal

Refereed, ASTRONOMISCHE NACHRICHTEN, WILEY-V C H VERLAG GMBH, Galactic X-ray surveys, K Ebisawa; S Yamauchi; A Bamba; M Ueno; A Senda, We review highlights of the results obtained from recent Galactic X-ray survey observations, in particular ASCA Galactic center and plane surveys and our Chandra deep survey on the (l, b) approximate to (28.degrees5, 0.degrees0) region. Strong hard X-ray diffuse components are observed from Galactic ridge, center and bulge. and they have both thermal and non-thermal spectral components. Dozens of discrete and extended sources have been discovered on the Galactic plane, which also indicate thermal and/or non-thermal X-ray energy spectra, They are often associated with radio sources and are considered to be SNR candidates. Most of the hard X-ray point sources in the outer part of the Galactic plane are considered to be background AGNs, while fraction of the Galactic hard X-ray sources (such as quiescent dwarf novae) increases toward the Galactic center. Most of the soft X-ray sources on the Galactic plane are presumably nearby active stars., 2003, 324, 1-2, 52, 56, Scientific journal, 10.1002/asna.200310014

Refereed, ASTRONOMISCHE NACHRICHTEN, WILEY-V C H VERLAG GMBH, Search for synchrotron X-ray dominated SNRs in the ASCA galactic plane survey, A Bamba; M Ueno; K Koyama; S Yamauchi; K Ebisawa, 2003, 324, 1-2, 139, 139, Scientific journal, 10.1002/asna.200310038

Refereed, ASTRONOMISCHE NACHRICHTEN, WILEY-V C H VERLAG GMBH, Near-infrared identification of the dimmest X-ray sources on the Galactic plane with the ESO/NTT SOFI camera, K Ebisawa; Beckmann, V; TJL Courvoisier; P Dubath; H Kaneda; Y Maeda; S Yamauchi; E Nishihara, 2003, 324, 1-2, 158, 158, Scientific journal, 10.1002/asna.200310057

Refereed, ASTROPHYSICAL JOURNAL SUPPLEMENT SERIES, IOP PUBLISHING LTD, ASCA X-ray source catalog in the galactic center region, M Sakano; K Koyama; H Murakami; Y Maeda; S Yamauchi, The ASCA satellite made 107 pointing observations on a 5 x 5 deg(2) region around the center of our Galaxy from 1993 to 1999. In the X-ray images of the 0.7-3 keV or 3-10 keV bands, we found 52 point sources and a dozen diffuse sources. All the point sources are uniformly fitted with an absorbed power-law model. For selected bright sources, Sgr A*, AX J1745.6-2901, A1742-294, SLX 1744-300, GRO J1744-28, SLX 1737-282, GRS 1734-292, AX J1749.2-2725, KS 1741-293, GRS 1741.9-2853, and an unusual flare source XTE J1739-302, we present further detailed spectral and timing analyses and discuss their nature. The dozen extended X-ray sources comprise radio supernova remnants, giant molecular clouds, and some new discoveries. Most show emission lines from either highly ionized atoms or low-ionized irons. The X-ray spectra were fitted with either a thin thermal or power-law model. This paper summarizes the results and provides the ASCA X-ray source catalog in the Galactic center region., Jan. 2002, 138, 1, 19, 34, Scientific journal

Refereed, PUBLICATIONS OF THE ASTRONOMICAL SOCIETY OF JAPAN, OXFORD UNIV PRESS, Discovery of a transient X-ray pulsar, AX J1841.0-0536, in the Scutum arm region with ASCA, A Bamba; J Yokogawa; M Ueno; K Koyama; S Yamauchi, We report on the discovery of a transient X-ray pulsar, AX J1841.0-0536, serendipitously found in the Scutum arm region with the ASCA in two separate observations. The X-ray flux is very faint at the beginning, but exhibits two flares in the second observation. The flare flux increases by a factor 10 within only similar to I hr. Coherent pulsations with a period of 4.7394 +/- 0.0008 s were detected in the brightest flare phase. The X-ray spectra in the quiescent and flare phases were fitted with an absorbed power-law model with a photon index similar to I plus a narrow Gaussian line at the center energy of 6.4 keV. The interstellar column density of similar to 3 X 10(22)cm(-2) may indicate that AX J1841.0-0536 is located at a tangential point of the Scutum arm at similar to 10kpc distance. The coherent pulsations, large flux variability, and the spectral shape suggest that AX J1841.0-0536 is a Be/X-ray binary pulsar., Dec. 2001, 53, 6, 1179, 1183, Scientific journal, 10.1093/pasj/53.6.1179

Refereed, PUBLICATIONS OF THE ASTRONOMICAL SOCIETY OF JAPAN, OXFORD UNIV PRESS, A diffuse X-ray source, AX J1843.8-0352: Association with the radio complex G28.6-0.1 and identification of a new supernova remnant, A Bamba; M Ueno; K Koyama; S Yamauchi, ASCA discovered an extended source in the constellation Scutum. The X-ray morphology is an elliptical shape elongated from north to south with a mean diameter of about 10 '. The image center is located at RA(2000) = 18(h)43(m)53(s), DEC2000 = -03 degrees 52 ' 55 " (hereafter, AX J1843.8- 0352). The north and south rims of AX J1843.8-0352 are associated with non-thermal radio sources C and F of the G28.6-0.1 complex (Helfand et al. 1989. AAA 49.125.029). The X-ray spectrum was fitted with a model of either a thin thermal plasma in non-equilibrium ionization of a temperature 5.4 keV or a power-law of photon index 2.1. The absorption column is (2.4-4.0) x 10(22)cm(-2), which probably places this source in the Scutum arm. With a reasonable distance assumption of about 7 kpc. we estimate the mean diameter and X-ray luminosity to be similar to 20 pc and similar to 3 x 10(34) erg s(-1), respectively. Although a Sedov solution for a thin thermal plasma model gives parameters of a young shell-like SNR, no strong emission lines are found with the metal abundances being similar to solar. Thus, a more likely scenario for both the radio and X-ray spectra and the morphologies is that AX J1843.8-0352 is a shell-like SNR which predominantly emits synchrotron X-rays., Aug. 2001, 53, 4, L21, L24, Scientific journal, 10.1093/pasj/53.4.L21

Refereed, SCIENCE, AMER ASSOC ADVANCEMENT SCIENCE, Origin of the hard X-ray emission from the galactic plane, K Ebisawa; Y Maeda; H Kaneda; S Yamauchi, The Galactic plane is a strong emitter of hard x-rays (2 to 10 kiloelectron volts), and the emission forms a narrow continuous ridge. The currently known hard x-ray sources are far too few to explain the ridge x-ray emission, and the fundamental question of whether the ridge emission is ultimately resolved into numerous dimmer discrete sources or truly diffuse emission has not yet been settled. In order to obtain a decisive answer, using the Chandra X-ray Observatory, we carried out the deepest hard x-ray survey of a Galactic plane region that is devoid of known x-ray point sources. We detected at least 36 new hard x-ray point sources in addition to strong diffuse emission within a 17' by 17' field of view. The surface density of the point sources is comparable to that at high Galactic latitudes after the effects of Galactic absorption are considered. Therefore, most of these point sources are probably extragalactic, presumably active galaxies seen through the Galactic disk. The Galactic ridge hard x-ray emission is diffuse, which indicates omnipresence within the Galactic plane of a hot plasma, the energy density of which is more than one order of magnitude higher than any other substance in the interstellar space., Aug. 2001, 293, 5535, 1633, 1635, Scientific journal

Refereed, ASTROPHYSICAL JOURNAL SUPPLEMENT SERIES, IOP PUBLISHING LTD, Faint X-ray sources resolved in the ASCA Galactic plane survey and their contribution to the Galactic ridge X-ray emission, M Sugizaki; K Mitsuda; H Kaneda; K Matsuzaki; S Yamauchi; K Koyama, The X-ray emission from the central region of the Galactic plane, \l\ less than or similar to 45 degrees and \b\ less than or similar to 0.degrees4, was studied in the 0.7-10 keV energy band with a spatial resolution of similar to3' with the Advanced Satellite for Cosmology and Astrophysics (ASCA) observatory. We developed a new analysis method for the ASCA data to resolve discrete sources from the extended Galactic ridge X-ray emission (GRXE). We successfully resolved 163 discrete sources with an X-ray flux down to 10(-12.5) ergs cm(-2) s(-1) and determined the intensity variations of the GRXE as a function of the Galactic longitude with a spatial resolution of about 1 degrees. The longitudinal intensity variation in the energy band above 4 keV, for which there is little absorption in the Galactic plane, shows a large enhanced feature within \l\ less than or similar to 30 degrees. This suggests a strong enhancement ment of X-ray emissivity of the GRXE inside the 4 kpc arm of the Galaxy. Searches for identifications of the resolved X-ray sources with cataloged X-ray sources and optical stars show that the 66% are unidentified. Spectral analysis of each source shows that a large number of the unidentified sources have hard X-ray spectra obscured by the Galactic interstellar medium. We classified the sources into several groups by the flux, the hardness and the softness of the spectra, and performed further detailed analysis for the spectra summed within each group. Possible candidates of X-ray origins of these unidentified sources are discussed based on the grouping spectral analysis. Also, we derived the log N-log S relations of the resolved sources in the energy bands below and above 2 keV separately. The log N-log S relation of the Galactic X-ray sources above 2 keV was obtained for the first time with this study. It is represented by a power-law with an index of -0.79 +/- 0.07 after correction for the contribution of extragalactic X-ray sources. This flat power-law relation suggests that the spatial distribution of the X-ray sources should have an armlike structure in which the solar system is included. The integrated surface brightness of the resolved sources is about 10% of the total GRXE in both energy bands. The approximately 90% of the emission remaining is still unresolved., May 2001, 134, 1, 77, 102, Scientific journal

Refereed, NEW CENTURY OF X-RAY ASTRONOMY, ASTRONOMICAL SOC PACIFIC, ASCA observations of two molecular cloud cores in the Perseus molecular cloud complex, S Yamauchi; Y Tsuboi; K Koyama, We report ASCA observations of two molecular cloud cores in the Perseus molecular cloud complex, Barnard I and the core containing a Class 0 protostar, IRAS 03282+3035. We detected 4 X-ray sources and found counterparts for two of them. We found no X-ray emission from young IRAS sources, IRAS 03282+3035 and IRAS 03301+3057, and obtained upper limits of their X-ray emissions., 2001, 251, 286, 287, International conference proceedings

Refereed, PUBLICATIONS OF THE ASTRONOMICAL SOCIETY OF JAPAN, OXFORD UNIV PRESS, ASCA X-ray observations of the NGC 2023 and NGC 2024 regions, S Yamauchi; R Kamimura; K Koyama, This paper presents the properties of X-ray sources in the regions of NGC 2023 and NGC 2024 observed with ASCA. We found 14 point-like sources in the NGC 2023 field. In the NGC 2024 field, on the other hand, we found extended X-ray emission in the central, dust lane of NGC 2024, and resolved 5 pointlike sources around the nebula. From the positional coincidence and moderate column density of N-H similar to 1.6 x 10(22) H cm(-2), the extended source is mostly attributable to an integrated emission from X-ray emitting young stellar objects (YSOs) found with ROSAT. However, the plasma temperature of similar to 4 keV is higher than the ROSAT results as well as those of usual YSOs. Possible counterparts have been found for the other resolved sources, except two; one has large absorption at low energies and the other has moderate absorption. The plasma temperatures and luminosities from the point sources, except for an O-type star zeta Ori and a star exhibiting X-ray flares, are estimated to be similar to 1-5 keV and 10(30.6)-10(31.5) erg s(-1) in the 0.5-10.0 keV energy band (assuming the distance of 400 pc), respectively. We found no X-ray peak at the position of a Class 0 protostar, NGC 2023-MM1., Dec. 2000, 52, 6, 1087, 1096, Scientific journal, 10.1093/pasj/52.6.1087

Refereed, PUBLICATIONS OF THE ASTRONOMICAL SOCIETY OF JAPAN, OXFORD UNIV PRESS, Discovery of a slow X-ray pulsator, AX J1740.1-2847, in the galactic center region, M Sakano; K Torii; K Koyama; Y Maeda; S Yamauchi, We report the discovery of an X-ray pulsar: AX J1740.1-2847, from the Galactic center region. This source was found as a faint hard X-ray object on 1998 September 7-8 with the ASCA Galactic center survey observation. Then, coherent pulsations of P = 729 +/- 14 s period were detected. The X-ray spectrum is described by a flat power-law of similar to 0.7 photon index. The large absorption column of log N-H similar to 22.4 cm(-2) indicates that AX J1740.1-2847 is a distant source, larger than 2.4 kpc, and possibly near to the Galactic center region. The luminosity in the 2-10 keV band is larger than 2.5x10(33) erg s(-1), or likely to be 3.2 x 10(34) erg s(-1) at the Galactic-center distance. Although the slow-pulse period does not discriminate whether AX J1740.1-2847 is a white dwarf or neutron-star binary, the flat power-law and moderate luminosity strongly favor a neutron-star binary., Dec. 2000, 52, 6, 1141, 1145, Scientific journal, 10.1093/pasj/52.6.1141

Refereed, PUBLICATIONS OF THE ASTRONOMICAL SOCIETY OF JAPAN, OXFORD UNIV PRESS, ASCA observations of the NGC 2264 molecular cloud, M Nakano; S Yamauchi; K Sugitani; K Ogura, We have made ASCA observations of the molecular cloud associated with NGC 2264, and detected nine and five sources in the soft and hard X-ray band images, respectively. Most of them are identified with known pre-main-sequence stars or protostellar objects. Two Class I sources with intermediate luminosities and one Class II source associated with molecular outflow are promising candidates for X-ray emitters. An optically thin hot-plasma model with two components can reproduce the GIS X-ray spectra, including both of the Class I sources. The hard X-rays probably arise from these Class I sources, and are intrinsically very luminous, > 10(32) erg s(-1) in the 0.7-10.0 keV energy band, and their luminosities lie between low-mass Class I sources and that of the W 3 massive core region. Since near-infrared survey data reveal that Class I sources are surrounded by embedded young clusters, the soft X-ray components could be explained by aggregates of low-mass pre-main-sequence stars., Jun. 2000, 52, 3, 437, 446, Scientific journal, 10.1093/pasj/52.3.437

Refereed, ASTROPHYSICAL JOURNAL, UNIV CHICAGO PRESS, Discovery of a new pulsating X-ray source with a 1549.1 second period, AX J183220-0840, M Sugizaki; K Kinugasa; K Matsuzaki; Y Terada; S Yamauchi; J Yokogawa, A new pulsating X-ray source, AX J183220-0840, with a 1549.1 s period was discovered at R.A. = 18(h)32(m)20(s) and decl, = -8 degrees 40'30 " (J2000, with an uncertainty of 0'.6) during an ASCA observation on the Galactic plane. The source was observed two times, in 1997 and in 1999. A phase-averaged X-ray flux of 1.1 x 10(-11) ergs cm(-2) s(-1) and a pulsation period of 1549.1 +/- 0.4 s were consistently obtained from these two observations. The X-ray spectrum was represented by a flat, absorbed power law with a photon index of Gamma similar or equal to 0.8 and an absorption column density of N-H similar or equal to 1.3 x 10(22) cm(-2). Also, a signature of iron K-shell line emission with a centroid of 6.7 keV and an equivalent width of approximately 450 eV was detected. From the pulsation period and the iron-line feature, AX J183220-0840 is likely to be a magnetic white dwarf binary with a complexly absorbed thermal spectrum with a temperature of about 10 keV., May 2000, 534, 2, L181, L184, Scientific journal

Refereed, PUBLICATIONS OF THE ASTRONOMICAL SOCIETY OF JAPAN, OXFORD UNIV PRESS, X-ray flares from an H alpha emission-line star in the Orion Region, Kiso A0904-105, S Yamauchi; R Kamimura; K Koyama, We analyzed ASCA data, including the reflection nebula NGC 2023, and discovered two X-ray flares from an Her emission-line star, Kiso A0904-105, located at similar to 30' to the southwest of NGC 2023. The separation time between the two flares was similar to 4 hr. The temperatures of the first and second flares reached (5-7) x 10(7) K and the luminosities around the flare peaks were similar to 10(33) erg s(-1) (0.5-10.0 keV energy band, assuming the distance of 400 pc), which are comparable to those of the giant X-ray flares from T Tauri stars. After the flare peaks, X-ray intensity exhibited art exponential decay. Comparing the flares with those from T Tauri stars, we found that the physical parameters in the flaring plasma were within the range of those obtained from T Tauri stars., Feb. 2000, 52, 1, 161, 166, Scientific journal, 10.1093/pasj/52.1.161

Refereed, BROAD BAND X-RAY SPECTRA OF COSMIC SOURCES, PERGAMON PRESS LTD, ASCA observations of the supernova remnant G156.2+5.7, S Yamauchi; J Yokogawa; H Tomida; K Koyama; K Tamura, We report on the X-ray spectra in the wide energy band from the north rim and the central regions of the supernova remnant G156.2+5.7 obtained with ASCA. No clear shell structure is found: the surface brightness in the north rim is nearly the same as that in the center. The spectra from the north rim and the central regions are composed, at least, of 2 components: one is a thin thermal component with a temperature of about 0.4 keV and the other is a hard component represented by either a thin thermal emission model with a temperature higher than a few keV or a power-law model with a photon index of similar to 2. Si and S abundances in the central region are found to be 3-10 times larger than those in the north rim region. Results of simultaneous fits of the ASCA and the Ginga spectra are also presented. (C) 2000 COSPAR. Published by Elsevier Science Ltd., 2000, 25, 3-4, 567, 570, Scientific journal

Refereed, BROAD BAND X-RAY SPECTRA OF COSMIC SOURCES, PERGAMON PRESS LTD, X-ray lobes of W50/SS433 system, M Namiki; N Kawai; T Kotanil; S Yamauchi; W Brinkmann, The X-ray lobes lie on both sides (east and west) of SS433, and are presumably produced by the interaction of the jets of SS433 with the surrounding SNR W50. The non-thermal nature of the east lobe has been reported by Yamauchi et al. (1994) using the ASCA data. With the further ASCA observations, we studied the spectra and morphology of both the east and west lobes in detail. Their spectra have no emission lines, and are best described by power-law models with interstellar absorption. The X-ray emission becomes softer on the both sides with the distance from SS433. The surface brightness peaks closer to SS433 in the high-energy band than in the low energy band, suggesting that the high energy electrons in the X-ray lobes lose energies by synchrotron emission as they travel away from SS433. We estimate the magnetic field and the total energy of the high energy electrons to be a few mu G and similar to 10(46) erg respectively, where equipartition in energy beta een the relativistic electrons and magnetic field is assumed. (C) 2000 COSPAR. Published by Elsevier Science Ltd., 2000, 25, 3-4, 709, 712, Scientific journal

Refereed, BROAD BAND X-RAY SPECTRA OF COSMIC SOURCES, PERGAMON PRESS LTD, ASCA observations of the supernova remnant G156.2+5.7, S Yamauchi; J Yokogawa; H Tomida; K Koyama; K Tamura, We report on the X-ray spectra in the wide energy band from the north rim and the central regions of the supernova remnant G156.2+5.7 obtained with ASCA. No clear shell structure is found: the surface brightness in the north rim is nearly the same as that in the center. The spectra from the north rim and the central regions are composed, at least, of 2 components: one is a thin thermal component with a temperature of about 0.4 keV and the other is a hard component represented by either a thin thermal emission model with a temperature higher than a few keV or a power-law model with a photon index of similar to 2. Si and S abundances in the central region are found to be 3-10 times larger than those in the north rim region. Results of simultaneous fits of the ASCA and the Ginga spectra are also presented. (C) 2000 COSPAR. Published by Elsevier Science Ltd., 2000, 25, 3-4, 567, 570, Scientific journal

Refereed, BROAD BAND X-RAY SPECTRA OF COSMIC SOURCES, PERGAMON PRESS LTD, X-ray detection from shell-like SNR G359.1-0.5, J Yokogawa; M Sakano; K Koyama; S Yamauchi, We detected X-rays from the shell-like radio SNR (supernova remnant) G359.1-0.5 with ASCA satellite. Center-filled X-rays with no pulsation are found, but no X-ray from the radio shell is detected. The X-ray spectrum shows (1) a large absorption of 8x10(22) H cm(-2), suggesting that G359.1-0.5 lies near the Galactic center, which is consistent with radio observations and (2) two prominent lines whose center energies correspond to the emission lines from He-like Si and H-like S. The line profile could be reproduced with a two-component plasma model, suggesting presence of a high temperature plasma together with an overabundance of S. No difference between emitting regions of the two components is found. (C) 2000 COSPAR. Published by Elsevier Science Ltd., 2000, 25, 3-4, 571, 574, Scientific journal

Refereed, BROAD BAND X-RAY SPECTRA OF COSMIC SOURCES, PERGAMON PRESS LTD, Non thermal X-ray from galactic supernova remnants, H Tomida; K Koyama; J Yokogawa; S Yamauchi, We present the ASCA results of three galactic supernova remnants, G156.2+5.7,G347.5-0.5, and G315.4-2.3. The spectra all exhibit the hard component without the thermal feature, and are spatially extended. We propose that these X-rays come from the extremely high energy electrons accelerated by the Fermi process. (C) 2000 COSPAR. Published by Elsevier Science Ltd., 2000, 25, 3-4, 695, 698, Scientific journal

Refereed, BROAD BAND X-RAY SPECTRA OF COSMIC SOURCES, PERGAMON PRESS LTD, X-ray lobes of W50/SS433 system, M Namiki; N Kawai; T Kotanil; S Yamauchi; W Brinkmann, The X-ray lobes lie on both sides (east and west) of SS433, and are presumably produced by the interaction of the jets of SS433 with the surrounding SNR W50. The non-thermal nature of the east lobe has been reported by Yamauchi et al. (1994) using the ASCA data. With the further ASCA observations, we studied the spectra and morphology of both the east and west lobes in detail. Their spectra have no emission lines, and are best described by power-law models with interstellar absorption. The X-ray emission becomes softer on the both sides with the distance from SS433. The surface brightness peaks closer to SS433 in the high-energy band than in the low energy band, suggesting that the high energy electrons in the X-ray lobes lose energies by synchrotron emission as they travel away from SS433. We estimate the magnetic field and the total energy of the high energy electrons to be a few mu G and similar to 10(46) erg respectively, where equipartition in energy beta een the relativistic electrons and magnetic field is assumed. (C) 2000 COSPAR. Published by Elsevier Science Ltd., 2000, 25, 3-4, 709, 712, Scientific journal

Refereed, ASTROPHYSICAL JOURNAL, IOP PUBLISHING LTD, Merging young clusters in the Shapley supercluster, H Hanami; T Tsuru; K Shimasaku; S Yamauchi; Y Ikebe; K Koyama, We present the ASCA spectral diagnostics of the X-ray-emitting gas of five clusters of galaxies in the Shapley concentration. X-rays from two rich clusters, A3562 and A3558, nicely follow the standard L-X-k(B) T relation, while the X-ray luminosity of a poor cluster, A3556, comes below the relation line. The X-ray spectrum of another poor cluster, SC 1329-313, is found to be peculiar; the gas temperature is higher than that estimated from the velocity dispersion of its member galaxies. The energy of the iron K alpha line is also higher than that expected from the temperature of the plasma considered in ionization equilibrium and hence is attributable to a plasma in the recombination-dominant phase. We infer that high-temperature gas and highly ionized iron are relies of past major merger events in the formation phase of poor clusters at several times 10(8) yr ago. The putative merger heated the gas to high temperature by the associated shock and produced highly ionized iron as well. The high-temperature gas is gradually cooled down by adiabatic expansion, but the temperature is presently still higher than that expected from the velocity dispersion of galaxies. Iron atoms in the plasma, on the other hand, remain in highly ionized states with irregularities in the temperature distribution. We propose a dynamical sequence of clusters in the Shaply concentration; SC 1329-313 is an ongoing merger, A3556 is a candidate for postmerger, SC 1327-312 is a relaxed poor cluster, while A3562 and A3558 are already developed and rich clusters even with some mergers in succession. The Shapley concentration thus can be called a kindergarten of clusters of galaxies., Aug. 1999, 521, 1, 90, 98, Scientific journal

Refereed, PUBLICATIONS OF THE ASTRONOMICAL SOCIETY OF JAPAN, OXFORD UNIV PRESS, X-ray observations of the Orion OB1b association, M Nakano; S Yamauchi; K Sugitani; K Ogura; T Kogure, We report on the broad-band X-ray images and spectra for the Orion OB1b association obtained with ASCA. More than forty X-ray sources were detected in three fields, and about half of them have likely optical counterparts in the Guide Star Catalog. Their temperature and X-ray luminosities at the assumed distance of 450 pc are 4 keV and 1 x 10(30)-1 x 10(31) erg s(-1) in the total energy band (0.5-10 keV), respectively. In one field covering the Horsehead Nebula and NGC 2023, several X-ray sources were identified with known candidates for low-mass pre-main-sequence stars, including V615 Ori. Among them, four sources are emission-line stars with X-ray emission. Some X-ray sources were also found in the chain of small reflection nebulosities illuminated by OB association members near to epsilon Ori. The X-ray emission from sources having optical counterparts is consistent with thin thermal plasma of temperatures of 1-2 keV. X-ray emission from possible extragalactic sources is also reported., Feb. 1999, 51, 1, 1, 12, Scientific journal, 10.1093/pasj/51.1.1

Refereed, ASTRONOMISCHE NACHRICHTEN, WILEY-V C H VERLAG GMBH, Magnetic activities in Young Stellar Objects, Y Tsuboi; K Hamaguchi; K Koyama; S Yamauchi, With ASCA, we detected hard X-rays from low-mass and high-mass Young Stellar Objects (YSOs), deeply embedded in dense molecular cloud cores. The X-rays from YSOs possessed line emissions from highly ionized ions of heavy elements, and were well fitted with thin-thermal plasma model. Some of them exhibited time valiabilities like solar flares, while their luminosities were at least 3-5 orders of magnitude larger than those from the Sun. These results support a scenario that stars in very young stage always emit magnetic-powered X-rays independently of the mass., 1999, 320, 4-5, 175, 176, Scientific journal

Refereed, ASTRONOMISCHE NACHRICHTEN, WILEY-V C H VERLAG GMBH, X-ray activities in the Galactic Center Region, Y Maeda; K Koyama; K Imanishi; H Murakami; M Nishiuchi; M Sakano; M Tsujimoto; J Yokogawa, With ASCA, we obtained detailed X-ray images and spectra of the Galactic Center. X-rays in the central parsecs from the dynamical center of the Galaxy, Sgr A*, were dominated by extended emission. Since Sgr A* was not spatially resolved from the extended structure, an upper limit to its luminosity was found to be 3 x 10(35) erg s(-1). This result indicates that the current AGN activity of the Galactic nucleus is very low. In the central hundreds of parsecs, X-ray stars, thin thermal diffuse plasma, and iron fluorescent emission from molecular clouds were seen. Based on the analyses of the S-ray stars and both of the diffuse components, we discuss some features which are possibly related to past nuclear activities., 1999, 320, 4-5, 177, 178, Scientific journal

Refereed, ASTRONOMISCHE NACHRICHTEN, WILEY-V C H VERLAG GMBH, Investigation of the galactic ridge X-ray emission, H Kaneda; K Makishima; S Yamauchi; M Sugizaki; NY Yamasaki, 1999, 320, 4-5, 322, 322, Scientific journal

Refereed, ASTRONOMISCHE NACHRICHTEN, WILEY-V C H VERLAG GMBH, The X-ray global view of the Galactic Center region with the ASCA survey, M Sakano; K Koyama; J Yokogawa; H Murakami; M Nishiuchi; Y Maeda; S Yamauchi, We present the preliminary results of the hard X-ray global mapping of the Galactic Center region with ASCA. Many point sources and diffuse structures are resolved more clearly than before in the 2-10 keV band. Iron line emission is also intensely distributed along the Galactic plane. It is interpreted that either high temperature plasma concentrates on the Plane, or the molecular clouds illuminated by external strong X-ray sources are densely distributed along the Plane, or possibly both mechanisms are important., 1999, 320, 4-5, 330, 330, Scientific journal

Refereed, ASTRONOMISCHE NACHRICHTEN, WILEY-V C H VERLAG GMBH, ASCA observations of the Orion B cloud region, S Yamauchi; R Kamimura, 1999, 320, 4-5, 331, 331, Scientific journal

Refereed, ASTRONOMISCHE NACHRICHTEN, WILEY-V C H VERLAG GMBH, Non-thermal emission from the Galactic Supernova Remnants, H Tomida; K Koyama; S Yamauchi, 1999, 320, 4-5, 342, 342, Scientific journal

Refereed, ASTRONOMISCHE NACHRICHTEN, WILEY-V C H VERLAG GMBH, Faint X-ray sources resolved in the ASCA Galactic Plane Survey and their contribution to the X-ray ridge emission, M Sugizaki; K Matsuzaki; H Kaneda; S Yamauchi; K Mitsuda, 1999, 320, 4-5, 383, 383, Scientific journal

Refereed, ASTROPHYSICAL JOURNAL, IOP PUBLISHING LTD, Discovery of a 220 second X-ray pulsar, AX J1749.2-2725, K Torii; K Kinugasa; K Katayama; T Kohmura; H Tsunemi; M Sakano; M Nishiuchi; K Koyama; S Yamauchi, We report here the discovery of a faint 220 s X-ray pulsar, AX J1749.2-2725, with ASCA. In the analysis, we used a method that can detect a pulsating source in a field of view contaminated by stray light. The source was observed on four occasions between 1995 March and 1997 September. The observed source flux was similar to 3.0 x 10(-11) ergs s(-1) cm(-2) (2-10 keV) in 1995 March and became an order of magnitude fainter during the 2.5 yr interval. We cannot rule out the possibility that AX J1749.2 - 2725 is a nearby (d less than or similar to 1.3 kpc) DQ Her-type white dwarf binary, while the hard X-ray spectrum and the transient behavior suggest that it is a distant (d similar to 8.5 kpc) binary system containing a neutron star., Dec. 1998, 508, 2, 854, 858, Scientific journal

Refereed, PUBLICATIONS OF THE ASTRONOMICAL SOCIETY OF JAPAN, OXFORD UNIV PRESS, ASCA observations of the Chamaeleon II dark cloud, S Yamauchi; K Hamaguchi; K Koyama; H Murakami, ASCA results of eight X-ray sources in the Chamaeleon II dark cloud are presented. Six sources were identified as low-mass young stellar objects, either Class II-III sources or T Tauri stars with X-ray temperatures and luminosities in the range of 0.8-3 keV and 10(29.9)-10(31.1) erg s(-1), respectively. Two of them showed time variability: one with typical hare profile and the other with a light curve showing fast-rise and gradual decay. These variable sources exhibited a higher temperature than did those of the other sources with less time variability. We found a high-temperature, time-variable, and moderately absorbed X-ray source which has no cataloged counterpart at any other wavelength. We also found hard X-rays at the position of a Herbig Ae candidate with an extremely large N-H of 2 x 10(23) H cm(-2), one order of magnitude higher than that estimated from the optical extinction. The origin of the X-rays, including these two sources, are discussed., Oct. 1998, 50, 5, 465, 474, Scientific journal, 10.1093/pasj/50.5.465

Refereed, ASTROPHYSICAL JOURNAL, IOP PUBLISHING LTD, Discovery of a 7 second X-ray pulsar, AX J1845.0-0300, K Torii; K Kinugasa; K Katayama; H Tsunemi; S Yamauchi, We report here a serendipitous discovery of a faint X-ray pulsar, AX J1845.0-0300, with ASCA. Its period of similar to 7 s, together with its low luminosity and the soft spectrum, suggest that it may be the eighth candidate member of braking X-ray pulsars. Two observations, 3.5 yr apart, showed a significant flux decrease of more than 1 order of magnitude. The source is in the Scutum arm region (l similar to 30 degrees), which was claimed as a colony of X-ray pulsars by Koyama et al. This discovery strengthens the hypothesis by Koyama et al. that there may be a number of low-luminosity pulsars on the Galactic plane, particularly in the Scutum arm region., Aug. 1998, 503, 2, 843, 847, Scientific journal

Refereed, PUBLICATIONS OF THE ASTRONOMICAL SOCIETY OF JAPAN, OXFORD UNIV PRESS, Discovery of X-ray emission from a radio supernova remnant G352.7-0.1, K Kinugasa; K Torii; H Tsunemi; S Yamauchi; K Koyama; T Dotani, We report on the first detection of X-rays from the radio supernova remnant (SNR) G352.7-0.1 with the ASCA Galactic Plane Survey Project. An X-ray image with a shell-like morphology similar to that of the radio band and a spectrum with prominent K-shell lines from highly ionized Si, S, and Ar are presented. These features provide convincing evidence that the X-rays are due to a shock-heated optically thin hot plasma. The spectra are represented by a non-equilibrium ionization (NEI) model with an electron temperature of kT similar to 2.0 keV, an ionization parameter of tau similar to 10(11.0)cm(-3)s, and an absorption of N-H similar to 2.9 x 10(22)cm(-2). We report on evidence of overabundances of Si and S of similar to 3.7 and similar to 3.4, relative to the solar values, respectively. The large absorption indicates that G352.7-0.1 is near to the galactic center region and, after removing the absorption, the X-ray flux in the 1-10 keV band is estimated to be F-X(1-10 keV) similar to 1.2 x 10(-11) erg cm(-2) s(-1). Assuming the SNR to be in the Sedov phase and near to the galactic center (8.5 kpc), G352.7-0.1 is estimated to have a SN explosion energy and age of E-SN similar to 2 X 10(50) erg and t(age) similar to 2200 yr, respectively; hence, it is a middle-aged SNR., Apr. 1998, 50, 2, 249, 255, Scientific journal, 10.1093/pasj/50.2.249

Refereed, ASTROPHYSICAL JOURNAL, UNIV CHICAGO PRESS, Discovery of the faint X-ray pulsar AX J1820.5-1434 with ASCA, K Kinugasa; K Torii; Y Hashimoto; H Tsunemi; K Hayashida; S Kitamoto; Y Kamata; T Dotani; F Nagase; M Sugizaki; Y Ueda; N Kawai; K Makishima; S Yamauchi, A new X-ray pulsar, AX J1820.5-1434, has been discovered during the ASCA Galactic plane survey project on April 9, at R.A. = 18(h)20(m)29.(s)5, decl. = -14 degrees 34'24 " (equinox 2000.0; error radius 0.'5). A coherent pulsation was detected from the source with an apparent barycentric pulse period of 152.26 +/- 0.04 s. The mean flux, not corrected for the interstellar absorption, was 2.3 x 10(-11) ergs s(-1) cm(-2) in the 2-10 keV energy band. The energy spectra obtained by the GIS and SIS can be fitted by a power-law model (photon index = 0.9 +/- 0.2) with a large column density of 9.8 +/- 1.7 x 10(22) H atoms cm(-2). These parameters indicate that the new pulsar is a highly obscured accretion-driven binary X-ray pulsar. This discovery of a faint pulsar suggests existence of many hidden pulsars in our Galaxy., Mar. 1998, 495, 1, 435, 439, Scientific journal, 10.1086/305291

Refereed, ASTRONOMISCHE NACHRICHTEN, WILEY-V C H VERLAG GMBH, Ginga faint source survey, S Yamauchi; H Awaki; K Iwasawa; Y Kamata; K Koyama; Y Tawara, 1998, 319, 1-2, 92, 92, Scientific journal

Refereed, ASTRONOMISCHE NACHRICHTEN, WILEY-V C H VERLAG GMBH, Study of X-ray SNRs detected in the ASCA Galactic Plane Survey project, S Yamauchi; K Koyama; K Kinugasa; K Torii; M Nishiuchi; T Kosuga; Y Kamata, 1998, 319, 1-2, 111, 111, Scientific journal

Refereed, ASTROPHYSICAL JOURNAL, UNIV CHICAGO PRESS, Complex spectra of the galactic ridge X-rays observed with ASCA, H Kaneda; K Makishima; S Yamauchi; K Koyama; K Matsuzaki; NY Yamasaki, X-ray spectra of the Galactic ridge emission in the Scutum arm region have been obtained with ASCA GIS and SIS in the energy range 0.7-10 keV. The observed spectra are basically of thermal emission from thin hot plasmas, and individual K emission lines from helium-like Mg, Si, S, and Fe ions are confirmed in both the GIS and SIS spectra. This means that the Galactic ridge X-ray emission cannot be explained by a single-temperature ionization-equilibrium plasma model. It cannot, however, be reproduced even if a nonequilibrium ionization model is introduced; thus multiple plasma components are required. The GIS spectra are fairly well fitted by a double-temperature nonequilibrium ionization plasma model with temperatures of kT similar to 0.8 keV and kT similar to 7 keV. The softer component is found to be in an extremely low ionization state, with n(e)t similar to 10(9) cm(-3) s, while the harder component is in a relatively high ionization state, though not yet in a full equilibrium, The GRXE properties obtained with the GIS are carefully reexamined by the highly resolved spectral-line features with the SIS. The soft and hard components are absorbed by equivalent hydrogen columns of 0.7 x 10(22) cm(-2) and 4.6 x 10(22) cm(-2), respectively. The surface brightness of the soft and hard components at b similar to 0 degrees are estimated to be 1.9 x 10(-6) and 5.3 x 10(-7) ergs cm(-2) s(-1) sr(-1) respectively, both in the 0.5-10 keV band. The surface brightness of the softer component extends toward significantly higher (similar to 2 degrees) Galactic latitudes than the harder component, although their actual scale heights may be similar at similar to 100 pc if the differences in their observable depths are taken into account. Spectral properties of the two components are seen to depend on the latitude; the most noticeable effect is a rapid decrease in the Fe K line equivalent width seen in the hard component. Attempts are made to interpret the two components in terms of diffuse hot plasmas filling the interstellar space., Dec. 1997, 491, 2, 638, 652, Scientific journal

Refereed, PUBLICATIONS OF THE ASTRONOMICAL SOCIETY OF JAPAN, OXFORD UNIV PRESS, Discovery of an 11-s X-ray pulsar in the galactic-plane section of the Scorpius constellation, M Sugizaki; F Nagase; K Torii; K Kinugasa; T Asanuma; K Matsuzaki; K Koyama; S Yamauchi, During a galactic-plane survey with ASCA in 1996 September, we detected a relatively bright, soft source at R.A. = 17(h)8(m)46.(s)6, DEC. = -40 degrees 9'27'' (J2000), and discovered an 11-s X-ray pulsation from the source. This source has been identified with the ROSAT source 1RXS J170849.0-400910. From a timing analysis of the source, we obtained a barycentric pulse period of P = 10.99759+/-0.00005 s with a broad sinusoidal shape of a pulse fraction of similar to 30%. The energy spectrum in the 0.8-10 keV region is very soft, and can be fitted by a power-law model with a photon index of 3.5 and an absorption column density of 1.8 x 10(22) cm(-2). The observed pulse-phase-averaged flux in the range 0.8-10 keV is 4.3 x 10(-11) erg cm(-2) s(-1), which corresponds to 1.7 x 10(-10) erg cm(-2) s(-1) after correcting for soft X-ray absorption. During an observation interval of about 14 hr, neither a significant change in the pulsation period, nor a significant variation in the phase-averaged flux was detected. From these X-ray properties, we suggest that this newly discovered X-ray pulsar might be a member of a small subgroup of ''anomalous'' X-ray pulsars with a period close to 6-9 s., Oct. 1997, 49, 5, L25, L30, Scientific journal, 10.1093/pasj/49.5.L25

Refereed, ASTROPHYSICAL JOURNAL, UNIV CHICAGO PRESS, ASCA observations of the Barnard 209 dark cloud and an intense X-ray flare on V773 Tauri, SL Skinner; M Gudel; K Koyama; S Yamauchi, ASCA detected an intense X-ray flare on the weak-lined T Tauri star V773 Tau (=HD 283447) during a 30 ks observation of the Barnard 209 dark cloud in 1995 September. This star is a spectroscopic binary (K2 V + K5 V) and shows signs of strong magnetic surface activity including a spot-modulated optical light curve. The Bare was seen only during its decay phase but is still one of the strongest ever recorded from a T Tauri star with a peak luminosity L-X = 10(32.4) ergs s(-1) (0.5-10 keV), a maximum temperature of at least 42 million K, and energy release greater than or similar to 10(37) ergs. A shorter ASCA observation taken. live months later showed V773 Tau in a quiescent state (L-X = 10(31.0) ergs s(-1)) and detected variable emission from the infrared binary IRAS 04113 + 2758. The differential emission measure (DEM) distribution during the V773 Tau flare shows a bimodal temperature structure that is almost totally dominated by hot plasma at an average temperature of approximate to 37 million K. Using information from time-resolved spectra, we examine the flare decay in terms of solar flare models (cooling loops and two-ribbon Bares) and also consider possible nonsolar behavior (interbinary Bares, star-disk Bares, and rotational X-ray modulation). Solar models are unable to reproduce the unusual convex-shaped X-ray light curve, which decays slowly over a timespan of at least 1 day. However, the light curve decay is accurately modeled as a sinusoid with an inferred X-ray period of 2.97 days, which is nearly identical to the optical rotation period(s) of the two K-type components. This provides tantalizing evidence that the Baring region was undergoing rotational occultation, but periodic X-ray variability is not yet proven since our ASCA observation spans only one-third of a rotation cycle., Sep. 1997, 486, 2, 886, 902, Scientific journal

Refereed, PUBLICATIONS OF THE ASTRONOMICAL SOCIETY OF JAPAN, OXFORD UNIV PRESS, X-ray analysis of the rho Ophiuchi dark cloud with ASCA: Source identification, X-ray spectra, and temporal variability, Y Kamata; K Koyama; Y Tsuboi; S Yamauchi, This paper presents a comprehensive study with the Japanese X-ray astronomical satellite ASCA on X-rays from the main body of the rho Ophiuchi dark cloud. We have constructed separate X-ray images using 3 energy bands and 12 time-sliced data, and thereby detected 19 X-ray sources, doubling the previous ASCA results of II X-ray sources. Three of the sources are associated with class-I infrared sources, which precede the T Tauri phase. Half of the 19 sources were found to be time variable, and 5 flare-like events with an averaged energy of > 3 x 10(35) erg were observed. With the analogy of solar flares, we estimated the flare loop height and plasma density to be 3 x 10(11) cm and 3 x 10(11) cm(-3), respectively. Among these sources, a flare from the class-I source EL 29 exhibited an order-of-magnitude larger absorption (N-H) than in quiescence states, which may indicate the exsistence of a dense protostellar disk., Aug. 1997, 49, 4, 461, 470, Scientific journal, 10.1093/pasj/49.4.461

Refereed, ASTROPHYSICAL JOURNAL, IOP PUBLISHING LTD, Hard X-ray emission from the galactic ridge, NY Yamasaki; T Ohashi; F Takahara; S Yamauchi; K Koyama; T Kamae; H Kaneda; K Makishima; Y Sekimoto; M Hirayama; T Takahashi; T Yamagami; S Gunji; T Tamura; S Miyazaki; M Nomachi, Hard X-ray and gamma-ray emissions from the Galactic ridge were studied with the large area proportional counter (LAC) on the Ginga satellite and a balloon-borne detector Welcome-1. In the scanning observations with the LAC, diffuse hard X-rays were detected along the Galactic plane between l = -20 degrees and l = 40 degrees. The measured spectrum shows that a hard component exists in the Galactic ridge emission above 10 keV, in addition to the hot plasma component. The estimated luminosity of the Galactic ridge emission is around 2 x 10(38) ergs s(-1) in the 3-16 keV band. Welcome-1 observed the gamma-ray ridge emission at around l similar to 345 degrees between 50 and 600 keV. These two results and a recent COMPTEL study suggest that the spectrum of the diffuse Galactic ridge emission extends over the keV-MeV range. From the observed spectral slope, bremsstrahlung by electrons is shown to be the dominant emission mechanism. This implies that low-energy electrons must be supplied continuously to sustain emission in the hard X-ray band. We propose a scenario in which the thermal electrons in the hot plasma responsible for the strong Fe K X-ray emission are shock-accelerated continuously in supernova remnants (SNRs), producing the observed hard X-ray and gamma-ray emissions from the Galactic ridge., Jun. 1997, 481, 2, 821, 831, Scientific journal, 10.1086/304097

Refereed, PUBLICATIONS OF THE ASTRONOMICAL SOCIETY OF JAPAN, OXFORD UNIV PRESS, Discovery of non-thermal X-rays from the northwest shell of the new SNR RX J1713.7-3946: The second SN 1006?, K Koyama; K Kinugasa; K Matsuzaki; M Nishiuchi; M Sugizaki; K Torii; S Yamauchi; B Aschenbach, We report on the ASCA results of a featureless X-ray spectrum from RX J1713.7-3946, a new shell-like SNR discovered with the ROSAT all-sky survey. The northwest part of RX J1713.7-3946 was in the field of the ASCA Galactic Plane Survey Project, and was found to exhibit a shell-like structure. The spectrum, however, shows neither line emission nor any signature of a thermal origin. Instead, a power-law model with a photon index of 2.4-2.5 gives a reasonable fit to the spectrum, suggesting a non-thermal origin. Together with the similarity to SN 1006, we propose that RX J1713.7-3946 is the second example, after SN 1006, of synchrotron X-ray radiation from a shell of SNRs. Since the synchrotron X-rays suggest the existence of extremely high energy charged particles in the SNR shell, our discovery should have a strong impact on the origin of cosmic X-rays., Jun. 1997, 49, 3, L7, L11, Scientific journal, 10.1093/pasj/49.3.L7

Refereed, RADIATION FROM BLACK HOLES, FUTURE MISSIONS TO PRIMITIVE BODIES AND MIDDLE ATMOSPHERIC FINE STRUCTURES, PERGAMON PRESS LTD, ASCA observation of the Galactic Center, S Yamauchi; Y Maeda; K Koyama, X-ray imaging and spectroscopic observations near the Galactic Center in the 0.5-10 keV energy band were carried out with the X-ray satellite ASCA. Several X-ray sources were detected. Luminosities of the sources are estimated to be of order 10(35)-10(36) erg s(-1). The largely extended emission with K-shell transition lines from highly ionized atoms were confirmed. Moreover, an extended emission of the 6.4 keV line from the low ionized iron atom was discovered. The 6.4 keV line intensity is elongated to the north-east from the Galactic Center along the galactic plane and well correlates with the distribution of the dense molecular clouds observed in the radio bands. We interpret that the 6.4 keV line originates from the florescent from the molecular cloud irradiated by bright X-ray source. (C) 1997 COSPAR., 1997, 19, 1, 63, 70, Scientific journal

Refereed, ASTRONOMY & ASTROPHYSICS SUPPLEMENT SERIES, EDITIONS PHYSIQUE, Diffuse hard X-ray emission from the Galactic ridge, NY Yamasaki; T Ohashi; F Takahara; S Yamauchi; T Kamae; H Kaneda; K Makishima; K Koyama, We re-analyze Ginga scanning observation data and present hard X-ray spectra and the distribution along the Galactic ridge. The spectra exhibit a hard component much in excess of single temperature thermal bremsstrahlung with kT = 5 - 10 keV, and the intensity is consistent with a power-law extension from the gamma-ray measurements. This result suggests that there is continuous emission over keV similar to GeV range from an extended region in the Galactic ridge. This implies that freshly accelerated electrons are responsible for the emission., Dec. 1996, 120, 4, C393, C396, Scientific journal

Refereed, ASTROPHYSICAL JOURNAL, IOP PUBLISHING LTD, ASCA observations of HD 104237 (A4e) and the origin of X-ray emission from Herbig Ae stars, SL Skinner; S Yamauchi, ASCA observed the bright Herbig star HD 104237 (A4e) for 30 ks in 1995 April, providing the best X-ray spectrum yet obtained of an intermediate mass pre-main-sequence star. The objective was to identify the physical mechanism responsible for the X-ray emission, with emphasis on discriminating between the softer emission that is characteristic of shocks and the harder emission (greater than or equal to 1 keV) that is normally associated with magnetic activity. Spectral fits using optically thin plasma models show that most of the emission comes from a cool component at 0.2-0.4 keV (similar to 2-4 MK) and a hotter component whose temperature is not tightly constrained but is above 1.6 keV (similar to 18 MK). We consider several possible emission mechanisms, including wind shocks, accretion shocks, a wind-fed magnetosphere, and a corona. Our main conclusion is that the X-ray emission most likely arises in a corona. However, coronal X-ray emission is unanticipated since Herbig stars are thought to lack the convection zones needed to sustain magnetic activity via a solar-like dynamo. We examine two possible solutions to this apparent paradox, namely (1) a corona around the Herbig star itself, sustained by a nonsolar shear-induced dynamo (Tout & Pringle 1995), and (2) a corona around a faint late-type companion whose presence is suspected on the basis of recent infrared observations., Nov. 1996, 471, 2, 987, 1001, Scientific journal

Refereed, PUBLICATIONS OF THE ASTRONOMICAL SOCIETY OF JAPAN, OXFORD UNIV PRESS, Broad-band X-ray observations of the Orion region with ASCA, S Yamauchi; K Koyama; M Sakano; K Okada, Broad-band X-ray images and spectra of the Orion Nebula region were obtained with the X-ray satellite ASCA. Fifty two point-like sources were resolved, including the Orion Trapezium. A large fraction of the optical counterparts of the ASCA sources were classified as G-M type stars. Spectral model fits and count ratios (flux ratio between soft and broad bands) revealed that most of the point sources exhibit a high-temperature plasma of similar to 2-5 keV. Model fits of the X-ray spectra from extended regions around the Orion Nebula (M42), the reflection nebula NGC 1977, and the sky between these nebulae required at least two-temperature components of typically 0.7-1 keV and 3-5 keV. From selected high-flux sources, we also found that the model of a 2-temperature thin thermal plasma is more likely than that of a single-temperature. X-ray light curves from these sources were time variable, but showed no large flares. We thus suggest that the hard X-rays are generated even in relatively quiescent states., Oct. 1996, 48, 5, 719, 737, Scientific journal, 10.1093/pasj/48.5.719

Refereed, PUBLICATIONS OF THE ASTRONOMICAL SOCIETY OF JAPAN, OXFORD UNIV PRESS, A New Eclipsing X-Ray Burster near the Galactic Center: A Quiescent State of the Old Transient A1742-289, Y Maeda; K Koyama; M Sakano; T Takeshima; S Yamauchi, With ASCA, we found highly absorbed X-rays from the position of the bright transient source A1742-289 with a variable flux ranging from 8 x 10(-12) to 4 x 10(-11) erg s(-1) cm(-2) in the 3-10 keV band. We discovered an X-ray burst and eclipses from A1742-289, establishing that A1742-289 is an eclipsing low-mass X-ray binary. Using the black-body radius during an X-ray burst, we estimated the distance of A1742-289 to be about 10 kpc, or near to the galactic center. The burst peak flux was then found below the Eddington limit of a neutron stay. Excess soft X-rays during the eclipse were detected, which are interpreted to be scattering by interstellar dust-grains. Since A1742-289 was found to be an X-ray emitter, even in the quiescent state with a moderate but variable flux, and since A1742-289 is lying only 1'.3 from the galactic center, previously reported X-ray fluxes of the galactic center (Sgr A*) with non-imaging instruments might have suffered due to possible contamination of A1742-289., Jun. 1996, 48, 3, 417, 423, Scientific journal, 10.1093/pasj/48.3.417

Refereed, PUBLICATIONS OF THE ASTRONOMICAL SOCIETY OF JAPAN, OXFORD UNIV PRESS, Unresolved X-ray emission from the galactic ridge with ASCA, S Yamauchi; H Kaneda; K Koyama; K Makishima; K Matsuzaki; T Sonobe; Y Tanaka; N Yamasaki, We report on the ASCA results of hard X-ray imaging and spectroscopic observations of the galactic ridge (the Scutum arm region). The bulk of X-rays in the field of view could not be explained by an integrated emission of resolved sources, indicating that most of the galactic-ridge X-rays are due to a diffuse thin hot plasma. The X-ray luminosity of discrete sources contributing to the galactic-ridge emission was estimated to be less than similar to 2 x 10(33) erg s(-1) in the 2-10 keV energy band. Emission lines from helium-like Si, S, and Fe ions were confirmed in the spectra, which means that the galactic ridge X-ray emission can not be explained by a single temperature ionization equilibrium plasma model. We give some constraints on the origin of the galactic-ridge emission., Apr. 1996, 48, 2, L15, L20, 10.1093/pasj/48.2.L15

Refereed, PUBLICATIONS OF THE ASTRONOMICAL SOCIETY OF JAPAN, OXFORD UNIV PRESS, X-ray observations of NGC 2110 with Ginga and ASCA, I. Hayashi; K. Koyama; H. Awaki; S. Ueno; S. Yamauchi, We present the Ginga and ASCA results for the narrow emission line galaxy NGC 2110. Using Ginga data we found a fast time-variability of a few hours, superimposed on a relatively constant X-ray flux. The X-ray spectrum was well fitted with an absorbed power-law plus iron K emission-line model, in which no significant reflection component was required. Using ASCA data we confirmed the previous detection of extra soft X-ray emission and a K-shell emission line from ''cold'' iron in the simple absorbed power-law spectrum. For the first time we detected a K-shell absorption edge of ''cold'' iron. This edge feature, combined with the Ginga results, indicates that the reflection process is not dominant in NGC 2110. We propose that these iron line and edge features are due to a partial covering material with N-H similar to 10(23) cm(-2), which presumably comprises ''hidden'' broad line region (BLR) clouds., Apr. 1996, 48, 2, 219, 229, Scientific journal, 10.1093/pasj/48.2.219

Refereed, PUBLICATIONS OF THE ASTRONOMICAL SOCIETY OF JAPAN, OXFORD UNIV PRESS, ASCA view of our galactic center: Remains of past activities in X-rays?, K Koyama; Y Maeda; T Sonobe; T Takeshima; Y Tanaka; S Yamauchi, Detailed X-ray images and spectra of the galactic-center region up to 10 keV were obtained with ASCA. Diffuse thermal-emission with distinct K alpha lines from highly ionized ions of various elements has confirmed the presence of an extended high-temperature plasma. The fluorescent X-ray emission from cold iron atoms in molecular clouds was also found, possibly due to irradiation by X-rays from the center, which was bright in the past, but is presently dim. The results suggest that the galactic center exhibited intermittent activities with a time-averaged energy generation rate comparable to Seyfert nuclei, a class of active galactic nuclei., Apr. 1996, 48, 2, 249, 255, Scientific journal, 10.1093/pasj/48.2.249

Refereed, ASTROPHYSICAL JOURNAL SUPPLEMENT SERIES, UNIV CHICAGO PRESS, CALIBRATING THE BROAD-BAND X-RAY TELESCOPE, KA WEAVER; KA ARNAUD; EA BOLDT; D CHRISTIAN; M CORCORAN; SS HOLT; K JAHODA; R KELLEY; FE MARSHALL; RF MUSHOTZKY; R PETRE; G RAWLEY; PJ SERLEMITSOS; EM SCHLEGEL; AP SMALE; JH SWANK; AE SZYMKOWIAK, This paper describes the calibration of the two solid-state Si(Li) X-ray detectors and the X-ray telescopes that flew as part of Goddard Space Flight Center's Broad Band X-Ray Telescope (BBXRT) experiment on board the space shuttle Columbia in 1990 December. During the 9 day shuttle mission, BBXRT performed similar to 150 observations of 82 celestial sources. The content of the archive is summarized here. Although BBXRT had a relatively short life, it stands as a milestone in X-ray astronomy as being the first instrument to offer moderate spectral resolution over a wide bandpass (0.3-12.0 keV). Among other things, this paper discusses the effective area calibration of the instrument, the flux calibration and flux corrections for off-axis observations, the detector background, and optimal background subtraction techniques. The on-axis effective area calibration for the central detector elements was performed using data from the Crab Nebula, while other carefully selected targets were used for calibration of the outer detector elements. The remaining systematic uncertainties in the effective area calibration for point sources observed both on and off axis are generally less than 5%-10%. The energy scale is known to better than 0.5% at 6.0 keV for both detectors. The results presented here have an impact on the calibration of other medium resolution X-ray experiments such as the CCDs on board ASCA (Astro-D) as well as the Advanced X-Ray Astrophysics Facility detectors., Jan. 1995, 96, 1, 303, 324, Scientific journal

Refereed, PUBLICATIONS OF THE ASTRONOMICAL SOCIETY OF JAPAN, ASTRONOMICAL SOC JAPAN, NEW TRANSIENT-X-RAY SOURCE IN THE SCUTUM REGION DISCOVERED WITH ASCA, S YAMAUCHI; T AOKI; K HAYASHIDA; H KANEDA; K KOYAMA; M SUGIZAKI; Y TANAKA; H TOMIDA; Y TSUBOI, Using the ASCA satellite we have discovered a new transient X-ray source at the position of RA(2000)= 18(h)45(m)2(s), Dec(2000) = -4 degrees 33'31'' (uncertainty = 1'), designated as AX 1845.0-0433. The NH-corrected X-ray flux was similar to 3 x 10(-12) erg s(-1) cm(-2) in the 0.7-10 keV region at the beginning of the observation; the X-ray source then suddenly flared up to a level of about 1 x 10(-9) erg s(-1) cm(-2) in the 0.7-10 keV region after N-H-correction within less than a few hours. It exhibited flare-like activity on the minimum time scale of a few ten minutes; the activity lasted until the end of the observation. The X-ray spectra in the quiescent and flare states resemble those of binary X-ray pulsars. However, no coherent pulsation was found in the range from 125 ms to 4096 s., 1995, 47, 2, 189, 194, Scientific journal

Refereed, PUBLICATIONS OF THE ASTRONOMICAL SOCIETY OF JAPAN, ASTRONOMICAL SOC JAPAN, IRON LINE ENERGY AND EQUIVALENT WIDTH OF THE GALACTIC-RIDGE EMISSION, S YAMAUCHI; K KOYAMA, We report on the energy and equivalent width of the iron line as a function of the plasma temperature of the Galactic Ridge emission. The line energies and equivalent widths are systematically lower than those expected from a collisional ionization equilibrium plasma with cosmic abundance. We propose the possibility that the optically thin hot plasma is in a non-equilibrium ionization state with an ionization parameter (nt) of 10(10)-10(11) cm(-3) s, and give some constraints on the physical conditions of the Galactic Ridge plasma., 1995, 47, 4, 439, 443, Scientific journal

Refereed, ASTROPHYSICAL JOURNAL, UNIV CHICAGO PRESS, X-RAY OBSERVATIONS OF CYGNUS A USING THE GINGA SATELLITE, S UENO; K KOYAMA; M NISHIDA; S YAMAUCHI; MJ WARD, X-ray observations of Cypus A with the Ginga satellite require at least two components: (1) a power law with low energy absorption and (2) a thermal bremsstrahlung component with K-shell transition lines from highly ionized iron. The power law probably originates from the active galactic nucleus of Cypus A, as seen through a high column of gas. The photon index and hydrogen-equivalent column density are 1.98(+0.18/-0.20) and 3.75(+0.75/-0.71) X 10(23) H atoms cm-2, respectively. The luminosity corrected for this absorption column is about 10(45) ergs s-1 in the 2-10 keV band, which is within the range typical of ''quasars.'' This evidence strongly supports the idea that an obscured quasar resides at the center of Cygnus A. The thermal component can be attributed to emission from the hot intracluster gas. We have determined the X-ray luminosity and electron temperature of the intracluster gas to be 10(45) ergs s-1 and 7.3 keV, respectively. These X-ray properties are typical of those found for a rich cluster, although the environment suggests a poor cluster., Aug. 1994, 431, 1, L1, L4, Scientific journal

Refereed, MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, BLACKWELL SCIENCE LTD, A HARD X-RAY HALO AROUND CYG X-3, S KAFUKU; S YAMAUCHI; M YAMAUCHI; N KAWAI; M MATSUOKA; K KOYAMA; T KIFUNE, Ginga observations have confirmed the extended hard X-ray component around Cyg X-3 which has been detected by EXOSAT. Scanning observations of Cyg X-3 show that this component extends up to 2-degrees from Cyg X-3 along the Galactic plane. The surface brightness observed by Ginga is consistent with that observed by the EXOSAT ME. The ratio of the count rates in the 3-6 and 6-10 keV bands shows that the extended component has either a thermal bremsstrahlung spectrum with a temperature of 6 +/- 2 keV or a power-law spectrum with a photon index of 2.3 +/- 0.3. If this is associated with. Cyg X-3, the X-ray luminosity in the 2-10 keV band is estimated to be about 1 X 10(36) erg s-1. We discuss two alternative explanations for the origin of the X-ray halo: thermal emission from a hot gas or synchrotron radiation of the ultra-high-energy electrons which are expected to be produced along with ultra-high-energy gamma-rays., May 1994, 268, 2, 437, 443, Scientific journal

Refereed, PUBLICATIONS OF THE ASTRONOMICAL SOCIETY OF JAPAN, ASTRONOMICAL SOC JAPAN, A NONTHERMAL X-RAY-SPECTRUM FROM THE SUPERNOVA REMNANT W-50, S YAMAUCHI; N KAWAI; T AOKI, Hard X-ray properties of the supernova remnant W 50 are presented. The extended lobe structure is confirmed in the 0.7-10 keV energy band. The surface brightness in the 0.7-4 keV band has a clear peak at the region far from SS 433, similar to that obtained by the Einstein Observatory. The shape in the high energy band (4-10 keV) is roughly consistent with that in the low energy band (0.7-4 keV), but shows a flat top structure. The X-ray spectrum from the extended structure shows a non-thermal spectrum without apparent emission lines. The spectrum becomes harder as the distance from SS 433 decreases. We discuss the origin of the X-rays in terms of synchrotron emission., 1994, 46, 3, L109, L113, Scientific journal

Refereed, PUBLICATIONS OF THE ASTRONOMICAL SOCIETY OF JAPAN, ASTRONOMICAL SOC JAPAN, ASCA OBSERVATIONS OF HARD X-RAY-EMISSION FROM THE RHO-OPHIUCHI DARK CLOUD, K KOYAMA; Y MAEDA; M OZAKI; S UENO; Y KAMATA; Y TAWARA; S SKINNER; S YAMAUCHI, ASCA obtained broad-band (0.8-12 keV) images and spectra of the central region of the Rho Ophiuchi dark cloud in 1993 August. The 38-ks observation detected at least eleven sources (S/N greater-than-or-equal-to 3), including the X-ray bright pre-main-sequence star DoAr 21 and embedded infrared sources with no optical counterparts. Hard X-rays up to almost-equal-to 8 keV were detected from DoAr 21 (whose light curve shows no evidence for variability) and from a flaring source lying in a region of high visual extinction. Thermal spectral fits for the brightest source give kT almost-equal-to 2 keV and hydrogen column densities N(H) almost-equal-to 1022 cm-2. The spectrum of a region in the center of the field where no discrete sources were detected shows hard, heavily absorbed emission that is most likely the integrated contribution of a number of deeply embedded young stars below the detection limit., 1994, 46, 3, L125, L129, Scientific journal

Refereed, PUBLICATIONS OF THE ASTRONOMICAL SOCIETY OF JAPAN, ASTRONOMICAL SOC JAPAN, GINGA OBSERVATIONS OF SN-1006 AND THE LUPUS REGION, M OZAKI; K KOYAMA; S UENO; S YAMAUCHI, X-rays from SN 1006 and the adjacent Lupus region were observed with Ginga. We found extended emission from the Lupus region, which could be described equally well by either a thermal bremsstrahlung model with kT = 7-10 keV or a power-law model with photon index of 2. An Fe line at an energy of about 6.2-6.4 keV with an equivalent width of 0.1-0.4 eV was also found. After subtracting this local background, the spectrum of SN 1006 was well fitted with a single power-law with index 3.2-3.3. The equivalent width of Fe K-emission line from SN 1006 is less than 120 eV (at the 90% confidence level)., 1994, 46, 4, 367, 373, Scientific journal

Refereed, PUBLICATIONS OF THE ASTRONOMICAL SOCIETY OF JAPAN, ASTRONOMICAL SOC JAPAN, GINGA OBSERVATION OF THE ORION-B CLOUD REGION, S YAMAUCHI; K KOYAMA; M INDAKOIDE, The Orion B cloud was observed with the Large Area Counter (LAC) onboard the X-ray satellite Ginga. Although the field of view of LAC included O-type stars, zeta Ori (O9.5 Ib) and sigma Ori (O9.5 V), as well as the Orion B cloud, the contributions of zeta Ori and sigma Ori were estimated to be less than approximately 34% of the observed count rate by both extrapolating the result of the Einstein Observatory of zeta Ori and assuming that both zeta Ori and sigma Ori have the same spectrum as that of delta Ori with a similar spectral type of O9.5 II. The X-ray spectrum after subtracting the contributions was well represented by a thin thermal plasma model with a temperature of 4.7 +/- 0.6 keV. The best-fit abundance of iron was 0.25 +/- 0.13 cosmic. Since many premain-sequence stars have been discovered in the Orion B cloud region, the origin of the thermal emission is considered to be the integrated emission from X-ray emitting pre-main-sequence stars embedded in the Orion B cloud. It follows from the results obtained in wide energy band observations that thermal emission with a temperature of several keV is a common characteristic of active star-forming regions., 1994, 46, 5, 473, 478, Scientific journal

Refereed, ASTROPHYSICAL JOURNAL, UNIV CHICAGO PRESS, HARD X-RAYS FROM THE ORION NEBULA REGION, S YAMAUCHI; K KOYAMA, Hard X-rays from the Orion Nebula region were observed with the X-ray satellite Ginga. The X-rays are associated with a small region near the Orion Trapezium and a more extended region around the Orion Nebula. The X-ray spectra from these two regions are represented by thermal bremsstrahlung models with an iron emission line at 6.7 keV. The temperature and luminosity in the 2-10 keV band from the Trapezium region are 2-3 keV and approximately 10(33) ergs s-1, respectively. Intensity variations of approximately 10% amplitude with a time scale of approximately 10(4) s were found. Therefore, a significant fraction of the X-ray flux is due to a point-source, possibly from the massive young star theta1 Ori C. The spatial distribution of the more extended region has an angular size of 2.-degrees-6 (FWHM) and is similar to the distribution of Halpha emission-line stars. Assuming that the extended X-ray emission is due to the Halpha emission line stars, the mean temperature and luminosity (in the 2-10 keV band) of the inidividual stars are estimated to be larger than 5 keV and approximately 6 x 10(30) ergs s-1, respectively., Mar. 1993, 405, 1, 268, 272, Scientific journal

Refereed, ASTROPHYSICAL JOURNAL, UNIV CHICAGO PRESS, THE 6.7 KEV IRON LINE DISTRIBUTION IN THE GALAXY, S YAMAUCHI; K KOYAMA, We have systematically observed the 6.7 keV iron line emission from the Galactic ridge with the X-ray satellite Ginga. The volume emissivity of the iron line emission from the Galactic ridge is approximated by an exponential disk model plus an arm component of Galactic radius 4 kpc. The scale height of the Galactic ridge emission is determined to be 100 +/- 20 pc. The iron line luminosity from the Galactic ridge is estimated to be (6.5 +/- 1.3) x 10(36) ergs s-1 , which is approximately 7% of the 2-10 keV band luminosity. We have also discovered another diffuse emission feature near the Galactic bulge with luminosity of about (2.8 +/- 0.8) x 10(36) ergs s-1. This emission is found to be extended to a higher Galactic latitude of more than 5-degrees., Feb. 1993, 404, 2, 620, 624, Scientific journal

Refereed, PUBLICATIONS OF THE ASTRONOMICAL SOCIETY OF JAPAN, ASTRONOMICAL SOC JAPAN, ON THE NATURE OF SCT X-1, S YAMAUCHI; K KOYAMA, A follow-up observation on the peculiar X-ray pulsar Sct X-1 was made. The X-ray flux was very weak (about 0.8 mCrab), and the X-ray spectrum exhibited a large absorption of about N(H) = 10(23) Hcm-2. We have confirmed coherent pulsation having a period of 111.194 +/- 0.003 s. Combined with the previous observation, this implies that the rate of the pulse period change (P) is 3.3 x 10(-9) s s-1. From the large P, we can say that Sct X-1 is more likely to be a neutron star binary than a DQ Her type star. Still, an additional pulse timing study for a time span longer than about 10 hr is necessary for a firm conclusion., 1993, 45, 3, 449, 452, Scientific journal

Refereed, PUBLICATIONS OF THE ASTRONOMICAL SOCIETY OF JAPAN, ASTRONOMICAL SOC JAPAN, HARD X-RAY-EMISSION FROM THE REGION NEAR THE SUPERNOVA REMNANT HB-9 AND THE RADIO GALAXY 4C-46.09, S YAMAUCHI; K KOYAMA, X-rays with energies greater than 1.5 keV near to the region of the supernova remnant HB 9 and the radio galaxy 4C 46.09 were observed with the X-ray satellite Ginga. The X-ray spectrum is represented by two-components models: a thin thermal emission at a low-energy band and a thermal emission or power-law model at a high-energy band. No significant emission line at 6.7 keV larger than 150 eV (90% upper-limit) of the equivalent width from highly ionized iron was detected. The best-fit thin thermal model has a temperature of 0.4-0.7 keV, which is attributable to the hot gas of HB 9. The hard component was found to have a temperature of 6.6 keV, or a photon index of 2.35. The N(H)-corrected flux in the 2-10 keV band is approximately 7 x 10(-12) erg s-1 cm-2. The origin of this component has remained unsolved. Several possibilities, such as the AGN activity from 4C 46.09, intracluser gas and the hard tail of HB 9 are discussed., 1993, 45, 4, 545, 550, Scientific journal

Refereed, PUBLICATIONS OF THE ASTRONOMICAL SOCIETY OF JAPAN, ASTRONOMICAL SOC JAPAN, X-RAY-SPECTRUM AND STRUCTURE OF THE SUPERNOVA REMNANT RX-04591+5147, S YAMAUCHI; S UENO; K KOYAMA; S NOMOTO; K HAYASHIDA; H TSUNEMI; ASAOKA, I, X-rays above 1.2 keV were observed near to the region of the supernova remnant RX 04591+5147, which was discovered by ROSAT. The scan profile in the 1.2-3 keV energy band shows extended emission which is consistent with the soft X-ray image observed with ROSAT. On the other hand, the scan profile above 3 keV shows a more complex structure with two bumps near to the north and south edges of the supernova remnant. The X-ray spectrum cannot be explained by the single-temperature thin thermal emission in the ionization equilibrium, but requires non-equilibrium ionization or a multi-temperature plasma. The iron K-line emission was discovered with the equivalent width of 140+/-90 eV (90% confidence). This also indicates that the supernova remnant has a higher temperature plasma than that determined by the ROSAT satellite. We suggest that a non-equilibrium inonization plasma can account for the overall X-ray properties over a wide energy range from the ROSAT to the Ginga bands., 1993, 45, 6, 795, 800, Scientific journal

Refereed, Astronomy and Astrophysics, X-ray spectroscopy of the young supernova remnant RCW 86, Kaastra, J. S; Asaoka, I; Koyama, K; Yamauchi, S, Jan. 1992, 264, 654-660, Scientific journal

Refereed, ASTROPHYSICAL JOURNAL, UNIV CHICAGO PRESS, OPTICALLY THIN HOT PLASMA NEAR THE GALACTIC-CENTER - MAPPING OBSERVATIONS OF THE 6.7 KEV IRON LINE, S YAMAUCHI; M KAWADA; K KOYAMA; H KUNIEDA; Y TAWARA; HATSUKADE, I, Dec. 1990, 365, 2, 532, 538, Scientific journal

Refereed, ASTROPHYSICAL JOURNAL, UNIV CHICAGO PRESS, HARD X-RAY-EMISSION FROM THE CARINA NEBULA, K KOYAMA; ASAOKA, I; N USHIMARU; S YAMAUCHI; RHD CORBET, Oct. 1990, 362, 1, 215, 218, Scientific journal

Refereed, NATURE, MACMILLAN MAGAZINES LTD, IS THE 5-KPC GALACTIC ARM A COLONY OF X-RAY PULSARS, K KOYAMA; M KAWADA; H KUNIEDA; Y TAWARA; Y TAKEUCHI; S YAMAUCHI, Jan. 1990, 343, 6254, 148, 149, Scientific journal

Refereed, PUBLICATIONS OF THE ASTRONOMICAL SOCIETY OF JAPAN, ASTRONOMICAL SOC JAPAN, GINGA OBSERVATION OF THE 2S 0114+650 SYSTEM, S YAMAUCHI; ASAOKA, I; M KAWADA; K KOYAMA; Y TAWARA, 1990, 42, 3, L53, L58

Refereed, PUBLICATIONS OF THE ASTRONOMICAL SOCIETY OF JAPAN, ASTRONOMICAL SOC JAPAN, NEW X-RAY SOURCES NEAR THE GALACTIC BULGE REGION, S YAMAUCHI; K KOYAMA, Nine new X-ray sources were discovered by the Ginga satellite during survey observations near the Galactic bulge region. Seven of the sources were found to have a hardness ratio similar to that of low-mass binary X-ray sources (LMXBs). One source has a hard spectrum with large low-energy absorption similar to that of X-ray pulsars. The other source, GS 1734-275, was found to be variable over a long time. It also exhibited an unusually soft spectrum, and, hence, could be a potential candidate for a black-hole binary. We also found that the EXOSAT new source, GPS 1742-326, has a typical LMXB spectrum., 1990, 42, 6, L83, L91

Refereed, NATURE, MACMILLAN MAGAZINES LTD, LARGE-SCALE EXTENDED X-RAY-EMISSION FROM THE VIRGO CLUSTER OF GALAXIES, S TAKANO; H AWAKI; K KOYAMA; H KUNIEDA; Y TAWARA; S YAMAUCHI; K MAKISHIMA; T OHASHI, Jul. 1989, 340, 6231, 289, 290, Scientific journal

Refereed, NATURE, MACMILLAN MAGAZINES LTD, INTENSE 6.7-KEV IRON LINE EMISSION FROM THE GALACTIC-CENTER, K KOYAMA; H AWAKI; H KUNIEDA; S TAKANO; Y TAWARA; S YAMAUCHI; HATSUKADE, I; F NAGASE, Jun. 1989, 339, 6226, 603, 605, Scientific journal

Refereed, PUBLICATIONS OF THE ASTRONOMICAL SOCIETY OF JAPAN, ASTRONOMICAL SOC JAPAN, DISCOVERY OF 413.9-2ND X-RAY PULSATION FROM X1722-36, Y TAWARA; S YAMAUCHI; H AWAKI; T KII; K KOYAMA; F NAGASE, 1989, 41, 3, 473, 481, Scientific journal

Refereed, Publications of the Astronomical Society of Japan, Oxford University Press (OUP), Discovery of recombining plasma associated with the candidate supernova remnant G189.6+3.3 with Suzaku, Shigeo Yamauchi; Moe Oya; Kumiko K Nobukawa; Thomas G Pannuti, We present the results of an X-ray spectral analysis of the northeast region of the candidate supernova remnant G189.6+3.3 with Suzaku. K-shell lines from highly ionized Ne, Mg, Si, and S were detected in the spectrum for the first time. In addition, a radiative recombining continuum (RRC) from He-like Si was clearly seen near 2.5 keV. This detection of an RRC reveals for the first time that G189.6+3.3 possesses an X-ray-emitting recombining plasma (RP). The extracted X-ray spectrum in the 0.6–10.0 keV energy band is well fitted with a model consisting of a collisional ionization equilibrium plasma component (associated with the interstellar medium) and an RP component (associated with the ejecta). The spectral feature shows that G189.6+3.3 is most likely to be a middle-aged SNR with an RP., 02 Oct. 2020, 72, 5, Scientific journal, 10.1093/pasj/psaa070

Refereed, Publications of the Astronomical Society of Japan, Oxford University Press (OUP), X-ray emission from the mixed-morphology supernova remnant HB 9, Mariko Saito; Shigeo Yamauchi; Kumiko K Nobukawa; Aya Bamba; Thomas G Pannuti, We present the results of a spectral analysis of the central region of the mixed-morphology supernova remnant HB 9. A prior Ginga observation of this source detected a hard X-ray component above 4 keV, and the origin of this particular X-ray component is still unknown. Our results demonstrate that the extracted X-ray spectra are best represented by a model consisting of a collisional ionization equilibrium plasma with a temperature of ∼0.1–0.2 keV (interstellar matter component) and an ionizing plasma with a temperature of ∼0.6–0.7 keV and an ionization timescale of &gt;1 × 1011 cm−3 s (ejecta component). No significant X-ray emission was found in the central region above 4 keV. The recombining plasma model reported by a previous work does not explain our spectra., 01 Aug. 2020, 72, 4, Scientific journal, 10.1093/pasj/psaa042

Refereed, Publications of the Astronomical Society of Japan, Oxford University Press (OUP), Discovery of annular X-ray emission centered on MAXI J1421-613: Dust-scattering X-rays?, Kumiko K Nobukawa; Masayoshi Nobukawa; Shigeo Yamauchi, We report the discovery of an annular emission of $\sim\!\! {3^{\prime } }\!-\!{9^{\prime } }$ radius around the center of a transient source, the X-ray burster MAXI J1421-613, in the Suzaku follow-up analysis. The spectrum of the annular emission shows no significant emission-line structure, and is well explained by an absorbed power-law model with a photon index of $\sim\!\! 4.2$. These features exclude the possibility that the annular emission is a shell-like component of a supernova remnant. The spectral shape, the time history, and the X-ray flux of the annular emission agree with the scenario that the emission is due to a dust-scattering echo. The annular emission is made under a rare condition of the dust-scattering echo, where the central X-ray source, MAXI J1421-613, exhibits a short time outburst with three X-ray bursts and immediately re-enters a long quiescent period. The distribution of the hydrogen column density along the annular emission follows that of the CO intensity, which means that MAXI J1421-613 is located behind the CO cloud. We estimate the distance to MAXI J1421-613 to be $\sim\!\! 3\:$kpc assuming that the dust layer responsible for the annular emission is located at the same position as the CO cloud., 01 Apr. 2020, 72, 2, Scientific journal, 10.1093/pasj/psaa007

Refereed, Publications of the Astronomical Society of Japan, Oxford University Press (OUP), Spectral and timing properties of the black hole candidate X1755−338 observed in 1989–1995, Shigeo Yamauchi; Sakiho Maeda, We report results of an analysis of the black hole (BH) candidate source X1755−338 made in 1989, 1990, and 1991 with Ginga, and in 1995 with ASCA. The spectra were well represented by a model consisting of a soft thermal emission from an accretion disk and a hard X-ray tail. The normalization of the multi-color disk, related to the inner disk radius, was similar to each other. The unabsorbed X-ray fluxes from the disk component in the 0.01–10 keV band were estimated to be 1.3 × 10−9, 3.0 × 10−9, 9.8 × 10−10, and 2.4 × 10−9 erg s−1 cm−2 in 1989, 1990, 1991, and 1995, respectively, and are proportional to $kT_{\rm in}^4$, where kTin is a temperature at the inner disk radius. Based on the standard accretion disk model for a non-rotating BH, our results suggest either a small BH mass or a large inclination angle. Otherwise, X1755−338 is a rotating BH. The hard X-ray intensity was found to be variable, while the soft X-ray intensity was stable. Although previous work showed the existence of an iron line at 6.7 keV, no clear iron line feature was found in any of the spectra. We infer that most of the iron line flux reported in the previous work was due to contamination of the Galactic diffuse X-ray emission., 04 Aug. 2021, 73, 4, 830, 836, Scientific journal, 10.1093/pasj/psab048

Refereed, Journal of Astronomical Telescopes, Instruments, and Systems, SPIE-Intl Soc Optical Eng, Detail Design of the Science Operations for the XRISM mission, Yukikatsu Terada; Matt Holland; Michael Loewenstein; Makoto Tashiro; Hiromitsu Takahashi; Masayoshi Nobukawa; Tsunefumi Mizuno; Takayuki Tamura; Shin’ichiro Uno; Shin Watanabe; Chris Baluta; Laura Burns; Ken Ebisawa; Satoshi Eguchi; Yasushi Fukazawa; Katsuhiro Hayashi; Ryo Iizuka; Satoru Katsuda; Takao Kitaguchi; Aya Kubota; Eric Miller; Koji Mukai; Shinya Nakashima; Kazuhiro Nakazawa; Hirokazu Odaka; Masanori Ohno; Naomi Ota; Rie Sato; Makoto Sawada; Yasuharu Sugawara; Megumi Shidatsu; Tsubasa Tamba; Atsushi Tanimoto; Yuichi Terashima; Yohko Tsuboi; Yuusuke Uchida; Hideki Uchiyama; Shigeo Yamauchi; Tahir Yaqoob, Jul. 2021, 7, 03, 037001, Scientific journal, 10.1117/1.jatis.7.3.037001

Refereed, Publications of the Astronomical Society of Japan, Oxford University Press (OUP), A systematic comparison of ionization temperatures between ionizing and recombining plasmas in supernova remnants, Shigeo Yamauchi; Masayoshi Nobukawa; Katsuji Koyama, The temperatures of the plasma in supernova remnants (SNRs) are initially very low just after the shock heating. The electron temperature (kTe) increases quickly by Coulomb interaction, and then the energetic electrons gradually ionize atoms to increase the ionization temperature (kTi). The observational fact is that most young and middle-to-old SNRs have lower kTi than kTe after the shock heating. The temperature evolution in shell-like SNRs has been explained by this ionizing plasma (IP) scenario. On the other hand, in the last decade, a significant fraction of mixed-morphology SNRs was found to exhibit a recombining plasma (RP) with higher kTi than kTe. The origin and the evolution mechanism of RP SNRs have been puzzling. To address this puzzle, this paper presents kTe and kTi profiles using follow-up Suzaku observations, and then proposes a new scenario for the temperature and morphology evolution in IP and RP SNRs., 13 Jun. 2021, 73, 3, 728, 734, Scientific journal, 10.1093/pasj/psab033

Space Telescopes and Instrumentation 2020: Ultraviolet to Gamma Ray, SPIE, The XRISM science data center: optimizing the scientific return from a unique x-ray observatory, Michael Loewenstein; Robert S. Hill; Matthew P. Holland; Eric D. Miller; Tahir Yaqoob; Trisha F. Doyle; Patricia L. Hall; Efrem Braun; Christopher J. Baluta; Koji Mukai; Yukikatsu Terada; Makoto S. Tashiro; Hiromitsu Takahashi; Masayoshi Nobukawa; Tsunefumi Mizuno; Takayuki Tamura; Shin'ichiro Uno; Shin Watanabe; Ken Ebisawa; Satoshi Eguchi; Yasushi Fukazawa; Ryo Iizuka; Satoru Katsuda; Takao Kitaguchi; Aya Kubota; Shinya Nakashima; Kazuhiro Nakazawa; Hirokazu Odaka; Masanori Ohno; Naomi Ota; Rie Sato; Yasuharu Sugawara; Megumi Shidatsu; Tsubasa Tamba; Yuichi Terashima; Yohko Tsuboi; Yuusuke Uchida; Hideki Uchiyama; Shigeo Yamauchi, 13 Dec. 2020, International conference proceedings, 10.1117/12.2560840

Space Telescopes and Instrumentation 2020: Ultraviolet to Gamma Ray, SPIE, Status of x-ray imaging and spectroscopy mission (XRISM), Makoto S. Tashiro; Hironori Maejima; Kenichi Toda; Richard L. Kelley; Lillian Reichenthal; Leslie Hartz; Robert Petre; Brian J. Williams; Matteo Guainazzi; Elisa Costantini; Ryuichi Fujimoto; Kiyoshi Hayashida; Joy Henegar-Leon; Matt Holland; Yoshitaka Ishisaki; Caroline Kilbourne; Mike Loewenstein; Kyoko Matsushita; Koji Mori; Takashi Okajima; F. Scott Porter; Gary Sneiderman; Yoh Takei; Yukikatsu Terada; Hiroshi Tomida; Hiroya Yamaguchi; Shin Watanabe; Hiroki Akamatsu; Yoshitaka Arai; Marc Audard; Hisamitsu Awaki; Iurii Babyk; Aya Bamba; Nobutaka Bando; Ehud Behar; Thomas Bialas; Rozenn Boissay-Malaquin; Laura Brenneman; Greg Brown; Edgar Canavan; Meng Chiao; Brian Comber; Lia Corrales; Renata Cumbee; Cor de Vries; Jan-Willem den Herder; Johannes Dercksen; Maria Diaz-Trigo; Michael DiPirro; Chris Done; Tadayasu Dotani; Ken Ebisawa; Megan Eckart; Dominique Eckert; Satoshi Eguchi; Teruaki Enoto; Yuichiro Ezoe; Carlo Ferrigno; Yutaka Fujita; Yasushi Fukazawa; Akihiro Furuzawa; Luigi Gallo; Nathalie Gorter; Martin Grim; Liyi Gu; Kouichi Hagino; Kenji Hamaguchi; Isamu Hatsukade; David Hawthorn; Katsuhiro Hayashi; Natalie Hell; Junko Hiraga; Edmund Hodges-Kluck; Takafumi Horiuchi; Ann Hornschemeier; Akio Hoshino; Yuto Ichinohe; Sayuri Iga; Ryo Iizuka; Manabu Ishida; Naoki Ishihama; Kumi Ishikawa; Kosei Ishimura; Tess Jaffe; Jelle Kaastra; Timothy Kallman; Erin Kara; Satoru Katsuda; Steven Kenyon; Mark Kimball; Takao Kitaguti; Shunji Kitamoto; Shogo Kobayashi; Akihide Kobayashi; Takayoshi Kohmura; Aya Kubota; Maurice Leutenegger; Muzi Li; Tom Lockard; Yoshitomo Maeda; Maxim Markevitch; Connor Martz; Hironori Matsumoto; Keiichi Matsuzaki; Dan McCammon; Brian McLaughlin; Brian McNamara; Joseph Miko; Eric Miller; Jon Miller; Kenji Minesugi; Shinji Mitani; Ikuyuki Mitsuishi; Misaki Mizumoto; Tsunefumi Mizuno; Koji Mukai; Hiroshi Murakami; Richard Mushotzky; Hiroshi Nakajima; Hideto Nakamura; Kazuhiro Nakazawa; Chikara Natsukari; Kenichiro Nigo; Yusuke Nishioka; Kumiko Nobukawa; Masayoshi Nobukawa; Hirofumi Noda; Hirokazu Odaka; Mina Ogawa; Takaya Ohashi; Masahiro Ohno; Masayuki Ohta; Atsushi Okamoto; Naomi Ota; Masanobu Ozaki; Stephane Paltani; Paul Plucinsky; Katja Pottschmidt; Michael Sampson; Takahiro Sasaki; Kosuke Sato; Rie Sato; Toshiki Sato; Makoto Sawada; Hiromi Seta; Yasuko Shibano; Maki Shida; Megumi Shidatsu; Shuhei Shigeto; Keisuke Shinozaki; Peter Shirron; Aurora Simionescu; Randall Smith; Kazunori Someya; Yang Soong; Keisuke Sugawara; Yasuharu Sugawara; Andy Szymkowiak; Hiromitsu Takahashi; Toshiaki Takeshima; Toru Tamagawa; Keisuke Tamura; Takaaki Tanaka; Atsushi Tanimoto; Yuichi Terashima; Yohko Tsuboi; Masahiro Tsujimoto; Hiroshi Tsunemi; Takeshi Tsuru; Hiroyuki Uchida; Yuusuke Uchida; Hideki Uchiyama; Yoshihiro Ueda; Shinichiro Uno; Jacco Vink; Tomomi Watanabe; Michael Wittheof; Rob Wolfs; Shinya Yamada; Kazutaka Yamaoka; Noriko Yamasaki; Makoto Yamauchi; Shigeo Yamauchi; Keiichi Yanagase; Tahir Yaqoob; Susumu Yasuda; Tessei Yoshida; Nasa Yoshioka; Irina Zhuravleva, 13 Dec. 2020, International conference proceedings, 10.1117/12.2565812

Proceedings of SPIE - The International Society for Optical Engineering, Detail plans and preparations for the science operations of the XRISM mission, Yukikatsu Terada; Matt Holland; Michael Loewenstein; Makoto Tashiro; Hiromitsu Takahashi; Masayoshi Nobukawa; Tsunefumi Mizuno; Takayuki Tamura; Shin'ichiro Uno; Shin Watanabe; Chris Baluta; Laura Burns; Ken Ebisawa; Satoshi Eguchi; Yasushi Fukazawa; Katsuhiro Hayashi; Ryo Iizuka; Satoru Katsuda; Takao Kitaguchi; Aya Kubota; Eric Miller; Koji Mukai; Shinya Nakashima; Kazuhiro Nakazawa; Hirokazu Odaka; Masanori Ohno; Naomi Ota; Rie Sato; Yasuharu Sugawara; Megumi Shidatsu; Tsubasa Tamba; Atsushi Tanimoto; Yuichi Terashima; Yohko Tsuboi; Yuusuke Uchida; Hideki Uchiyama; Shigeo Yamauchi; Tahir Yaqoob, © 2020 SPIE The XRISM is the X-ray astronomical mission led by JAXA/NASA/ESA with international participation, plan to be launched in 2022 (Japanese fiscal year), to quickly recover the high-resolution X-ray spectroscopy of astrophysical objects using the micro-calorimeter array after the failure of Hitomi. To enhance the scientific outputs of the mission, the Science Operations Team (SOT) is structured independently from the instrument teams and the mission operation team (MOT). The responsibilities of the SOT are summarized into four categories: 1) Guest observer program and data distributions, 2) Distribution of the analyses software and calibration database, 3) Guest observer supporting activities, and 4) the performance verification and optimization (PVO) activities. Before constructing the Operations Concept of the XRISM mission, the lessons on the Science Operations learned from the past Japanese X-ray missions (ASCA, Suzaku, and Hitomi) are reviewed, and 16 kinds of lessons are identified by the above categories: lessons on the importance of avoiding nonpublic (“animal”) tools, coding quality of public tools both on the engineering viewpoint and the calibration accuracy, tight communications with instrument teams and operations team, well-defined task division between scientists and engineers etc. Among these lessons, a) importance of the early preparations of the operations from the ground stage, b) construction of the independent team for the Science Operations from the instrument developments, and c) operations with well-defined duties by appointed members are recognized as the key lessons for XRISM. Then, i) the task division between the Mission and Science Operations and ii) the subgroup structure within the XRISM team are defined in detail as the XRISM Operations Concept. Then, following the Operations Concept, the detail plan of the Science Operations is designed as follows. The Science Operations tasks are shared among Japan, US, and Europe operated by three centers, the Science Operations Center (SOC) at JAXA, the Science Data Center (SDC) at NASA, and European Space Astronomy Centre (ESAC) at ESA. The SOT is defined as a combination of the SOC and SDC; the SOC is designed to perform tasks close to the spacecraft operations, such as spacecraft planning of science targets, quick-look health checks, pre-pipeline data processing, etc., and the SDC covers the tasks on the data calibration processing (pipeline processing), maintenance of the analysis tools etc. The data-archive and users-support activities are planned to be covered both by the SOC and SDC. Finally, the details of the Science Operations tasks and the tools for the Science Operations are also described in this paper. This information would be helpful for a construction of Science Operations of future X-ray missions., 2020, 11444, International conference proceedings, 10.1117/12.2560861

JOURNAL OF ASTRONOMICAL TELESCOPES INSTRUMENTS AND SYSTEMS, SPIE-SOC PHOTO-OPTICAL INSTRUMENTATION ENGINEERS, Supermirror design for Hard X-Ray Telescopes on-board Hitomi (ASTRO-H), Keisuke Tamura; Hideyo Kunieda; Yusuke Miyata; Takashi Okajima; Takuya Miyazawa; Akihiro Furuzawa; Hisamitsu Awaki; Yoshito Haba; Kazunori Ishibashi; Manabu Ishida; Yoshitomo Maeda; Hideyuki Mori; Yuzuru Tawara; Shigeo Yamauchi; Kentaro Uesugi; Yoshio Suzuki, We designed depth-graded multilayers, so-called supermirrors, with platinum/carbon (Pt/C) layer pairs for the Hard X-Ray Telescope (HXT) that was on-board the sixth Japanese X-Ray Astronomy Satellite Hitomi (ASTRO-H). The HXT has multinested thin foil optics, and the grazing angles of the x-ray mirrors are 0.07 to 0.27 deg. Supermirrors for HXTs are designed to provide a broad energy response (up to 80 keV) for astronomical requests. Under practical boundary conditions, we establish a block method applying empirical rules to maximize the integrated reflectivity. We fabricated Pt/C supermirrors using a DC magnetron sputtering system. The reflectivity of the mirrors was measured in a synchrotron radiation facility, SPring-8. We describe the design method for the supermirrors and our results. (C) The Authors. Published by SPIE under a Creative Commons Attribution 3.0 Unported License., Jan. 2018, 4, 1, Scientific journal, 10.1117/1.JATIS.4.1.011209

Not Refereed, ASTRONOMISCHE NACHRICHTEN, WILEY-V C H VERLAG GMBH, X-ray lobes of W 50/SS 433 system, M Namiki; N Kawai; T Kotani; S Yamauchi; W Brinkmann, The X-ray lobes (ie on both sides feast and west) of SS 433, and are presumably produced by the interaction of the jets of SS 433 with the surrounding SNR W 50. The non-thermal nature of the east lobe has been reported by Yamauchi et al. (1994) using ASCA data. With the further ASCA observations, we studied the spectra and morphology of both the east and nest lobes in detail. Their spectra have no emission lines, and are well described by power-lam models with interstellar absorption. The X-ray emission becomes softer on both sides with increasing distance from SS 433. The X-ray surface brightness peaks closer to SS 433 in the high-energy band than in the low energy band, suggesting that the high energy electrons in the X-ray lobes lose energies by synchrotron emission as they travel away from SS 433. We estimate the magnetic field and the total energy of the high energy electrons to be similar to 2 mu G and similar to 5 x 10(46) erg, respectively., 1999, 320, 4-5, 326, 326, Scientific journal

Refereed, Publications of the Astronomical Society of Japan, Oxford University Press (OUP), Suzaku observations of Fe K-shell lines in the supernova remnant W 51 C and hard X-ray sources in the proximity, Aika Shimaguchi; Kumiko K Nobukawa; Shigeo Yamauchi; Masayoshi Nobukawa; Yutaka Fujita, Abstract In this paper, we investigate the Fe K-shell lines in the supernova remnant W 51 C and hard X-ray sources in the proximity. We measure the intensities of the Fe i Kα and Fe xxv Heα lines at 6.40 and 6.68 keV, respectively, and find that the intensity of the 6.68 keV line is consistent with the background level expected from previous studies, while that of the 6.40 keV line is higher at the significance level of 2.0σ. Given the presence of gamma-ray emission and high ionization rate point spatially coincident with the remnant, we conclude that the enhanced 6.40 keV line most likely originates from the interaction between low-energy cosmic rays and molecular clouds. Also, we discover an enhanced 6.68 keV line emission from the compact H ii region G49.0−0.3 at a significance level of 3.4σ. Spectral analysis reveals that the temperature and abundance of the thermal plasma with the 6.68 keV line is $kT=3.0^{+0.8}_{-0.7}$ keV and Z = 0.5 ± 0.2 solar, respectively. These values are explained by the thermal plasma generated by the stellar winds of O stars., 02 Jun. 2022, 74, 3, 656, 663, Scientific journal, 10.1093/pasj/psac026

Refereed, Advances in Space Research, Elsevier BV, Confirmation of dust scattering echo around MAXI J1421–613 by Swift observation, Kumiko K. Nobukawa; Masayoshi Nobukawa; Shigeo Yamauchi, Jan. 2023, 71, 1074, 1079, Scientific journal, 10.1016/j.asr.2022.09.003

Space Telescopes and Instrumentation 2022: Ultraviolet to Gamma Ray, SPIE, Xappl: software framework for the XRISM pre-pipeline, Satoshi Eguchi; Makoto Tashiro; Yukikatsu Terada; Hiromitsu Takahashi; Masayoshi Nobukawa; Tsunefumi Mizuno; Shin'ichiro Uno; Aya Kubota; Kazuhiro Nakazawa; Shin Watanabe; Ryo Iizuka; Rie Sato; Tomokage Yoneyama; Chris Baluta; Ken Ebisawa; Yasushi Fukazawa; Katsuhiro Hayashi; So Kato; Satoru Katsuda; Takao Kitaguchi; Hirokazu Odaka; Masanori Ohno; Naomi Ota; Minami Sakama; Ryohei Sato; Megumi Shidatsu; Yasuharu Sugawara; Tsubasa Tamba; Atsushi Tanimoto; Yuichi Terashima; Yohko Tsuboi; Nagomi Uchida; Yuusuke Uchida; Hideki Uchiyama; Shigeo Yamauchi; Masaaki Sakano; Tessei Yoshida; Satoshi Yamada, 31 Aug. 2022, International conference proceedings, 10.1117/12.2629316

Refereed, Publications of the Astronomical Society of Japan, Oxford University Press (OUP), Initial state of the recombining plasma in supernova remnant W 28, Rui Himono; Masayoshi Nobukawa; Shigeo Yamauchi; Kumiko K Nobukawa; Nari Suzuki, Abstract We have investigated supernova remnant (SNR) W 28 using Suzaku archival data, and we report here the results of our spatially resolved analyses. We carried out spectral analyses using a recombining-plasma (RP) model with element-dependent initial ionization temperatures, obtaining ∼0.5 keV for Ne, ∼0.7 keV for Mg, ∼1.0 keV for Si, ∼1.2 keV for S, ∼1.4 keV for Ar, ∼1.7 keV for Ca, and ∼0.7 keV for Fe in the initial RP phase. In addition to the north-east regions where RPs have been reported previously, we find that the ionization temperatures in the south-east and south-west regions exhibit trends that are similar to those in the central region in the initial RP phase. We also find that the time elapsed from the initial phase of the RP to the present is shorter in the central region, ∼300 yr, and longer in the outside regions, ∼103–104 yr. Our results cannot be explained by simple scenarios involving thermal conduction into molecular clouds or by adiabatic cooling (due to rarefaction), indicating that more complex mechanisms or other scenarios are required. We also estimate the ejecta mass to be ≳14 M⊙, which indicates that this SNR was produced by a massive star., 08 Feb. 2023, Scientific journal, 10.1093/pasj/psad005

Refereed, Publications of the Astronomical Society of Japan, Oxford University Press (OUP), Spectral study of the Galactic ridge X-ray emission with Suzaku: Comparison of the spectral shape with point sources, Kumiko Yamamoto; Shigeo Yamauchi; Masayoshi Nobukawa; Kumiko K Nobukawa; Hideki Uchiyama, Abstract The Galactic ridge X-ray emission (GRXE) is unresolved X-ray emission located on the Galactic plane, and whether the GRXE comes from truly diffuse plasma or unresolved point sources is still debatable. We present results of spectral analysis of the GRXE with Suzaku. In order to examine the point source origin, we fitted the GRXE spectra in the 1.2–10 keV energy band with a point source model, which is a mixture of active binary stars (ABs) and non-magnetic cataclysmic variables (non-mCVs), and found that the model cannot represent the GRXE spectral shape as long as the standard metal abundances of these species are assumed. In particular, the standard abundance model cannot account for the observed intensities of Si, S, and Ar lines as well as the previously reported Fe line. Assuming spatial densities in the solar neighborhood, integration of the ABs and non-mCVs accounts for only 30% of the observed GRXE flux. Other species of the point sources or diffuse emission with stronger Si, S, Ar, and Fe emission lines shall explain the rest., 20 Mar. 2023, Scientific journal, 10.1093/pasj/psad016

Refereed, Publications of the Astronomical Society of Japan, Oxford University Press (OUP), Suzaku spectral analysis of an X-ray emitting plasma in the supernova remnant G352.7−0.1, Asahi Fujishige; Shigeo Yamauchi; Kumiko K Nobukawa; Masayoshi Nobukawa, Abstract The results of a Suzaku observation of the supernova remnant (SNR) G352.7−0.1 are presented in this paper. We conducted spectral analysis based on careful sky background estimation and found an emission line from Al at 1.6 keV, in addition to previously detected emission lines from Mg, Si, S, Ar, Ca, and Fe ions. The X-ray spectrum in the 0.7–10 keV band is represented by a two-component ionizing plasma model with different temperatures and ionization timescales. Based on the results, properties of the X-ray emitting plasma and the explosion type are discussed., 25 Jul. 2023, 75, 5, 907, 912, Scientific journal, 10.1093/pasj/psad048

Refereed, Publications of the Astronomical Society of Japan, Oxford University Press (OUP), Spectral analysis of the Galactic supernova remnant Kesteven 69 with Suzaku, Shigeo Yamauchi; Thomas G Pannuti, Abstract The results of a Suzaku observation of the supernova remnant (SNR) Kesteven 69 = G21.8−0.6 are presented. To estimate the sky background precisely, we conducted a simultaneous fit of the source region spectrum with the background region spectrum and found that the SNR spectrum is well represented by a two-component ionizing plasma model composed of a low-temperature plasma at kTe = 0.80 ± 0.11 keV and a high-temperature plasma at kTe = 1.5 ± 0.4 keV. The existence of a low-ionized Fe K line at 6.49 ± 0.07 keV was confirmed. The center energy of the line is consistent with those of type Ia SNRs., 09 Oct. 2023, 75, 6, 1273, 1279, Scientific journal, 10.1093/pasj/psad068

Refereed, 2007 IEEE NUCLEAR SCIENCE SYMPOSIUM CONFERENCE RECORD, VOLS 1-11, IEEE, In-flight status of the X-ray observatory Suzaku, T. Dotani; K. Mitsuda; M. Bautz; H. Inoue; R. L. Kelley; K. Koyama; H. Kunieda; K. Makishima; Y. Ogawara; R. Petre; T. Takahashi; H. Tsunemi; N. E. White; N. Anabuki; L. Angelini; K. Arnaud; H. Awaki; A. Bamba; K. Boyce; G. V. Brown; K. -W. Chan; J. Cottam; J. Doty; K. Ebisawa; Y. Ezoe; A. C. Fabian; E. Figueroa; R. Fujimoto; Y. Fukazawa; T. Furusho; A. Furuzawa; K. Gendreau; R. E. Griffiths; Y. Haba; K. Hamaguchi; l. Harrus; G. Hasinger; I. Hatsukade; K. Hayashida; P. J. Henry; J. S. Hiraga; S. S. Holt; A. Hornschemeier; J. P. Hughes; U. Hwang; M. Ishida; Y. Ishisaki; N. Isobe; M. Itoh; N. Iyomoto; S. M. Kahn; T. Kamae; H. Katagiri; J. Kataoka; H. Katayama; N. Kawai; M. Kawaharada; C. Kilbourne; K. Kinugasa; S. Kissel; S. Kitamoto; M. Kohama; T. Kohmura; M. Kokubun; T. Kotani; J. Kotoku; A. Kubota; G. M. Madejski; Y. Maeda; F. Makino; A. Markowitz; C. Matsumoto; H. Matsumoto; M. Matsuoka; K. Matsushita; D. McCammon; T. Mihara; K. Misaki; E. Miyata; T. Mizuno; K. Mori; H. Mori; M. Morii; H. Moseley; K. Mukai; H. Murakami; T. Murakami; R. Mushotzky; F. Nagase; M. Namiki; H. Negoro; K. Nakazawa; J. A. Nousek; T. Okajima; Y. Ogasaka; T. Ohashi; T. Oshima; N. Ota; M. Ozaki; H. Ozawa; A. N. Parmar; W. D. Pence; F. Scott Porter; J. N. Reeves; G. R. Ricker; L. Sakurai; W. T. Sanders; A. Senda; P. Serlemitsos; R. Shibata; K. Shinozaki; Y. Soong; R. Smith; M. Suzuki; A. E. Szymkowiak; H. Takahashi; Y. Takei; T. Tamagawa; K. Tamura; T. Tamura; Y. Tanaka; M. Tashiro; Y. Tawara; Y. Terada; Y. Terashima; H. Tomida; K. Torii; Y. Tsuboi; Y. Tsujimoto; T. Tsuru; M. J. L. Turner; Y. Uchiyama; Y. Ueda; S. Ueno; M. Ueno; S. Uno; Y. Urata; S. Watanabe; N. Yamamoto; K. Yamaoka; N. Y. Yamasaki; K. Yamashita; M. Yamauchi; S. Yajmauchi; T. Yaqoob; D. Yonetoku; A. Yoshida, We report in-flight status of the X-ray detectors on board the Suzaku observatory, the 5th X-ray astronomy satellite of Japan launched on July 10, 2005. Suzaku is equipped with two types of instruments: one is the X-ray Imaging Spectrometers (XISs) and the other is Hard X-ray Detector (HXD). XIS utilizes the X-ray CCD camera in combination with the grazing-incidence X-ray telescope. HXD is a non-imaging, hybrid detector utilizing Si PIN diodes and GSO/BGO phoswich counters. Suzaku takes a low-earth, circular orbit with an altitude of 560 km and an inclination of 31 deg. This means that Suzaku goes through the south atlantic anomaly about 1/3 of its revolutions. This has a large impact on the in-flight performance of XIS and HXD, which is reported in detail in the present paper., 2007, 2526, +, International conference proceedings

Refereed, Publications of the Astronomical Society of Japan, Oxford University Press (OUP), Detection of the neutral iron line from the supernova remnant W 49 B with Suzaku, Nari Suzuki; Shigeo Yamauchi; Kumiko K Nobukawa; Masayoshi Nobukawa; Satoru Katsuda, Abstract Recent studies of supernova remnants (SNRs) have revealed that some SNRs exhibit a neutral iron line emission at 6.4 keV. This line has been proposed to originate from the interaction of high-energy particles formed in the SNR shell with the surrounding cold matter. We searched for the neutral iron line emission in the SNR W 49 B. Significant detection of the 6.4 keV line is found in the north-west region, close to the molecular cloud interacting with the SNR shell. In addition, an excess emission at 8–9 keV, in which Kγ, Kδ, and Kϵ lines of He-like iron exist, is also significantly found in the region where the radio shell is not bright. We discuss the origin of the 6.4 keV line and the excess emission at 8–9 keV., 08 Feb. 2024, 76, 2, 265, 271, Scientific journal, 10.1093/pasj/psae006

Refereed, Publications of the Astronomical Society of Japan, Oxford University Press (OUP), Suzaku observation of an iron K-shell line in the spiral galaxy NGC 6946, Shigeo Yamauchi; Azusa Inaba; Yumiko Anraku, Abstract An emission line at ∼6.7 keV is attributable to an He-like iron K-shell transition, which indicates existence of a thin thermal plasma with a temperature of several keV. Using Suzaku archival data, we searched for the iron K-line from the spiral galaxy NGC 6946, and found it at 6.68 ± 0.07 keV at the 3.1σ level in the central $r\le {2.^{\prime }5}$ region. The iron line luminosity from the central region was estimated to be (2.3 ± 1.2) × 1037 erg s−1 at a distance of 5.5 Mpc. The origin of the iron emission line is discussed., 07 May 2024, 76, 3, 523, 527, Scientific journal, 10.1093/pasj/psae028

Not Refereed, SPACE TELESCOPES AND INSTRUMENTATION 2018: ULTRAVIOLET TO GAMMA RAY, SPIE-INT SOC OPTICAL ENGINEERING, Concept of X-ray Astronomy Recovery Mission, Makoto Tashiro; Hironori Maejima; Kenichi Toda; Richard Kelley; Lillian Reichenthal; James Lobell; Robert Petre; Matteo Guainazzi; Elisa Costantini; Mark Edison; Ryuichi Fujimoto; Martin Grim; Kiyoshi Hayashida; Jan-Willem den Herder; Yoshitaka Ishisaki; Stephane Paltani; Kyoko Matsushita; Koji Mori; Gary Sneiderman; Yoh Takei; Yukikatsu Terada; Hiroshi Tomida; Hiroki Akamatsu; Lorella Angelini; Yoshitaka Arai; Hisamitsu Awaki; Iurii Babyk; Aya Bamba; Peter Barfknecht; Kim Barnstable; Thomas Bialas; Branimir Blagojevic; Joseph Bonafede; Clifford Brambora; Laura Brenneman; Greg Brown; Kimberly Brown; Laura Burns; Edgar Canavan; Tim Carnahan; Meng Chiao; Brian Comber; Lia Corrales; Cor de Vries; Johannes Dercksen; Maria Diaz-Trigo; Tyrone Dillard; Michael DiPirro; Chris Done; Tadayasu Dotani; Ken Ebisawa; Megan Eckart; Teruaki Enoto; Yuichiro Ezoe; Carlo Ferrigno; Yutaka Fujita; Yasushi Fukazawa; Akihiro Furuzawa; Luigi Gallo; Steve Graham; Liyi Gu; Kohichi Hagino; Kenji Hamaguchi; Isamu Hatsukade; Dean Hawes; Takayuki Hayashi; Cailey Hegarty; Natalie Hell; Junko Hiraga; Edmund Hodges-Kluck; Matt Holland; Ann Hornschemeier; Akio Hoshino; Yuto Ichinohe; Ryo Iizuka; Kazunori Ishibashi; Manabu Ishida; Kumi Ishikawa; Kosei Ishimura; Bryan James; Timothy Kallman; Erin Kara; Satoru Katsuda; Steven Kenyon; Caroline Kilbourne; Mark Kimball; Takao Kitaguchi; Shunji Kitamoto; Shogo Kobayashi; Takayoshi Kohmura; Shu Koyama; Aya Kubota; Maurice Leutenegger; Tom Lockard; Mike Loewenstein; Yoshitomo Maeda; Lynette Marbley; Maxim Markevitch; Connor Martz; Hironori Matsumoto; Keiichi Matsuzaki; Dan McCammon; Brian McNamara; Joseph Miko; Eric Miller; Jon Miller; Kenji Minesugi; Ikuyuki Mitsuishi; Tsunefumi Mizuno; Hideyuki Mori; Koji Mukai; Hiroshi Murakami; Richard Mushotzky; Hiroshi Nakajima; Hideto Nakamura; Shinya Nakashima; Kazuhiro Nakazawa; Chikara Natsukari; Kenichiro Nigo; Yusuke Nishioka; Kumiko Nobukawa; Masayoshi Nobukawa; Hirofumi Noda; Hirokazu Odaka; Mina Ogawa; Takaya Ohashi; Masahiro Ohno; Masayuki Ohta; Takashi Okajima; Atsushi Okamoto; Michitaka Onizuka; Naomi Ota; Masanobu Ozaki; Paul Plucinsky; F. Scott Porter; Katja Pottschmidt; Kosuke Sato; Rie Sato; Makoto Sawada; Hiromi Seta; Ken Shelton; Yasuko Shibano; Maki Shida; Megumi Shidatsu; Peter Shirron; Aurora Simionescu; Randall Smith; Kazunori Someya; Yang Soong; Yasuharu Sugawara; Andy Szymkowiak; Hiromitsu Takahashi; Toru Tamagawa; Takayuki Tamura; Takaaki Tanaka; Yuichi Terashima; Yohko Tsuboi; Masahiro Tsujimoto; Hiroshi Tsunemi; Takeshi Tsuru; Hiroyuki Uchida; Hideki Uchiyama; Yoshihiro Ueda; Shinichiro Uno; Thomas Walsh; Shin Watanabe; Brian Williams; Rob Wolfs; Michael Wright; Shinya Yamada; Hiroya Yamaguchi; Kazutaka Yamaoka; Noriko Yamasaki; Shigeo Yamauchi; Makoto Yamauchi; Keiichi Yanagase; Tahir Yaqoob; Susumu Yasuda; Nasa Yoshioka; Jaime Zabala; Irina Zhuravleva, The ASTRO-H mission was designed and developed through an international collaboration of JAXA, NASA, ESA, and the CSA. It was successfully launched on February 17, 2016, and then named Hitomi. During the in-orbit verification phase, the on-board observational instruments functioned as expected. The intricate coolant and refrigeration systems for soft X-ray spectrometer (SXS, a quantum micro-calorimeter) and soft X-ray imager (SXI, an X-ray CCD) also functioned as expected. However, on March 26, 2016, operations were prematurely terminated by a series of abnormal events and mishaps triggered by the attitude control system. These errors led to a fatal event: the loss of the solar panels on the Hitomi mission. The X-ray Astronomy Recovery Mission (or, XARM) is proposed to regain the key scientific advances anticipated by the international collaboration behind Hitomi. XARM will recover this science in the shortest time possible by focusing on one of the main science goals of Hitomi, "Resolving astrophysical problems by precise high-resolution X-ray spectroscopy".(1) This decision was reached after evaluating the performance of the instruments aboard Hitomi and the mission's initial scientific results, and considering the landscape of planned international X-ray astrophysics missions in 2020's and 2030's.Hitomi opened the door to high-resolution spectroscopy in the X-ray universe. It revealed a number of discrepancies between new observational results and prior theoretical predictions. Yet, the resolution pioneered by Hitomi is also the key to answering these and other fundamental questions. The high spectral resolution realized by XARM will not offer mere refinements; rather, it will enable qualitative leaps in astrophysics and plasma physics. XARM has therefore been given a broad scientific charge: "Revealing material circulation and energy transfer in cosmic plasmas and elucidating evolution of cosmic structures and objects". To fulfill this charge, four categories of science objectives that were defined for Hitomi will also be pursued by XARM; these include (1) Structure formation of the Universe and evolution of clusters of galaxies; (2) Circulation history of baryonic matters in the Universe; (3) Transport and circulation of energy in the Universe; (4) New science with unprecedented high resolution X-ray spectroscopy. In order to achieve these scientific objectives, XARM will carry a 6 x 6 pixelized X-ray micro-calorimeter on the focal plane of an X-ray mirror assembly, and an aligned X-ray CCD camera covering the same energy band and a wider field of view. This paper introduces the science objectives, mission concept, and observing plan of XARM., 2018, 10699, id.1069922, 10.1117/12.2309455

Not Refereed, 教育システム研究別冊「本学の教員養成課程の改善・高度化に向けた大学教員と附属教員の連携研究 推進事業」成果論文集, 中学校理科におけるモーターの製作を取り入れた「電流が磁場から受ける力」の学習の実践と検討, YAMAUCHI Shigeo, Oct. 2017, 101-105

Not Refereed, 教育システム研究別冊「本学の教員養成課程の改善・高度化に向けた大学教員と附属教員の連携研究 推進事業」成果論文集, 高等学校「地学基礎」における二重フーリエ級数を用いた地質図の見方および地質断面図の作成の実 践と検討, YAMAUCHI Shigeo, Oct. 2017, 161-164

Not Refereed, Proceedings of 35th ICRC, First discovery of iron line emission generated by low-energy cosmic rays, YAMAUCHI Shigeo; Nobukawa; K. K; Nobukawa, M; Yamauchi, S; Uchiyama, H; Koyama, K, Jul. 2017, 687

Not Refereed, Proceedings of the XII Multifrequency Behaviour of High Energy Cosmic Sources Workshop, Origin of the Galactic Diffuse X-Ray Emission: Fe Line Diagnostics with Suzaku, YAMAUCHI Shigeo; Nobukawa, M; Nobukawa, K. K; Yamauchi, S; Uchiyama, H; Koyama, K, Jun. 2017, 55

Not Refereed, 日本天文学会年会講演予稿集, 銀河リッジX線放射の中性鉄輝線における宇宙線の寄与, 信川久実子; 山内茂雄; 信川正順; 鶴剛; 小山勝二; 鳥居和史; 福井康雄, 20 Feb. 2016, 2016, 116

Not Refereed, Proceedings of SPIE - The International Society for Optical Engineering, Performance of ASTRO-H hard X-ray telescope (HXT), Hisamitsu Awaki; Hideyo Kunieda; Manabu Ishida; Hironori Matsumoto; Akihiro Furuzawa; Yoshito Haba; Takayuki Hayashi; Ryo Iizuka; Kazunori Ishibashi; Masayuki Itoh; Tatsuro Kosaka; Yoshitomo Maeda; Ikuyuki Mitsuishi; Takuya Miyazawa; Hideyuki Mori; Hosei Nagano; Yoshiharu Namba; Yasushi Ogasaka; Keiji Ogi; Takashi Okajima; Satoshi Sugita; Yoshio Suzuki; Keisuke Tamura; Yuzuru Tawara; Kentaro Uesugi; Shigeo Yamauchi, © 2016 SPIE. The Japanese X-ray Astronomy Satellite, Hitomi (ASTRO-H) carries hard X-ray imaging system, covering the energy band from 5 keV to 80 keV. The hard X-ray imaging system consists of two hard X-ray telescopes (HXT) and the focal plane detectors (HXI). The HXT employs tightly-nested, conically-approximated thin foil Wolter-I optics. The mirror surfaces of HXT were coated with Pt/C depth-graded multilayers. We carried out ground calibrations of HXTs at the synchrotron radiation facility SPring-8/BL20B2 Japan, and found that total effective area of two HXTs was about 350 cm2 at 30 keV, and the half power diameter of HXT was about 1.'9. After the launch of Hitomi, Hitomi observed several targets during the initial functional verification of the onboard instruments. The Hitomi software and calibration team (SCT) provided the Hitomi's data of G21.5-0.9, a pulsar wind nebula, to the hardware team for the purpose of the instrument calibration. Through the analysis of the in-flight data, we have confirmed that the X-ray performance of HXTs in orbit was consistent with that obtained by the ground calibrations., 2016, 9905, id.990512, 10.1117/12.2231258

Not Refereed, Proceedings of SPIE - The International Society for Optical Engineering, The ASTRO-H (Hitomi) X-ray astronomy satellite, Tadayuki Takahashi; Motohide Kokubun; Kazuhisa Mitsuda; Richard Kelley; Takaya Ohashi; Felix Aharonian; Hiroki Akamatsu; Fumie Akimoto; Steve Allen; Naohisa Anabuki; Lorella Angelini; Keith Arnaud; Makoto Asai; Marc Audard; Hisamitsu Awaki; Magnus Axelsson; Philipp Azzarello; Chris Baluta; Aya Bamba; Nobutaka Bando; Marshall Bautz; Thomas Bialas; Roger Blandford; Kevin Boyce; Laura Brenneman; Greg Brown; Esra Bulbul; Edward Cackett; Edgar Canavan; Maria Chernyakova; Meng Chiao; Paolo Coppi; Elisa Costantini; Jelle De Plaa; Jan Willem Den Herder; Michael DiPirro; Chris Done; Tadayasu Dotani; John Doty; Ken Ebisawa; Megan Eckart; Teruaki Enoto; Yuichiro Ezoe; Andrew Fabian; Carlo Ferrigno; Adam Foster; Ryuichi Fujimoto; Yasushi Fukazawa; Akihiro Furuzawa; Massimiliano Galeazzi; Luigi Gallo; Poshak Gandhi; Kirk Gilmore; Margherita Giustini; Andrea Goldwurm; Liyi Gu; Matteo Guainazzi; Daniel Haas; Yoshito Haba; Kouichi Hagino; Kenji Hamaguchi; Atsushi Harayama; Ilana Harrus; Isamu Hatsukade; Takayuki Hayashi; Katsuhiro Hayashi; Kiyoshi Hayashida; Junko Hiraga; Kazuyuki Hirose; Ann Hornschemeier; Akio Hoshino; John Hughes; Yuto Ichinohe; Ryo Iizuka; Yoshiyuki Inoue; Hajime Inoue; Kazunori Ishibashi; Manabu Ishida; Kumi Ishikawa; Kosei Ishimura; Yoshitaka Ishisaki; Masayuki Itoh; Naoko Iwata; Naoko Iyomoto; Chris Jewell; Jelle Kaastra; Timothy Kallman; Tuneyoshi Kamae; Erin Kara; Jun Kataoka; Satoru Katsuda; Junichiro Katsuta; Madoka Kawaharada; Nobuyuki Kawai; Taro Kawano; Shigeo Kawasaki; Dmitry Khangulyan; Caroline Kilbourne; Mark Kimball; Ashley King, © 2016 SPIE. The Hitomi (ASTRO-H) mission is the sixth Japanese X-ray astronomy satellite developed by a large international collaboration, including Japan, USA, Canada, and Europe. The mission aimed to provide the highest energy resolution ever achieved at E > 2 keV, using a microcalorimeter instrument, and to cover a wide energy range spanning four decades in energy from soft X-rays to gamma-rays. After a successful launch on 2016 February 17, the spacecraft lost its function on 2016 March 26, but the commissioning phase for about a month provided valuable information on the on-board instruments and the spacecraft system, including astrophysical results obtained from first light observations. The paper describes the Hitomi (ASTRO-H) mission, its capabilities, the initial operation, and the instruments/spacecraft performances confirmed during the commissioning operations for about a month., 2016, 9905, id.99050U, 10.1117/12.2232379

Not Refereed, Proceedings of SPIE - The International Society for Optical Engineering, Ray-tracing simulation and in-orbit performance of the ASTRO-H hard X-ray telescope (HXT), H. Matsumoto; H. Awaki; A. Furuzawa; M. Ishida; H. Kunieda; Y. Haba; T. Hayashi; R. Iizuka; K. Ishibashi; M. Itoh; T. Kosaka; Y. Maeda; I. Mitsuishi; T. Miyazawa; H. Mori; H. Nagano; Y. Namba; Y. Ogasaka; K. Ogi; T. Okajima; S. Sugita; Y. Suzuki; K. Tamura; Y. Tawara; K. Uesugi; S. Yamauchi, © 2016 SPIE. A ray-trace simulation code for the Hard X-ray Telescope (HXT) on board the Hitomi (ASTRO-H) satellite is being developed. The half power diameter and effective area simulated based on the code are consistent with ground measurements within 10%. The HXT observed the pulsar wind nebula G21.5-0.9 for 105 ksec. We confirmed that the encircled energy function and the half power diameter obtained from the data are consistent with the ground measurements., 2016, 9905, id.990541, 10.1117/12.2232135

Not Refereed, Proceedings of the International Astronomical Union, Cambridge University Press, Origin of the galactic diffuse X-ray emission: Iron K-shell line diagnostics, Masayoshi Nobukawa; Hideki Uchiyama; Kumiko K. Nobukawa; Shigeo Yamauchi; Katsuji Koyama, An unresolved X-ray emission extends along the Galactic plane, so-called the Galactic diffuse X-ray emission (GDXE). The characteristic feature is three K-shell lines of Fe at 6.4, 6.7, and 6.9 keV. Recently, superposition of faint point sources, such as Cataclysmic variables (CVs) and Active binaries (ABs) is thought to be a major origin, although it is under debate which sub-class mostly contribute. We re-analyzed the Suzaku archive data and constructed spectral models of ABs, magnetic CVs (mCVs), and non-magnetic CVs (non-mCVs). The GBXE is explained by combination of those models non-mCVs and ABs mainly contribute while mCVs account for ∼10% or less of the 5-10 keV flux. On the other hand, the GCXE and GRXE spectra cannot be represented by any combination of the point sources, indicating another origin would be required., 2016, 11, 206, 207, 10.1017/S1743921316012102

Not Refereed, 日本天文学会年会講演予稿集, 銀河リッジX線放射の6.4keV輝線, 信川久実子; 信川正順; 鶴剛; 小山勝二; 山内茂雄, 20 Aug. 2015, 2015, 167

Not Refereed, Proceedings of the conference Suzaku-MAXI 2014: ”Expanding the Frontiers of the X-ray Universe”, Mixed-morphology supernova remnant Kes27 with Suzaku, YAMAUCHI Shigeo; Minami, S; Yamauchi, S; Koyama, K, Sep. 2014, 48-49

Not Refereed, Proceedings of the conference Suzaku-MAXI 2014: ”Expanding the Frontiers of the X-ray Universe”, A Suzaku comprehensive study of recombining plasma in SNRs, YAMAUCHI Shigeo; Sawada; M; Koyama, K; Bamba, A; Yamauchi, S; Fukui, Y, Sep. 2014, 64-65

Not Refereed, Proceedings of the conference Suzaku-MAXI 2014: ”Expanding the Frontiers of the X-ray Universe”, Suzaku Observation of the Spiral Galaxy M101, YAMAUCHI Shigeo, Sep. 2014, 420-421

Not Refereed, Proceedings of SPIE - The International Society for Optical Engineering, The ASTRO-H X-ray astronomy satellite, Tadayuki Takahashi; Kazuhisa Mitsuda; Richard Kelley; Felix Aharonian; Hiroki Akamatsu; Fumie Akimoto; Steve Allen; Naohisa Anabuki; Lorella Angelini; Keith Arnaud; Makoto Asai; Marc Audard; Hisamitsu Awaki; Philipp Azzarello; Chris Baluta; Aya Bamba; Nobutaka Bando; Marshall Bautz; Thomas Bialas; Roger D. Blandford; Kevin Boyce; Laura Brenneman; Gregory Brown; Ed Cackett; Edgar Canavan; Maria Chernyakova; Meng Chiao; Paolo Coppi; Elisa Costantini; Jelle De Plaa; Jan Willem Den Herder; Michael Dipirro; Chris Done; Tadayasu Dotani; John Doty; Ken Ebisawa; Teruaki Enoto; Yuichiro Ezoe; Andrew Fabian; Carlo Ferrigno; Adam Foster; Ryuichi Fujimoto; Yasushi Fukazawa; Stefan Funk; Akihiro Furuzawa; Massimiliano Galeazzi; Luigi Gallo; Poshak Gandhi; Kirk Gilmore; Matteo Guainazzi; Daniel Haas; Yoshito Haba; Kenji Hamaguchi; Atsushi Harayama; Isamu Hatsukade; Katsuhiro Hayashi; Takayuki Hayashi; Kiyoshi Hayashida; Junko Hiraga; Kazuyuki Hirose; Ann Hornschemeier; Akio Hoshino; John Hughes; Una Hwang; Ryo Iizuka; Yoshiyuki Inoue; Kazunori Ishibashi; Manabu Ishida; Kumi Ishikawa; Kosei Ishimura; Yoshitaka Ishisaki; Masayuki Itoh; Naoko Iwata; Naoko Iyomoto; Chris Jewell; Jelle Kaastra; Timothy Kallman; Tuneyoshi Kamae; Jun Kataoka; Satoru Katsuda; Junichiro Katsuta; Madoka Kawaharada; Nobuyuki Kawai; Taro Kawano; Shigeo Kawasaki; Dmitry Khangaluyan; Caroline Kilbourne; Mark Kimball; Masashi Kimura; Shunji Kitamoto; Tetsu Kitayama; Takayoshi Kohmura; Motohide Kokubun; Saori Konami; Tatsuro Kosaka; Alexander Koujelev; Katsuji Koyama; Hans Krimm; Aya Kubota; Hideyo Kunieda, © 2014 SPIE. The joint JAXA/NASA ASTRO-H mission is the sixth in a series of highly successful X-ray missions developed by the Institute of Space and Astronautical Science (ISAS), with a planned launch in 2015. The ASTRO-H mission is equipped with a suite of sensitive instruments with the highest energy resolution ever achieved at E > 3 keV and a wide energy range spanning four decades in energy from soft X-rays to gamma-rays. The simultaneous broad band pass, coupled with the high spectral resolution of ΔE ≤ 7 eV of the micro-calorimeter, will enable a wide variety of important science themes to be pursued. ASTRO-H is expected to provide breakthrough results in scientific areas as diverse as the large-scale structure of the Universe and its evolution, the behavior of matter in the gravitational strong field regime, the physical conditions in sites of cosmic-ray acceleration, and the distribution of dark matter in galaxy clusters at different redshifts., 2014, 9144, id.914425, 10.1117/12.2055681

Not Refereed, Proceedings of SPIE - The International Society for Optical Engineering, ASTRO-H Hard X-ray Telescope (HXT), Hisamitsu Awaki; Hideyo Kunieda; Akihiro Furuzawa; Yoshito Haba; Takayuki Hayashi; Ryo Iizuka; Kazunori Ishibashi; Manabu Ishida; Masayuki Itoh; Tatsuro Kosaka; Yoshitomo Maeda; Hironori Matsumoto; Takuya Miyazawa; Hideyuki Mori; Hosei Nagano; Yoshiharu Namba; Yasushi Ogasaka; Keiji Ogi; Takashi Okajima; Satoshi Sugita; Yoshio Suzuki; Keisuke Tamura; Yuzuru Tawara; Kentaro Uesugi; Koujun Yamashita; Shigeo Yamauchi, © 2014 SPIE. The new Japanese X-ray Astronomy satellite, ASTRO-H will carry two identical hard X-ray telescopes (HXTs), which cover 5 to 80 keV, in order to provide new insights into frontier of X-ray astronomy. The HXT mirror surfaces are coated with Pt/C depth-graded multilayers to enhance hard X-ray effective area by means of Bragg reflection, and 213 mirror reflectors with a thickness of 0.22 mm are tightly nested confocally in a telescope. The production of FM HXT-1 and HXT-2 were completed in 2012 and 2013, respectively. The X-ray performance of HXTs were measured at the synchrotron radiation facility SPring-8/ BL20B2 Japan. The total effective area of two HXTs is about 350 cm2 at 30 keV and the angular resolution of HXT is about 1.'9 in half power diameter at 30 keV. The HXTs are in the clean room at ISAS for waiting the final integration test., 2014, 9144, id.914426, 10.1117/12.2054633

Not Refereed, Proceedings of SPIE - The International Society for Optical Engineering, The ASTRO-H X-ray observatory, Tadayuki Takahashi; Kazuhisa Mitsuda; Richard Kelley; Henri Aarts; Felix Aharonian; Hiroki Akamatsu; Fumie Akimotoe; Steve Allen; Naohisa Anabuki; Lorella Angelini; Keith Arnaud; Makoto Asai; Marc Audard; Hisamitsu Awaki; Philipp Azzarello; Chris Baluta; Aya Bamba; Nobutaka Bando; Mark Bautz; Roger Blandford; Kevin Boyce; Greg Brown; Ed Cackett; Maria Chernyakova; Paolo Coppi; Elisa Costantini; Jelle De Plaa; Jan Willem Den Herder; Michael DiPirro; Chris Done; Tadayasu Dotani; John Doty; Ken Ebisawa; Megan Eckart; Teruaki Enoto; Yuichiro Ezoe; Andrew Fabian; Carlo Ferrigno; Adam Foster; Ryuichi Fujimoto; Yasushi Fukazawa; Stefan Funk; Akihiro Furuzawa; Massimiliano Galeazzi; Luigi Gallo; Poshak Gandhi; Keith Gendreau; Kirk Gilmore; Daniel Haas; Yoshito Haba; Kenji Hamaguchi; Isamu Hatsukade; Takayuki Hayashi; Kiyoshi Hayashida; Junko Hiraga; Kazuyuki Hirose; Ann Hornschemeier; Akio Hoshino; John Hughes; Una Hwang; Ryo Iizuka; Yoshiyuki Inoue; Kazunori Ishibashi; Manabu Ishida; Kosei Ishimura; Yoshitaka Ishisaki; Masayuki Ito; Naoko Iwat; Naoko Iyomoto; Jelle Kaastr; Timothy Kallman; Tuneyoshi Kamae; Jun Kataoka; Satoru Katsuda; Hajime Kawahara; Madoka Kawaharada; Nobuyuki Kawai; Shigeo Kawasaki; Dmitry Khangaluyan; Caroline Kilbourne; Masashi Kimura; Kenzo Kinugasaa; Shunji Kitamoto; Tetsu Kitayama; Takayoshi Kohmura; Motohide Kokubun; Tatsuro Kosaka; Alex Koujelev; Katsuji Koyama; Hans Krimm; Aya Kubota; Hideyo Kunieda; Stephanie LaMass; Philippe Laurent; Francois Lebrun; Maurice Leutenegger; Olivier Limousin; Michael Loewenstein; Knox Long; David Lumb, The joint JAXA/NASA ASTRO-H mission is the sixth in a series of highly successful X-ray missions initiated by the Institute of Space and Astronautical Science (ISAS). ASTRO-H will investigate the physics of the highenergy universe via a suite of four instruments, covering a very wide energy range, from 0.3 keV to 600 keV. These instruments include a high-resolution, high-Throughput spectrometer sensitive over 0.3-12 keV with high spectral resolution of ?E 5 7 eV, enabled by a micro-calorimeter array located in the focal plane of thin-foil X-ray optics; hard X-ray imaging spectrometers covering 5-80 keV, located in the focal plane of multilayer-coated, focusing hard X-ray mirrors; a wide-field imaging spectrometer sensitive over 0.4-12 keV, with an X-ray CCD camera in the focal plane of a soft X-ray telescope; and a non-focusing Compton-camera type soft gamma-ray detector, sensitive in the 40-600 keV band. The simultaneous broad bandpass, coupled with high spectral resolution, will enable the pursuit of a wide variety of important science themes. © 2012 SPIE., 2012, 8443, id.84431Z-84431Z-22, 10.1117/12.926190

Not Refereed, Proceedings of SPIE - The International Society for Optical Engineering, Current status of ASTRO-H Hard X-ray telescopes (HXTs), Hisamitsu Awaka; Hideyo Kunieda; Akihiro Furuzawa; Yoshito Haba; Takayuki Hayashi; Ryo Iizuka; Kazunori Ishibashi; Manabu Ishida; Masayuki Itoh; Tatsuro Kosaka; Yoshitomo Maeda; Hironori Matsumoto; Takuya Miyazawa; Hideyuki Mori; Hosei Nagano; Yoshiharu Namba; Yasushi Ogasaka; Keiji Ogi; Takashi Okajima; Satoshi Sugita; Yoshio Suzuki; Keisuke Tamura; Yuzuru Tawara; Kentato Uesugi; Koujun Yamashita; Shigeo Yamauchi, ASTRO-H is an international X-ray mission of ISAS/JAXA, which will be launched in 2014. One of the main characteristics of ASTRO-H is imaging spectroscopy in the hard X-ray band above 10 keV. ASTRO-H will carry two identical Hard X-ray telescopes (HXTs), whose mirror surfaces are coated with Pt/C depth-graded multilayers to enhance hard X-ray effective area up to 80 keV. HXT was designed based on the telescope on board the SUMIT balloon borne experiment. After feasibility study of the HXT design, the FM design has been deteremined. Mass production of the mirror shells at Nagoya University has been going on since August 2010, and production of mirror shells for HXT-1 was completed in March 2012. After the integation of X-ray mirrors for HXT-1, we measured hard X-ray performance of selected mirror shells for HXT-1 at a synchrotron radiation facility, SPring-8 beamline BL20B2. We will perform environment tests and ground calibarations at SPring-8 for HXT-1. In HXT-2, foil production is going on. © 2012 SPIE., 2012, 8443, id.844324-844324-8, 10.1117/12.926753

Not Refereed, Proceedings of the 3rd Suzaku conference ”The Energetic Cosmos: from Suzaku to Astro-H”, Japan Aerospace Exploration Agency (JAXA), X-Ray Re?ection Nebulae with Large Equivalent Widths of Neutral Iron K-alpha Line in the Sgr C Region, YAMAUCHI Shigeo; Naka jima, H; Tsuru, T; Nobukawa, M; Matsumoto, H; Koyama, K; Murakami, H; Yamauchi, S, The 3rd Suzaku international Conference "Energetic Cosmos : from Suzaku to ASTRO-H" (June 29-July 2, 2009. Grand Park Otaru Hotel), Otaru, Hokkaido JapanWe report on the results of the Suzaku observation in the Sgr C region, vicinity of the Galactic Center where there are giant MCs. We detected four diffuse clumps with strong line emission at 6.4 keV, Kalpha from neutral or low-ionized Fe. The X-ray spectra of the two bright clumps, exhibit strong Kalpha line from FeI with large equivalent widths (EWs) of 2.0 - 2.2 keV and clear Kbeta of FeI. The GCDX in the Sgr C region is composed of the 6.4 keV- and 6.7 keV-associated components. These are phenomenologically decomposed by taking relations between EWs of the 6.4 keV and 6.7 keV lines. Then the former EWs against the associated continuum in the bright clump regions are estimated to be 2.4(sup +2.3)(sub -0.7) keV. Since the two different approaches give similar large EWs of 2 keV, we strongly suggest that the 6.4 keV clumps in the Sgr C region are due to X-ray reflection/fluorescence (the X-ray reflection nebulae).Meeting sponsors: The University of Tokyo, The Institute of Physical and Chemical Research, The Japan Society for the Promotion of Science, 2010, 9, 114-115, 115

Not Refereed, Proceedings of the 3rd Suzaku conference ”The Energetic Cosmos: from Suzaku to Astro-H”, Suzaku Observation of the Supernova Remnant G344.7-0.1, YAMAUCHI Shigeo, 2010, 122-123

Not Refereed, Proceedings of the 3rd Suzaku conference ”The Energetic Cosmos: from Suzaku to Astro-H”, Characteristics of Energy Spectrum of the Galactic Ridge X-Ray Emission, YAMAUCHI Shigeo; Tanaka, Y; Yamauchi, S, 2010, 146-149

Not Refereed, Proceedings of the 3rd Suzaku conference ”The Energetic Cosmos: from Suzaku to Astro-H”, Suzaku Spectroscopy of a Magnetar 1E 1841-045 and Search for NIR Pulsation of a Magnetar 4U 0142+61, YAMAUCHI Shigeo; Morii, M; Kawai, N; Terada, Y; Takahashi, H; Arimoto, M; Kitamoto, S; Kohmura, T; Shibazaki, N; Yamauchi, S; Kobayashi, N; Tanaka, Y. T; Terada, H, 2010, 218-219

Not Refereed, Proceedings of SPIE - The International Society for Optical Engineering, The ASTRO-H mission, Tadayuki Takahashi; Kazuhisa Mitsuda; Richard Kelley; Felix Aharonian; Fumie Akimoto; Steve Allen; Naohisa Anabuki; Lorella Angelini; Keith Arnaud; Hisamitsu Awaki; Aya Bamba; Nobutaka Bando; Mark Bautz; Roger Blandford; Kevin Boyce; Greg Brown; Maria Chernyakova; Paolo Coppi; Elisa Costantini; Jean Cottam; John Crow; Jelle De Plaa; Cor De Vries; Jan Willem Den Herder; Michael DiPirro; Chris Done; Tadayasu Dotani; Ken Ebisawa; Teruaki Enoto; Yuichiro Ezoe; Andrew Fabian; Ryuichi Fujimoto; Yasushi Fukazawa; Stefan Funk; Akihiro Furuzawa; Massimiliano Galeazzi; Poshak Gandhi; Keith Gendreau; Kirk Gilmore; Yoshito Haba; Kenji Hamaguchi; Isamu Hatsukade; Kiyoshi Hayashida; Junko Hiraga; Kazuyuki Hirose; Ann Hornschemeier; John Hughes; Una Hwang; Ryo Iizuka; Kazunori Ishibashi; Manabu Ishida; Kosei Ishimura; Yoshitaka Ishisaki; Naoki Isobe; Masayuki Ito; Naoko Iwata; Jelle Kaastra; Timothy Kallman; Tuneyoshi Kamae; Hideaki Katagiri; Jun Kataoka; Satoru Katsuda; Madoka Kawaharada; Nobuyuki Kawai; Shigeo Kawasaki; Dmitry Khangaluyan; Caroline Kilbourne; Kenzo Kinugasa; Shunji Kitamoto; Tetsu Kitayama; Takayoshi Kohmura; Motohide Kokubun; Tatsuro Kosaka; Taro Kotani; Katsuji Koyama; Aya Kubota; Hideyo Kunieda; Philippe Laurent; François Lebrun; Olivier Limousin; Michael Loewenstein; Knox Long; Grzegorz Madejski; Yoshitomo Maeda; Kazuo Makishima; Maxim Markevitch; Hironori Matsumoto; Kyoko Matsushita; Dan McCammon; Jon Miller; Shin Mineshige; Kenji Minesugi; Takuya Miyazawa; Tsunefumi Mizuno; Koji Mori; Hideyuki Mori; Koji Mukai; Hiroshi Murakami; Toshio Murakami; Richard Mushotzky, © 2010 SPIE. The joint JAXA/NASA ASTRO-H mission is the sixth in a series of highly successful X-ray missions initiated by the Institute of Space and Astronautical Science (ISAS). ASTRO-H will investigate the physics of the high-energy universe by performing high-resolution, high-throughput spectroscopy with moderate angular resolution. ASTRO-H covers very wide energy range from 0.3 keV to 600 keV. ASTRO-H allows a combination of wide band X-ray spectroscopy (5-80 keV) provided by multilayer coating, focusing hard X-ray mirrors and hard X-ray imaging detectors, and high energy-resolution soft X-ray spectroscopy (0.3-12 keV) provided by thin-foil X-ray optics and a micro-calorimeter array. The mission will also carry an X-ray CCD camera as a focal plane detector for a soft X-ray telescope (0.4-12 keV) and a non-focusing soft gamma-ray detector (40-600 keV). The micro-calorimeter system is developed by an international collaboration led by ISAS/JAXA and NASA. The simultaneous broad bandpass, coupled with high spectral resolution of ΔE ~7 eV provided by the micro-calorimeter will enable a wide variety of important science themes to be pursued., 2010, 7732, 77320Z-77320Z-18, 10.1117/12.857875

Not Refereed, Proceedings of SPIE - The International Society for Optical Engineering, Hard X-ray telescope to be onboard ASTRO-H, Hideyo Kunieda; Hisamitsu Awaki; Akihiro Furuzawa; Yoshito Haba; Ryo Iizuka; Kazunori Ishibashi; Manabu Ishida; Masayuki Itoh; Tatsuro Kosaka; Yoshitomo Maeda; Hironori Matsumoto; Takuya Miyazawa; Hideyuki Mori; Yoshiharu Namba; Yasushi Ogasaka; Keiji Ogi; Takashi Okajima; Yoshio Suzuki; Keisuke Tamura; Yuzuru Tawara; Kentato Uesugi; Koujun Yamashita; Shigeo Yamauchi, The new Japanese X-ray Astronomy satellite, ASTRO-H will carry two identical hard X-ray telescopes (HXTs), which cover 5 to 80 keV. The HXT mirrors employ tightly-nested, conically-approximated thin-foil Wolter-I optics, and the mirror surfaces are coated with Pt/C depth-graded multilayers to enhance hard X-ray effective area by means of Bragg reflection. The HXT comprises foils 450 mm in diamter and 200 mm in length, with a focal length of 12 m. To obtain a large effective area, 213 aluminum foils 0.2 mm in thickness are tightly nested confocally. The effective area is expected to be ∼ 310 cm2 at 30 keV and the image quality to be ∼1.7′ in half-power diameter. © 2010 SPIE., 2010, 7732, 773214-773214-12, 10.1117/12.856892

Not Refereed, SPACE TELESCOPES AND INSTRUMENTATION 2010: ULTRAVIOLET TO GAMMA RAY, SPIE-INT SOC OPTICAL ENGINEERING, Current Status of the Pre-Collimator Development for the ASTRO-H X-ray Telescopes, Hideyuki Mori; Yoshito Haba; Takuya Miyazawa; Akihiro Furuzawa; Yuzuru Tawara; Hideyo Kunieda; Shigeo Yamauchi; Hisamitsu Awaki; Manabu Ishida; Yoshitomo Maeda; Aya Bamba; Ryo Iizuka; Takashi Okajima; Richard Mushotzky, We present the current status of the pre-collimator for the stray-light reduction, mounted on the ASTRO-H X-Ray Telescopes (XRT). Since the ASTRO-H XRTs adopt the conical approximation of the Wolter-I type grazing incident optics, X-rays from a source located far from the telescope boresight create a ghost image in the detector field of view (FOV) as a stray light, and then reduce the signal-to-noise ratio even in the hard X-ray band. We thus plan to mount the pre-collimator, which is comprised of cylindrical blades aligned with each primary mirror, onto the XRTs to remove the stray light. While the pre-collimator for the Soft X-ray Telescopes is designed by the similar principle adopted for the Suzaku pre-collimator, that for the Hard X-ray Telescopes requires some trade-off studies to select an appropriate blade material. The HXT pre-collimator currently utilizes the aluminum blade with the 50 mm height and 150 mu m thickness. We examined the observational effects by the hard X-ray (> 10 keV) stray light and the expected performance of the pre-collimator in some scientific cases, using a ray-tracing simulator. We found that the Galactic center may be mostly covered with the stray light from the well-known bright X-ray sources. In addition, the flux estimation of the extended X-ray emission such as the Cosmic X-ray Background is also found to have large (similar to 30%) uncertainty due to the stray light from the outside of the XRT FOV. The pre-collimator improves the situations; the stray light covering the source-free region in the Galactic center can be reduced by half and the uncertainty of the flux determination for the diffuse source decreases down to < 10%., 2010, 7732, 77323E-77323E-10, 10.1117/12.856803

Not Refereed, Proceedings of the 4th international MAXI workshop ”The First Year of MAXI: Monitoring Variable X-Ray sources”, Ginga Observation of a Recurrent Soft X-Ray Transient Source 1RXS J170930.2-263927, YAMAUCHI Shigeo, 2010, 193-196

Not Refereed, Meeting abstracts of the Physical Society of Japan, 一般社団法人日本物理学会, 22aZJ-9 Suzaku Observation of Extended Hard X-ray Emission of the Galactic Center, Nakazawa K; Kokubun M; Makishima K; Takahashi T; Ebisawa K; Bamba A; Senda A; Mori H; Inui T; Hyodo Y; Uchiyama H; Takikawa Y; Nobukawa M; Matsumoto H; Tsuru T; Koyama K; Yamauchi S; Takahashi H; Mizuno T, 21 Aug. 2007, 62, 2, 107, 107

Not Refereed, PROGRESS OF THEORETICAL PHYSICS SUPPLEMENT, PROGRESS THEORETICAL PHYSICS PUBLICATION OFFICE, Hard X-ray investigation of the galactic center region with Suzaku, Motohide Kokubun; Takayuki Yuasa; Ken-ichi Tamura; Kazuo Makishima; Tadayuki Takahashi; Kazuhiro Nakazawa; Noriko Y. Yamasaki; Hiroshi Murakami; Yoshitomo Maeda; Ken Ebisawa; Katsuji Koyama; Shigeo Yamauchi; Yasushi Fukazawa; Tsunefumi Mizuno; Hiromitsu Takahashi; Aya Bamba; Atsushi Senda; Yasuo Tanaka; Tsuneyoshi Kamae, The Galactic center (GC) region has been known to exhibit strong enhancements of hot diffuse plasma, which is characterized by the highly ionized Fe-K fluorescence line. Based on past X-ray observations with Ginga, ASCA, and RXTE, in the Galactic plane or bulge region, a non-thermal emission, so-called the "hard-tail", has been confirmed to dominate the hard X-ray flux above 10 keV, and an association was found between surface brightnesses of the thermal and non-thermal components despite the completely different emission mechanism. Therefore, it is obviously important to investigate an existence of the hard-tail at GC with the unprecedented sensitivity of the HXD onboard Suzaku. By combining its narrow field-of-view of 30' and X-ray images simultaneously obtained by the XIS below 10 keV, an extensive investigation of spectral and spatial properties of the GC hard X-ray emission can be for the first time realized. We will report on results from seven pointings around GC, with a total exposure of 300 ks, performed in the performance verification phase of Suzaku. Strong hard X-ray signals were clearly detected in every observation by HXD-PIN in 10-70 keV range with a few tenth mCrab level intensities., 2007, 169, 169, 109, 112

Not Refereed, PROGRESS OF THEORETICAL PHYSICS SUPPLEMENT, PROGRESS THEORETICAL PHYSICS PUBLICATION OFFICE, Suzaku spectral study of the galactic ridge X-ray emission, Ken Ebisawa; Shigeo Yamauchi; Yasuo Tanaka; Katsuji Koyama, We have observed a typical Galactic plane blank field with Suzaku for 100 ksec to carry out spectral study of the Galactic Ridge X-ray Emission (GRXE). The field had been previously studied with Chandra, and is known to be devoid of bright X-ray point sources. We were able to resolve, for the first time, three narrow iron K-emission lines from low-ionized (6.4 keV), helium-like (6.67 keV), and hydrogenic ions (7.0 keV). These line features constrain the GRXE emission mechanisms. The cosmic-ray ion charge exchange model or the non-ionization equirribrium (NIE) plasma model are very unlikely, since they require either broad emission lines or lines at intermediate ionization states. We were able to precisely measure the absolute GRXE flux thanks to the low background and small stray-light contamination of Suzaku. Excluding point sources brighter than 2 x 10(-13) ergs s(-1) cm(-2) (2-10 keV), only similar to 10% of the 2-10 keV GRXE flux is explained by the Chandra point sources brighter than 3 x 10(-15) ergs s(-1) cm(-2)., 2007, 169, 169, 121, 124

Not Refereed, 40 YEARS OF PULSARS: MILLISECOND PULSARS, MAGNETARS AND MORE, AMER INST PHYSICS, Suzaku observation of AXP 1E 1841-045 in SNR Kes 73, M. Morii; S. Kitatnoto; N. Shibazaki; D. Takei; N. Kawai; M. Arimotot; M. Ueno; Y. Terada; T. Kohmura; S. Yamauchi, Anomalous X-ray pulsars (AXPs) are thought to be magnetars, which are neutron stars with ultra strong magnetic field of 10(14)-10(15) G. Their energy spectra below similar to 10 keV are modeled well by two components consisting of a blackbody (BB) (similar to 0.4 keV) and rather steep power-law (POW) function (photon index similar to 2-4). Kuiper et al.(2004) discovered hard X-ray component above similar to 10 keV from some AXPs. Here, we present the Suzaku observation of the AXP 1E 1841-045 at the center of supernova remnant Kes 73. By this observation, we could analyze the spectrum from 0.4 to 50 keV at the same time. Then, we could test whether the spectral model above was valid or not in this wide energy range. We found that there were residual in the spectral fits when fit by the model of BB + POW. Fits were improved by adding another BB or POW component. But the meaning of each component became ambiguous in the phase-resolved spectroscopy. Alternatively we found that NPEX model fit well for both phase-averaged spectrum and phase-resolved spectra. In this case, the photon indices were constant during all phase, and spectral variation seemed to be very clear. This fact suggests somewhat fundamental meaning for the emission from magnetars., 2007, 983, 268, +

Not Refereed, 日本物理学会講演概要集, 一般社団法人 日本物理学会, 23pSH-7 「すざく」によるHESS未同定天体HESS J1804-216の観測(23pSH X線・γ線,宇宙線・宇宙物理領), 馬場 彩; 高橋 忠幸; 坪井 陽子; 山内 茂雄; 湯浅 孝行; 「すざく」HXDチーム; 小山 勝二; 平賀 純子; Hughes J.P; 幸村 孝由; 国分 紀秀; 前田 良知; 松本 浩典; 千田 篤史, 2006, 61, 0, 77, 77

Not Refereed, Proceedings of the International Astronomical Union, Cambridge University Press, Synchrotron X-ray SNR candidates discovered in the ASCA Galactic Plane Survey, M. Ueno; S. Yamauchi; A. Bamba; H. Yamaguchi; K. Koyama; K. Ebisawa; Vink, Shell-like supernova remnants (SNRs) are primary candidates for the origin of Galactic cosmic rays. However, among the known SNRs (about 220), only a small fraction has been known to exhibit the synchrotron X-ray spectrum, that is considered to be a piece of evidence for high energy particle acceleration. Synchrotron X-ray emitting SNRs are known to be systematically radio-quiet compared to the SNRs that do not emit synchrotron X-rays. Therefore, most synchrotron X-ray emitting SNR candidates may have escaped detection in the previous systematic radio surveys. On the other hand, hard X-ray surveys are effective to search for synchrotron X-ray emitting SNRs, because of its penetration power. Thus we have searched for SNRs in the ASCA Galactic Plane Survey data, the first Galactic imaging survey in > 2 keV, and discovered 14 candidates. Deep follow-up observations with ASCA, XMM, or Chandra on 5 of them revealed 2 sources to be synchrotron X-ray emitting SNRs. Furthermore we confirmed non-thermal X-ray spectra from the other 3 sources, though the origin is yet unknown. We report the observational results and discuss the X-ray origin. © 2006 International Astronomical Union., 2005, 1, 230, 333, 337, 10.1017/S1743921306008593

Not Refereed, PROGRESS OF THEORETICAL PHYSICS SUPPLEMENT, PROGRESS THEORETICAL PHYSICS PUBLICATION OFFICE, An ultrasoft transient X-ray source near the Galactic bulge region discovered with ginga, S Yamauchi; E Nakamura, An ultrasoft transient X-ray source was discovered near the Galactic bulge region with the Ginga satellite. The source position was redetermined using the revised satellite attitude data, and is in agreement with those of transient sources, KS 1732-273 and 1RXS J173602.0-272541. The X-ray spectrum was represented by a multicolor disk model with a temperature at the inner disk radius of 0.7-0.8 keV. The obtained spectral parameters are consistent with those of black hole binaries., 2004, 155, 155, 445, 446

Not Refereed, PROCEEDINGS OF THE 5TH INTEGRAL WORKSHOP ON THE INTEGRAL UNIVERSE, EUROPEAN SPACE AGENCY, A Chandra deep X-ray exposure on the Galactic plane and near infrared identification, K Ebisawa; A Paizis; TJL Couvoisier; P Dubath; M Tsujimoto; K Hamaguchi; Beckmann, V; A Bamba; A Senda; M Ueno; H Kaneda; Y Maeda; G Sato; S Yamauchi; R Cutri; E Nishihara, Using the Chandra ACIS-I instruments, we have carried out a deep X-ray observation on the Galactic plane region at (l, b) approximate to (28.degrees 5, 0.degrees 0), where no discrete X-ray sources have been known previously. We have detected, as well as strong diffuse emission, 274 new point X-ray sources (4 a confidence) within two partially overlapping fields (similar to 250 arcmin(2) in total down to the flux limit similar to 3 x 10(-15) erg s(-1) cm(-2) (2- 10 keV) and similar to 7x 10(-16) erg s(-1) cm(-2) (0.5 - 2 keV). We clearly resolved point sources and the Galactic diffuse emission, and found that similar to 90 % of the flux observed in our field of view originates from diffuse emission. Many point sources are detected either in the soft X-ray band (below 2 keV) or in the hard band (above 2 keV), and only a small number of sources are detected in both energy bands. On the other hand, most soft X-ray sources are considered to be nearby X-ray active stars. We have carried out a follow-up near-infrared (NIR) observation using SOFI at ESO/NTT. Most of the soft X-ray sources were identified, whereas only a small number of hard X-ray sources had counterparts in NIR. Using both X-ray and NIR information, we can efficiently classify the point X-ray sources detected in the Galactic plane. We conclude that most of the hard X-ray sources are background Active Galactic Nuclei seen through the Milky Way, whereas majority of the soft X-ray sources are nearby X-ray active stars., 2004, 552, 687, 690

Not Refereed, Proc. of the workshop on Galaxies and Clusters of Galaxies, Chandra Di?use X-Ray Spectrum of the Galactic Ridge, YAMAUCHI Shigeo; Sato, G; Maeda, Y; Ebisawa, K; Kaneda, H; Yamauchi, S, 2003, 13-15

Not Refereed, Proc. of Workshop ”X-ray and Radio Emission of Young Stars”, ASCA Observations of Star-forming Regions, YAMAUCHI Shigeo, 2003, 9-14

Not Refereed, CHINESE JOURNAL OF ASTRONOMY AND ASTROPHYSICS, SCIENCE PRESS, X-ray emission from galactic plane, K Ebisawa; S Yamauchi; A Bamba; M Ueno; A Senda, We report several important results obtained from recent Galactic Xray survey observations, in particular ASCA Galactic center and plane surveys and our Chandra deep survey on the (l, b) approximate to (28 degrees.5, 0 degrees.0) region. Strong hard X-ray diffuse components are observed from Galactic ridge, center and bulge, and they have both thermal and non-thermal spectral components. Dozens of discrete and extended sources have been discovered on the Galactic plane, which also indicate thermal and/or non-thermal X-ray energy spectra. They are often associated with radio sources and are considered to be SNR candidates. Most of the hard Xray point sources in the outer part of the Galactic plane are considered to be background AGNs, while fraction of the Galactic hard X-ray sources (such as quiescent dwarf novae) increases toward the Galactic center. Most of the soft Xray sources on the Galactic plane are presumably nearby active stars., 2003, 3, 281, 286

Not Refereed, Proc. of Workshop ”Black Hole Astrophysics 2002”, Chandra Deep X-Ray Observation on the Galactic Plane, YAMAUCHI Shigeo; Ebisawa, K; Paizis, A; Maeda, Y; Kaneda, H; Sato, G; Yamauchi, S; Bamba, A, 2002, 25-35

Not Refereed, Proceedings of IAU 8th Asian-Paci?c Regional Meeting, Volume II, ASCA Galactic Plane and Galactic Center Region Survey, YAMAUCHI Shigeo; Yamauchi, S; Bamba, A; Kaneda, H; Koyama, K; Kinigasa, K; Maeda,Y; Matsuzaki, K; Mitsuda, K; Murakami, H; Sakano, M; Sugizaki, M; Torii, K; Ueno, M, 2002, 81-82

Not Refereed, ASP Conference Series 277 ”Stellar Coronae in the Chandra and XMM-Newton Era”, X-Ray Study of Herbig Ae/Be Stars, Intermediate Mass Young Stars, YAMAUCHI Shigeo; Hamaguchi, K; Koyama, K; Yamauchi, S; Terada, H, 2002, 193-200

Not Refereed, FROM DARKNESS TO LIGHT: ORIGIN AND EVOLUTION OF YOUNG STELLAR CLUSTERS, ASTRONOMICAL SOC PACIFIC, X-ray emission from intermediate- to high-mass pre-main sequence stars, K Hamaguchi; H Terada; A Bamba; K Imanishi; M Ueno; K Koyama; S Yamauchi; Y Tsuboi, We present the ASCA observational results of intermediate mass to high mass pre-main-sequence stars. Seven objects in five fields were observed. Most sources exhibited significant time variability including flaring events, which suggests some magnetic activities on these stars. In the spectral analysis, younger sources in about 10(5)-years-old have higher plasma temperatures than 2keV whereas older sources have lower ones in our limited samples. The possible magnetic amplification mechanism is also discussed., 2001, 243, 627, 632

Not Refereed, X-RAY ASTRONOMY, AMER INST PHYSICS, The population of faint X-ray sources in the galaxy and their contribution to the Galactic ridge X-ray emission, M Sugizaki; K Matsuzaki; H Kaneda; S Yamauchi; K Mitsuda, The Galactic ridge X-ray emission (GRXE) is an enhanced X-ray emission along the Galactic plane, whose origin still remains unknown. The GRXE was studied for the first time in the energy band of 0.5-10 keV with a spatial resolution of 3' by the ASCA Galactic plane survey which covers the spatial area of |l| less than or similar to 45degrees and |b| less than or similar to 0.4degrees almost uniformly. We determined the large scale distribution of the GRXE after eliminating discrete X-ray sources with a flux above 10(-12.5) ergs cm(-2) s(-1) and revealed that the volume emissivity of the GRXE is highly concentrated within the 4 kpc arm. We resolved 163 discrete X-ray sources by imaging analysis and obtained the LogN-LogS relations of those sources. In the hard (2-10 keV) band, the slope of the LogN-LogS relation is significantly smaller than 1. Considering a scale height of the Galactic plane covered by the ASCA Galactic plane survey, we conclude that the slope of the LogN-LogS relation represents that the spatial distribution of the sources has a scale height as small as 10 pc, that the sources are distributed in arm-like structures, and/or that the relation reflects the luminosity function rather than the spatial distribution. We analyzed small-scale spatial intensity fluctuation of the GRXE after subtracting the large scale variations and the contributions of resolved discrete sources. The residual small-scale fluctuation is found to remain significantly over the photon-counting Poisson fluctuation. However, in the 2-10 keV band, the amplitude can be explained by the fluctuation of the cosmic X-ray background coming through the Galactic interstellar medium. From this, we can obtain a strong constraint to a flux and a number density of discrete sources if we are to explain the GRXE with a sum of discrete sources; more than 10(7) sources with the luminosity smaller than 10(31) ergs s(-1) must exist in the Galaxy. This source number density is larger by three orders of magnitude than that of CVs in the solar neighborhood, which would be a plausible candidate for the discrete source origin. Thus, We conclude that the diffuse emission origin should be much more probable even if it has large problems., 2001, 599, 959, 962

Not Refereed, NEW CENTURY OF X-RAY ASTRONOMY, ASTRONOMICAL SOC PACIFIC, X-ray emission from intermediate-mass young stars herbig Ae/Be stars, K Hamaguchi; K Koyama; S Yamauchi; H Terada, We studied the X-ray properties of intermediate-mass young stars Herbig Ae/be stars, by using observed and archival data with the Japanese X-ray satellite ASCA. From the spectral and timing analyses of 15 detected sources among 39 targets, we concluded that the X-ray emission is probably originated in the magnetic activity, linking between a star and its circumstellar disk. From the comparison of X-ray properties, we suggest that these X-ray activities continues to the former phase of massive main-sequence stars., 2001, 251, 240, 241

Not Refereed, NEW CENTURY OF X-RAY ASTRONOMY, ASTRONOMICAL SOC PACIFIC, ASCA observations of two molecular cloud cores in the Perseus molecular cloud complex, S Yamauchi; Y Tsuboi; K Koyama, We report ASCA observations of two molecular cloud cores in the Perseus molecular cloud complex, Barnard I and the core containing a Class 0 protostar, IRAS 03282+3035. We detected 4 X-ray sources and found counterparts for two of them. We found no X-ray emission from young IRAS sources, IRAS 03282+3035 and IRAS 03301+3057, and obtained upper limits of their X-ray emissions., 2001, 251, 286, 287

Not Refereed, NEW CENTURY OF X-RAY ASTRONOMY, ASTRONOMICAL SOC PACIFIC, Chandra observation of a blank Galactic plane region, K Ebisawa; Y Maeda; H Kaneda; S Yamauchi, We have carried out a Chandra ACIS-I observation on a typical Galactic plane where no previous X-ray sources have been known. We have discovered more than 50 unidentified sources in the 3-8 keV band above the flux level similar to 3 x 10(-15) ergs/s/cm(2) at the 3 sigma confidence level. The total point source flux accounts for only 10 % of the total X-ray flux in the field of view. The observed source number density shows little excess over the extragalactic log N - log S curve determined from high Galactic latitude regions. The present result indicates that significant parts of the detected sources have extragalactic origin. The Galactic Ridge hard X-ray Emission has truly diffuse origin, and there are few Galactic X-ray sources as dim as similar to 3 x 10(-15) ergs/s/cm(2) (2 - 10 keV)., 2001, 251, 298, 299

Not Refereed, NEW CENTURY OF X-RAY ASTRONOMY, ASTRONOMICAL SOC PACIFIC, Overall properties of the galactic ridge X-ray emission, H Kaneda; S Yamauchi; K Ebisawa; M Sugizaki, The current understanding of Galactic Ridge X-ray Emission (GRXE) is summarized on the basis of observational results from ASCA and the other new missions. GRXE possibly originates from a truly diffuse interstellar plasma, not a collection of discrete sources., 2001, 251, 302, 303

Not Refereed, NEW CENTURY OF X-RAY ASTRONOMY, ASTRONOMICAL SOC PACIFIC, Diffuse hard X-ray emission in the galactic bulge, M Kokubun; K Makishima; M Sakano; S Yamauchi; K Ebisawa, The bulge X-ray emission has been systematically studied with the ASCA and RXTE satellites. After removing the contribution from point sources, the presence of diffuse bulge X-ray emission consisting three distinct emission components, two thermal (cooler and hotter) and one non-thermal, has been established. The temperatures of the thermal components are essentially constant (0.6 keV and 3 keV) all over the bulge region, and surface brightness distributions of the hotter and non-thermal components are strongly correlated with each other. From the estimated scale of the hard X-ray bulge, total X-ray luminosity of the bulge emission is estimated to be similar to 10(38) erg s(-1), which is almost comparable to that of the well-known GRXE., 2001, 251, 304, 305

Not Refereed, NEW CENTURY OF X-RAY ASTRONOMY, ASTRONOMICAL SOC PACIFIC, X-ray source population of the Galactic center region obtained with ASCA, M Sakano; K Koyama; H Murakami; Y Maeda; S Yamauchi, Front the ASCA X-ray point-source list in the Galactic center 5 x 5 degree(2) region, we found the clear correlation between the position of the sources and the absorption. This fact implies that the major part of the absorption is due to the cold interstellar matter (ISM) in the line of sight. Using the correlation, we estimate the distribution of the cold ISM. We also found that the ratio of numbers of high mass binaries to low mass binaries is significantly smaller than that in the whole Galaxy or SMC, which implies that the past starburst activity in the Galactic center region was rather quiet., 2001, 251, 314, 315

Not Refereed, NEW CENTURY OF X-RAY ASTRONOMY, ASTRONOMICAL SOC PACIFIC, Development of the ISAS Ginga archive, K Asai; A Yamagishi; A Yamashita; M Watanabe; T Dotani; K Mitsuda; F Nagase; K Ebisawa; S Yamauchi; A Yoshida; S Kitamoto; Hatsukade, I, We report on the development of the ISAS Ginga archive. At ISAS, all the Ginga archive and analysis software were originally developed on the main-frame computers. We are installing them to the UNIX environment with minor modification so that all the analysis will become possible in the modern network computing environment. The archive will be made public from ISAS PLAIN Center (Center for Planning and information systems) in near future., 2001, 251, 514, 515

Not Refereed, 天文月報, 「あすか」衛星による銀河面サーベイ観測, YAMAUCHI Shigeo, Jun. 2000, 93, 6, 293-299

Not Refereed, Publications of the Astronomical Society of Japan, Astronomical Society of Japan, X-ray flares from an Hα emission-line star in the Orion region, Kiso A0904-105, Shigeo Yamauchi; Reiko Kamimura; Katsuji Koyama, We analyzed ASCA data, including the reflection nebula NGC 2023, and discovered two X-ray flares from an Hα emission-line star, Kiso A0904-105, located at ∼ 30′ to the southwest of NGC 2023. The separation time between the two flares was ≃ 4 hr. The temperatures of the first and second flares reached (5-7) × 107 K and the luminosities around the flare peaks were ≃ 1033 erg s-1 (0.5-10.0 keV energy band, assuming the distance of 400 pc), which are comparable to those of the giant X-ray flares from T Tauri stars. After the flare peaks, X-ray intensity exhibited an exponential decay. Comparing the flares with those from T Tauri stars, we found that the physical parameters in the flaring plasma were within the range of those obtained from T Tauri stars., 2000, 52, 1, 161, 166, 10.1093/pasj/52.1.161

Not Refereed, Proc. of Japanese-German Workshop on High Energy Astrophysics, ASCA Observations of the Chamaeleon Clouds, YAMAUCHI Shigeo, 1999, 22-25

Not Refereed, Proc. of Japanese-German Workshop on High Energy Astrophysics, X-Ray and Radio Observations of NGC 1333 Star Forming Region, YAMAUCHI Shigeo; Itoh, M; Fukunaga, H; Sekimoto, Y; Tatematsu, K; Koyama, K; Tsuboi, Y; Yamauchi, S; Kobayashi, N; Hayashi, M; Ueno, S, 1999, 49-51

Not Refereed, Proc. of Japanese-German Workshop on High Energy Astrophysics, Non-thermal Emission from the Shell-like Supernova Remnants, YAMAUCHI Shigeo; Tomida, H; Koyama, K; Yamauchi, S; Yokogawa, J, 1999, 81-85

Not Refereed, Proc. of Japanese-German Workshop on High Energy Astrophysics, X-Ray SNRs found with the ASCA Galactic Plane Survey Pro ject, YAMAUCHI Shigeo; Yamauchi, S; ASCA Galactic; Plane Survey team, 1999, 110-112

Not Refereed, Proc. of International Workshop ”Star Formation 1999”, ASCA Observations of the Monoceros OB1 Molecular Cloud, YAMAUCHI Shigeo; Nakano, M; Yamauchi, S; Sugitani, K; Ogura, K, 1999, 318-319

Not Refereed, ASTROPHYSICAL JOURNAL, UNIV CHICAGO PRESS, Discovery of the faint X-ray pulsar AX J1820.5-1434 with ASCA, K Kinugasa; K Torii; Y Hashimoto; H Tsunemi; K Hayashida; S Kitamoto; Y Kamata; T Dotani; F Nagase; M Sugizaki; Y Ueda; N Kawai; K Makishima; S Yamauchi, A new X-ray pulsar, AX J1820.5-1434, has been discovered during the ASCA Galactic plane survey project on April 9, at R.A. = 18(h)20(m)29.(s)5, decl. = -14 degrees 34'24 " (equinox 2000.0; error radius 0.'5). A coherent pulsation was detected from the source with an apparent barycentric pulse period of 152.26 +/- 0.04 s. The mean flux, not corrected for the interstellar absorption, was 2.3 x 10(-11) ergs s(-1) cm(-2) in the 2-10 keV energy band. The energy spectra obtained by the GIS and SIS can be fitted by a power-law model (photon index = 0.9 +/- 0.2) with a large column density of 9.8 +/- 1.7 x 10(22) H atoms cm(-2). These parameters indicate that the new pulsar is a highly obscured accretion-driven binary X-ray pulsar. This discovery of a faint pulsar suggests existence of many hidden pulsars in our Galaxy., Mar. 1998, 495, 1, 435, 439, 10.1086/305291

Not Refereed, 日本天文学会年会講演予稿集, Trace of galaxy cluster deep impact in the Sharpley super galaxy cluster region., 花見仁史; 山内茂雄; 鶴剛; 小山勝二; 嶋作一大; 池辺靖, 1998, 1998, 142

Not Refereed, HOT UNIVERSE, KLUWER ACADEMIC PUBL, Hot plasma in the galaxy, S Yamauchi, 1998, 188, 47, 50

Not Refereed, HOT UNIVERSE, KLUWER ACADEMIC PUBL, ASCA observation of NGC1333 star forming region, M Itoh; H Fukunaga; K Koyama; Y Tsuboi; S Yamauchi; N Kobayashi; M Hayashi; S Ueno, 1998, 188, 228, 229

Not Refereed, HOT UNIVERSE, KLUWER ACADEMIC PUBL, ASCA observations of Class I protostars in the Rho Oph dark cloud, Y Tsuboi; K Koyama; Y Kamata; S Yamauchi, 1998, 188, 236, 237

Not Refereed, HOT UNIVERSE, KLUWER ACADEMIC PUBL, Discovery of X-ray emission from the radio SNR G352.7-0.1, K Kinugasa; K Torii; H Tsunemi; S Yamauchi; K Koyama; T Dotani, 1998, 188, 251, 252

Not Refereed, HOT UNIVERSE, KLUWER ACADEMIC PUBL, ASCA observations of the SgrA region, Y Maeda; K Koyama; H Murakami; M Sakano; K Ebisawa; T Takeshima; S Yamauchi, 1998, 188, 352, 353

Not Refereed, Astrophysical Journal, Institute of Physics Publishing, Hard X-ray emission from the Galactic ridge, N. Y. Yamasaki; T. Ohashi; F. Takahara; S. Yamauchi; K. Koyama; T. Kamae; H. Kaneda; K. Makishima; Y. Sekimoto; M. Hirayama; T. Takahashi; T. Yamagami; S. Gunji; T. Tamura; S. Miyazaki; M. Nomachi, Hard X-ray and γ-ray emissions from the Galactic ridge were studied with the large area proportional counter (LAC) on the Ginga satellite and a balloon-borne detector Welcome-1. In the scanning observations with the LAC, diffuse hard X-rays were detected along the Galactic plane between l = -20° and l = 40°. The measured spectrum shows that a hard component exists in the Galactic ridge emission above 10 keV, in addition to the hot plasma component. The estimated luminosity of the Galactic ridge emission is around 2 × 1038 ergs s-1 in the 3-16 keV band. Welcome-1 observed the γ-ray ridge emission at around l ∼ 345° between 50 and 600 keV. These two results and a recent COMPTEL study suggest that the spectrum of the diffuse Galactic ridge emission extends over the keV-MeV range. From the observed spectral slope, bremsstrahlung by electrons is shown to be the dominant emission mechanism. This implies that low-energy electrons must be supplied continuously to sustain emission in the hard X-ray band. We propose a scenario in which the thermal electrons in the hot plasma responsible for the strong Fe K X-ray emission are shock-accelerated continuously in supernova remnants (SNRs), producing the observed hard X-ray and γ-ray emissions from the Galactic ridge. © 1997. The American Astronomical Society. All rights reserved., 1997, 481, 2, 821, 831, 10.1086/304097

Not Refereed, Proc. of International conference ”X-ray Imaging and Spectroscopy of Cosmic Hot Plasmas”, ASCA Observations of Galactic Ridge Emission, YAMAUCHI Shigeo; Yamauchi, S; Kaneda, H; Koyama, K; Makishima, K; Matsuzaki, K; Sonobe, T; Tanaka, Y; Yamasaki, N, 1997, 145-148

Not Refereed, Proc. of International workshop ”All-sky X-ray Observations in the Next Decade”, Transient Sources in the Galactic Plane: First Results of the Galactic Plane Survey Project, YAMAUCHI Shigeo; Koyama, K; Nishiuchi, M; Kamata, Y; Sugizaki, M; Yamauchi, S; ASCA Galactic; Plane Survey team, 1997, 45-47

Not Refereed, Proc. of International workshop ”All-sky X-ray Observations in the Next Decade”, A New Eclipsing Burster near the Galactic Center, YAMAUCHI Shigeo; Maeda, Y; Koyama, K; Sakano, M; Takeshima, T; Yamauchi, S, 1997, 117-122

Not Refereed, Proc. of ASCA/ROSAT Workshop on Clusters of Galaxies, ASCA Survey of the Shapley Supercluster, YAMAUCHI Shigeo; Hanami, H; Shimasaku, K; Tsuru, T; Yamauchi, S; Koyama, K, 1997, 189-190

Not Refereed, Publications of the Astronomical Society of Japan, Astronomical Society of Japan, Discovery of an 11-s X-ray pulsar in the galactic-plane section of the scorpius constellation, Mutsumi Sugizaki; Fumiaki Nagase; Ken'ichi Torii; Kenzo Kinugasa; Tatsuhiko Asanuma; Keiichi Matsuzaki; Katsuji Koyama; Shigeo Yamauchi, During a galactic-plane survey with ASCA in 1996 September, we detected a relatively bright, soft source at R.A. = 17h8m46.s6, DEC. = -40°9′27″ (J2000), and discovered an 11-s X-ray pulsation from the source. This source has been identified with the ROSAT source 1RXS J170849.0-400910. From a timing analysis of the source, we obtained a barycentric pulse period of P = 10.99759±0.00005 s with a broad sinusoidal shape of a pulse fraction of ∼ 30%. The energy spectrum in the 0.8-10 keV region is very soft, and can be fitted by a power-law model with a photon index of 3.5 and an absorption column density of 1.8 × 1022 cm-2. The observed pulse-phase-averaged flux in the range 0.8-10 keV is 4.3 × 10-11 erg cm-2 s-1, which corresponds to 1.7 × 10-10 erg cm-2 s-1 after correcting for soft X-ray absorption. During an observation interval of about 14 hr, neither a significant change in the pulsation period, nor a significant variation in the phase-averaged flux was detected. From these X-ray properties, we suggest that this newly discovered X-ray pulsar might be a member of a small subgroup of "anomalous" X-ray pulsars with a period close to 6-9 s., 1997, 49, 5, L25, L30, 10.1093/pasj/49.5.L25

Not Refereed, Proc. of International conference ”UV and X-Ray Spectroscopy of Astrophysical and Laboratory Plasmas”, ASCA Observation of PMS Stars in the ρ Ophiuchi Dark Cloud Cores, YAMAUCHI Shigeo; Kamata, Y; Koyama, K; Maeda, Y; Ozaki, M; Tawara, Y; Ueno, S; Yamauchi, S, 1996, 283-286

Not Refereed, Proc. of International conference ”UV and X-Ray Spectroscopy of Astrophysical and Laboratory Plasmas”, ASCA Observation of Supernova Remnant RX 04591+5147, YAMAUCHI Shigeo; Yamauchi, S; Tamura, K; Koyama, K; ASCA team, 1996, 315-318

Not Refereed, Proc. of International workshop ”Roentgenstrahlung from the Universe”, ASCA Observations of Pre-Main-Sequence Stars, YAMAUCHI Shigeo; Skinner, S.L; Walter, F. M; Yamauchi, S, 1996, 69-70

Not Refereed, Abstracts of the meeting of the Physical Society of Japan. Sectional meeting, 一般社団法人日本物理学会, 1p-J-2 Hot Gaseous Components in Spiral Galaxies and Their X-ray Emissions, Makishima K; Ikebe Y; Fukazawa Y; Kaneda H; Atsushita K; Tamura T; Ohashi T; Yamasaki N; Yamauchi S; Tsuru T, 12 Sep. 1994, 1994, 1, 173, 173

Not Refereed, PUBLICATIONS OF THE ASTRONOMICAL SOCIETY OF JAPAN, ASTRONOMICAL SOC JAPAN, ASCA OBSERVATIONS OF HARD X-RAY-EMISSION FROM THE RHO-OPHIUCHI DARK CLOUD, K KOYAMA; Y MAEDA; M OZAKI; S UENO; Y KAMATA; Y TAWARA; S SKINNER; S YAMAUCHI, ASCA obtained broad-band (0.8-12 keV) images and spectra of the central region of the Rho Ophiuchi dark cloud in 1993 August. The 38-ks observation detected at least eleven sources (S/N greater-than-or-equal-to 3), including the X-ray bright pre-main-sequence star DoAr 21 and embedded infrared sources with no optical counterparts. Hard X-rays up to almost-equal-to 8 keV were detected from DoAr 21 (whose light curve shows no evidence for variability) and from a flaring source lying in a region of high visual extinction. Thermal spectral fits for the brightest source give kT almost-equal-to 2 keV and hydrogen column densities N(H) almost-equal-to 1022 cm-2. The spectrum of a region in the center of the field where no discrete sources were detected shows hard, heavily absorbed emission that is most likely the integrated contribution of a number of deeply embedded young stars below the detection limit., 1994, 46, 3, L125, L129

Not Refereed, PUBLICATIONS OF THE ASTRONOMICAL SOCIETY OF JAPAN, ASTRONOMICAL SOC JAPAN, A NONTHERMAL X-RAY-SPECTRUM FROM THE SUPERNOVA REMNANT W-50, S YAMAUCHI; N KAWAI; T AOKI, Hard X-ray properties of the supernova remnant W 50 are presented. The extended lobe structure is confirmed in the 0.7-10 keV energy band. The surface brightness in the 0.7-4 keV band has a clear peak at the region far from SS 433, similar to that obtained by the Einstein Observatory. The shape in the high energy band (4-10 keV) is roughly consistent with that in the low energy band (0.7-4 keV), but shows a flat top structure. The X-ray spectrum from the extended structure shows a non-thermal spectrum without apparent emission lines. The spectrum becomes harder as the distance from SS 433 decreases. We discuss the origin of the X-rays in terms of synchrotron emission., 1994, 46, 3, L109, L113

Not Refereed, 日本天文学会年会講演予稿集, 「ぎんが」によるNGC2110のX線観測 II, 林一蔵; 小山勝二; 山内茂雄; 鶴剛; 上野史郎; 粟木久光, 1993, 1993, C118

Not Refereed, BACK TO THE GALAXY, AIP PRESS, X-RAY HALO FROM THE GALACTIC BULGE - THE 6.7 KEV LINE MAPPING, K KOYAMA; S YAMAUCHI, 1993, 278, 107, 114

Not Refereed, 日本天文学会年会講演予稿集, 「ぎんが」によるSN1006の観測, 尾崎正伸; 山内茂雄; 上野史郎; 鶴剛; 小山勝二, 1992, 1992, A036

Not Refereed, Proc. of International conference ”Frontiers of X-Ray Astronomy”, Ginga Observations of a Binary X-Ray Pulsar EXO 2030+375, YAMAUCHI Shigeo; Sun, X. J; Kawai, N; Matsuoka, M; Yoshida, A; Yamauchi, S; Koyama, K, 1992, 95-96

Not Refereed, Proc. of International conference ”Frontiers of X-Ray Astronomy”, Hot Halo around the Galactic Bulge, YAMAUCHI Shigeo; Yamauchi, S; Koyama, K; Tsuru, T, 1992, 407-408

Not Refereed, STRUCTURE AND EVOLUTION OF NEUTRON STARS, ADDISON-WESLEY PUBL CO, NEW X-RAY SOURCES NEAR THE GALACTIC BULGE REGIONS, S YAMAUCHI; K KOYAMA, 1992, 206, 208

Not Refereed, Proc. of International workshop ”The X-Ray Background”, BBXRT Observations of the DXRB: First Results, YAMAUCHI Shigeo; Jahoda, K; Serlemitsos, P. J; Arnaud, K. A; Boldt, E; Holt, S; Marshall, F. E; Mushotzky, R. F; Petre, R; Sanders, W. T; Smale, A; Swank, J; Szymkowiak, A; Weaver, K; Yamauchi, S, 1992, 240-258

Not Refereed, 宇宙科学研究報告, Japan Aerospace Exploration Agency, 銀河中心の X 線観測, YAMAUCHI Shigeo, Two obsevations of the Galactic Center with the Ginga satellite have been performed; one is the lunnar occultation observation and the other is the 6.7keV iron line mapping observation. Two kinds of diffuse X-ray emission and several X-ray point sources have been detected in the Galactic Center Region. The diffuse X-ray emission is considered as that from an optically thin hot plasma. We suggest that energetic explosions took place near the Galactic Center., 1990, 25, 215-221, 221

Not Refereed, Proc. of International conference ”Physics of Neutron Stars and Black Holes”, Transient X-Ray Pulsar with 414 sec Period Discovered by Ginga, YAMAUCHI Shigeo; Tawara, Y; Yamauchi, S; Awaki, H; Kii, T; Koyama, K; Nagase, F, 1988, 71-74

Publications of the Astronomical Society of Japan, Astronomical Society of Japan, ASCA Observations on Two Molecular Cloud Cores in the Perseus Complex, YAMAUCHI Shigeo; TSUBOI Yohko; KOYAMA Katsuji, 25 Oct. 2001, 53, 5, 885, 892

日本天文学会年会講演予稿集, XRISM搭載軟X線撮像装置Xtendのフライト用CCD素子の性能評価, 金丸善朗; 佐藤仁; 高木駿亨; 寺田裕大; 住田知也; 森浩二; 齋藤真梨子; 信川久実子; 山内茂雄; 迫聖; 信川正順; 田中孝明; 内田裕之; 天野雄輝; 尾近洗行; 鶴剛; 花岡真帆; 米山友景; 岡崎貴樹; 朝倉一統; 佐久間翔太郎; 服部兼吾; 石倉彩美; 野田博文; 林田清; 松本浩典; 冨田洋; 樫村晶; 中嶋大; 卜部夕希乃; 平賀純子; 村上弘志; 内山秀樹; 山内誠; 廿日出勇; 幸村孝由; 萩野浩一; 小林翔悟; 山岡和貴; 堂谷忠靖; 尾崎正伸; 常深博, 2020, 2020

日本天文学会年会講演予稿集, XRISM搭載XtendのGrade-dependent offset補正の調査, 迫聖; 信川正順; 齋藤真梨子; 信川久実子; 山内茂雄; 佐藤仁; 金丸善朗; 高木駿亨; 西岡祐介; 森浩二; 林田清; 冨田洋; 尾近洸行; 天野雄輝; 田中孝明; 内田裕之; 鶴剛; 樫村晶; 中嶋大; 米山友景; 岡崎貴樹; 朝倉一統; 花岡真帆; 服部兼吾; 佐久間翔太郎; 野田博文; 松本浩典; 常深博; 村上弘志; 内山秀樹; 山内誠; 廿日出勇; 幸村孝由; 萩野浩一; 小林翔悟; 山岡和貴; 卜部夕希乃; 平賀純子; 尾崎正伸; 堂谷忠靖, 2020, 2020

日本天文学会年会講演予稿集, XRISM搭載Xtendの新しいCTI補正方法の検討, 齋藤真梨子; 信川久実子; 山内茂雄; 信川正順; 迫聖; 金丸善朗; 佐藤仁; 高木駿亨; 森浩二; 山内誠; 廿日出勇; 林田清; 野田博文; 松本浩典; 米山友景; 花岡真帆; 岡崎貴樹; 朝倉一統; 佐久間翔太郎; 服部兼吾; 石倉彩美; 常深博; 冨田洋; 田中孝明; 内田裕之; 天野雄輝; 尾近洸行; 鶴剛; 樫村晶; 中嶋大; 村上弘志; 内山秀樹; 幸村孝由; 萩野浩一; 小林翔悟; 山岡和貴; 卜部夕希乃; 平賀純子, 2020, 2020

日本天文学会年会講演予稿集, X線分光撮像衛星XRISMによる天の川銀河中心の観測計画, 信川正順; 山内茂雄; 内山秀樹; 信川久実子; 村上弘志; 鶴剛; 前田良知; 野田博文, 2020, 2020

日本天文学会年会講演予稿集, XRISM搭載Xtendのフライト用CCDの電荷転送非効率の調査, 金丸善朗; 佐藤仁; 高木駿亨; 寺田裕大; 住田知也; 森浩二; 齋藤真梨子; 山内茂雄; 信川久実子; 迫聖; 信川正順; 田中孝明; 内田裕之; 天野雄輝; 尾近洸行; 鶴剛; 花岡真帆; 米山友景; 岡崎貴樹; 朝倉一統; 佐久間翔太郎; 服部兼吾; 石倉彩美; 野田博文; 林田清; 松本浩典; 冨田洋; 吉田鉄生; 樫村晶; 中嶋大; 卜部夕希乃; 平賀純子; 村上弘志; 内山秀樹; 山内誠; 廿日出勇; 幸村孝由; 萩野浩一; 小林翔悟; 山岡和貴; 堂谷忠靖; 尾崎正伸; 常深博, 2020, 2020

日本天文学会年会講演予稿集, X線分光撮像衛星XRISM搭載軟X線撮像装置Xtendのフライト用X線CCD素子の性能評価:Grade間における波高値の違いの評価, 齋藤真梨子; 信川久実子; 山内茂雄; 信川正順; 迫聖; 金丸善朗; 佐藤仁; 高木駿亨; 森浩二; 山内誠; 廿日出勇; 林田清; 野田博文; 松本浩典; 米山友景; 岡崎貴樹; 朝倉一統; 常深博; 冨田洋; 田中孝明; 内田裕之; 天野雄輝; 鶴剛; 中嶋大; 村上弘志; 内山秀樹; 幸村孝由; 萩野浩一; 小林翔悟; 山岡和貴; 平賀純子, 2019, 2019

Meeting abstracts of the Physical Society of Japan, The Physical Society of Japan (JPS), 23a-J-9 Study of the Galactic Ridge X-ray Emission(II), Kaneda H.; Makishima K.; Matsuzaki K.; Koyama K.; Yamauchi S.; Yamasaki N.; Sugizaki M., 02 Sep. 1997, 52, 2, 79, 79

Meeting abstracts of the Physical Society of Japan, The Physical Society of Japan (JPS), Observation of the Galactic Bulge with ASCA, Kokubun N.; Makishima K.; Sakano M.; Yamauchi S.; Kamae T., 10 Sep. 2000, 55, 2, 66, 66

Abstracts of the meeting of the Physical Society of Japan. Annual meeting, The Physical Society of Japan (JPS), Study of the Galactic Ridge X-ray Emission, Kaneda H.; Makishima K.; Tashiro M.; Matsuzaki K.; Sugizaki M.; Tanaka Y.; Yamauchi S.; Yamasaki N., 16 Mar. 1995, 50, 1, 132, 132

Publications of the Astronomical Society of Japan, Astronomical Society of Japan, ASCA Observations of the Supernova Remnant G156.2+5.7, YAMAUCHI Shigeo; KOYAMA Katsuji; TOMIDA Hiroshi; YOKOGAWA Jun; TAMURA Keisuke, 25 Feb. 1999, 51, 1, 13, 22

Not Refereed, IEEE Nuclear Science Symposium Conference Record, In-flight status of the X-ray observatory Suzaku, T. Dotani; K. Mitsuda; M. Bautz; H. Inoue; R. L. Kelley; K. Koyama; H. Kunieda; K. Makishima; Y. Ogawara; R. Petre; T. Takahashi; H. Tsunemi; N. E. White; N. Anabuki; L. Angelini; K. Arnaud; H. Awaki; A. Bamba; K. Boyce; G. V. Brown; K. W. Chan; J. Cottam; J. Doty; K. Ebisawa; Y. Ezoe; A. C. Fabian; E. Figueroa; R. Fujimoto; Y. Fukazawa; T. Furusho; A. Furuzawa; K. Gendreau; R. E. Griffiths; Y. Haba; K. Hamaguchi; I. Harrus; G. Hasinger; I. Hatsukade; K. Hayashida; P. J. Henry; J. S. Hiraga; S. S. Holt; A. Hornschemeier; J. P. Hughes; U. Hwang; M. Ishida; Y. Ishisaki; N. Isobe; M. Itoh; N. Iyomoto; S. M. Kahn; T. Kamae; H. Katagiri; J. Kataoka; H. Katayama; N. Kawai; M. Kawaharada; C. Kilbourne; K. Kinugasa; S. Kissel; S. Kitamoto; M. Kohama; T. Kohmura; M. Kokubun; T. Kotani; J. Kotoku; A. Kubota; G. M. Madejski; Y. Maeda; F. Makino; A. Markowitz; C. Matsumoto; H. Matsumoto; M. Matsuoka; K. Matsushita; D. McCammon; T. Mihara; K. Misaki; E. Miyata; T. Mizuno; K. Mori; H. Mori; M. Morii; H. Moseley; K. Mukai; H. Murakami; T. Murakami; R. Mushotzky; F. Nagase; M. Namiki; H. Negoro; K. Nakazawa; J. A. Nousek; T. Okajima; Y. Ogasaka; T. Ohashi; T. Oshima; N. Ota; M. Ozaki; H. Ozawa; A. N. Parmar; W. D. Pence; F. Scott Porter; J. N. Reeves; G. R. Ricker; I. Sakurai; W. T. Sanders; A. Senda; P. Serlemitsos; R. Shibata; K. Shinozaki; Y. Soong; R. Smith; M. Suzuki; A. E. Szymkowiak; H. Takahashi; Y. Takei; T. Tamagawa; K. Tamura; T. Tamura; Y. Tanaka; M. Tashiro; Y. Tawara; Y. Terada; Y. Terashima; H. Tomida; K. Torii; Y. Tsuboi; Y. Tsujimoto; T. Tsuru; M. J.L. Turner; Y. Uchiyama; Y. Ueda; S. Ueno; M. Ueno; S. Uno; Y. Urata; S. Watanabe; N. Yamamoto; K. Yamaoka; N. Y. Yamasaki; K. Yamashita; M. Yamauchi; S. Yamauchi; T. Yaqoob; D. Yonetoku; A. Yoshida, We report in-flight status of the X-ray detectors on board the Suzaku observatory, the 5th X-ray astronomy satellite of Japan launched on July 10, 2005. Suzaku is equipped with two types of Instruments: one is the X-ray Imaging Spectrometers (XISs) and the other is Hard X-ray Detector (HXD). XIS utilizes the X-ray CCD camera in combination with the grazing-incidence X-ray telescope. HXD is a non-imaging, hybrid detector utilizing Si PIN diodes and GSO/BGO phoswich counters. Suzaku takes a low-earth, circular orbit with an altitude of 560 km and an inclination of 31 deg. This means that Suzaku goes through the south atlantic anomaly about 1/3 of its revolutions. This has a large impact on the in-flight performance of XIS and HXD, which is reported in detail in the present paper. © 2007 IEEE., 2007, 4, 2526, 2531, 10.1109/NSSMIC.2007.4436667

日本天文学会年会講演予稿集, X線分光撮像衛星XRISMの科学運用に向けての模擬試験, 林克洋; 田代信; 田代信; 寺田幸功; 寺田幸功; 高橋弘充; 信川正順; 水野恒史; 宇野伸一郎; 久保田あや; 中澤知洋; 渡辺伸; 飯塚亮; 佐藤理江; 米山友景; 吉田鉄生; BALUTA Chris; 海老沢研; 江口智士; 深澤泰司; 橋口葵; 勝田哲; 北口貴雄; 小高裕和; 大野雅功; 太田直美; 阪間美南; 阪本菜月; 志達めぐみ; 塩入匠; 丹波翼; 谷本敦; 寺島雄一; 坪井陽子; 内田和海; 内田悠介; 内山秀樹; 山田智史; 山内茂雄, 2023, 2023

日本天文学会年会講演予稿集, X線分光撮像衛星XRISMの観測データ処理ツールの開発状況, 山田智史; 田代信; 田代信; 寺田幸功; 寺田幸功; 高橋弘充; 信川正順; 水野恒史; 宇野伸一郎; 久保田あや; 中澤知洋; 渡辺伸; 飯塚亮; 佐藤理江; 林克洋; 米山友景; 吉田鉄生; BALUTA Chris; 海老沢研; 江口智士; 深澤泰司; 橋口葵; 勝田哲; 北口貴雄; 小高裕和; 大野雅功; 太田直美; 阪間美南; 阪本菜月; 志達めぐみ; 塩入匠; 丹波翼; 谷本敦; 寺島雄一; 坪井陽子; 内田和海; 内田悠介; 内山秀樹; 山内茂雄, 2023, 2023

日本天文学会年会講演予稿集, X線分光撮像衛星XRISMの科学運用準備の現状(2), 米山友景; 田代信; 田代信; 寺田幸功; 寺田幸功; 高橋弘充; 信川正順; 水野恒史; 宇野伸一郎; 久保田あや; 中澤知洋; 渡辺伸; 飯塚亮; 佐藤理江; 林克洋; 吉田鉄生; BALUTA Chris; 海老沢研; 江口智士; 深澤泰司; 橋口葵; 勝田哲; 北口貴雄; 小高裕和; 大野雅功; 太田直美; 阪間美南; 阪本菜月; 志達めぐみ; 塩入匠; 丹波翼; 谷本敦; 寺島雄一; 坪井陽子; 内田和海; 内田悠介; 内山秀樹; 山田智史; 山内茂雄, 2023, 2023

日本物理学会講演概要集(CD-ROM), Status report of the XRISM science operation, 内田悠介; 田代信; 田代信; 寺田幸功; 寺田幸功; 高橋弘充; 信川正順; 水野恒史; 宇野伸一郎; 久保田あや; 中澤知洋; 渡辺伸; 飯塚亮; 佐藤理江; 米山友景; 吉田鉄生; BALUTA Chris; 海老沢研; 江口智士; 深澤泰司; 橋口葵; 林克洋; 勝田哲; 北口貴雄; 小高裕和; 大野雅功; 太田直美; 阪間美南; 阪本菜月; 志達めぐみ; 塩入匠; 丹波翼; 谷本敦; 寺島雄一; 坪井陽子; 内田和海; 内山秀樹; 山田智史; 山内茂雄, 2023, 78, 1

日本天文学会年会講演予稿集, X線分光撮像衛星XRISMの科学運用準備の現状(3), 林克洋; 田代信; 寺田幸功; 高橋弘充; 信川正順; 水野恒史; 宇野伸一郎; 久保田あや; 中澤知洋; 渡辺伸; 飯塚亮; 佐藤理江; 星野晶夫; 吉田鉄生; 小川翔司; 金丸善朗; BALUTA Chris; 海老沢研; 江口智士; 小高裕和; 勝田哲; 北口貴雄; 新居田祐基; 太田直美; 阪本菜月; 志達めぐみ; 塩入匠; 白木天音; 谷本敦; 寺島雄一; 坪井陽子; 内田和海; 内田悠介; 内山秀樹; 山田智史; 山内茂雄; 米山友景, 2023, 2023

Oral presentation, 11 Mar. 2024, 15 Mar. 2024

Oral presentation, 11 Mar. 2024, 15 Mar. 2024

Oral presentation, 11 Mar. 2024, 15 Mar. 2024

Oral presentation

Oral presentation, 20 Sep. 2023, 22 Sep. 2023

Oral presentation, 20 Sep. 2023, 22 Sep. 2023

Oral presentation, 20 Sep. 2023, 22 Sep. 2023

Oral presentation, 20 Sep. 2023, 22 Sep. 2023

Oral presentation, 20 Sep. 2023, 22 Sep. 2023

Oral presentation, 20 Sep. 2023, 22 Sep. 2023

YAMAUCHI Shigeo, 日本天文学会春季年会, 近傍銀河団 IGR J17448-3232 の高温プラズマの調査, Mar. 2019, False

YAMAUCHI Shigeo, 日本天文学会春季年会, 銀河中心に位置する超新星残骸Sgr A Eastの再結合優勢プラズマおよび中性 鉄輝線の起源, Mar. 2019, False

YAMAUCHI Shigeo, 日本天文学会春季年会, 超新星残骸 IC 443 の過電離プラズマに対する低エネルギー宇宙線の寄与, Mar. 2019, False

YAMAUCHI Shigeo, 日本天文学会春季年会, すざく衛星を用いた超新星残骸 HB9 の高温プラズマの観測, Mar. 2019, False

YAMAUCHI Shigeo, 日本天文学会春季年会, すざく衛星による W51 領域からの中性鉄輝線の発見, Mar. 2019, False

YAMAUCHI Shigeo, 日本天文学会秋季年会, すざく衛星による超新星残骸 IC 443からの中性鉄輝線の発見, Sep. 2018, False

YAMAUCHI Shigeo, 日本天文学会春季年会, 超新星残骸G323.7-1.0における6.4 keV鉄輝線と低温プラズマの発見, Mar. 2018, False

YAMAUCHI Shigeo, 日本天文学会春季年会, X 線天文衛星「すざく」による超新星残骸 Sgr A East の過電離プラズマの探査, Mar. 2018, False

YAMAUCHI Shigeo, 日本天文学会春季年会, すざく衛星による超新星残骸IC 443の過電離プラズマの電離状態の調査, Mar. 2018, False

YAMAUCHI Shigeo, 日本天文学会春季年会, XMM-Newton 衛星による系外惑星 HD189733b のトランジット観測, Mar. 2018, False

YAMAUCHI Shigeo, 日本天文学会春季年会, X 線衛星代替機 XARM における科学運用計画, Mar. 2018, False

YAMAUCHI Shigeo, 日本天文学会春季年会, 銀河中心北側に位置する角状拡散軟 X 線放射, Mar. 2018, False

YAMAUCHI Shigeo, 天の川銀河研究会2017, 銀河リッジ X 線放射の中性鉄輝線における低エネルギー宇宙線の寄与, Oct. 2017, False

YAMAUCHI Shigeo, 日本天文学会秋季年会, 分子雲と相互作用している超新星残骸における宇宙線起源の中性鉄輝線探査, Sep. 2017, False

YAMAUCHI Shigeo, 日本天文学会春季年会, 鉄 K 殻輝線精密診断による銀河系拡散 X 線放射の起源, Mar. 2017, False

YAMAUCHI Shigeo, 日本天文学会春季年会, 銀河系バルジ領域における拡散 X 線強度と近赤外星数面密度の空間分布比較, Mar. 2017, False

YAMAUCHI Shigeo, 日本天文学会春季年会, X線天文衛星「ひとみ (ASTRO-H)」搭載硬 X 線望遠鏡 (HXT) の軌道上 での性能評価II, Mar. 2017, False

YAMAUCHI Shigeo, 日本天文学会春季年会, すざく衛星を用いた超新星残骸 W49B の再結合優勢プラズマの観測, Mar. 2017, False

YAMAUCHI Shigeo, 日本天文学会春季年会, 超新星残骸における MeV 陽子起源の中性鉄輝線放射, Mar. 2017, False

YAMAUCHI Shigeo, 日本天文学会秋季年会, X線天文衛星「ひとみ (ASTRO-H)」搭載硬 X 線望遠鏡 (HXT) の軌道上 での性能評価, Sep. 2016, False

YAMAUCHI Shigeo, 日本物理学会2016年秋季年会, 「ひとみ(ASTRO-H)」衛星：硬X線望遠鏡の軌道上での性能評価, Sep. 2016, False

YAMAUCHI Shigeo, 日本天文学会春季年会, 銀河リッジX線放射の中性鉄輝線における宇宙線の寄与, Mar. 2016, False

YAMAUCHI Shigeo, 日本物理学会第71回年次大会, ASTRO-H衛星搭載X線望遠鏡について, Mar. 2016, False

YAMAUCHI Shigeo, 日本天文学会秋季年会, すざく衛星による渦巻銀河M101の観測, Sep. 2015, False

YAMAUCHI Shigeo, 日本天文学会秋季年会, 銀河リッジX線放射の6.4 keV輝線, Sep. 2015, False

YAMAUCHI Shigeo, 日本天文学会春季年会, ASTRO-H搭載 硬X線望遠鏡(HXT)の開発の現状 VII, Mar. 2014, False

YAMAUCHI Shigeo, 日本天文学会春季年会, Mixed-Morphology型超新星残骸Kes 27のプラズマの電離状態について, Mar. 2014, False

YAMAUCHI Shigeo, 日本物理学会, ASTRO-H 搭載X線望遠鏡の開発の現状, Mar. 2014, False

YAMAUCHI Shigeo; Yamauchi, S, Suzaku-MAXI 2014 -- Expanding the Frontiers of the X-ray Universe --, Suzaku Observation of the Spiral Galaxy M101, Feb. 2014, True

YAMAUCHI Shigeo; Sawada, M; Koyama, K; Bamba, A; Yamauchi, S; Fukui, Y, Suzaku-MAXI 2014 -- Expanding the Frontiers of the X-ray Universe --, A Suzaku comprehensive study of recombining plasma in SNRs, Feb. 2014, True

YAMAUCHI Shigeo; Minami, S; Yamauchi, S; Koyama, K, Suzaku-MAXI 2014 -- Expanding the Frontiers of the X-ray Universe --, Mixed-morphology supernova remnant Kes27 with Suzaku, Feb. 2014, True

YAMAUCHI Shigeo, 日本天文学会秋季年会, 超新星残骸G348.5+0.1のX線放射について, Sep. 2013, False

YAMAUCHI Shigeo, 日本物理学会, ASTRO-H衛星搭載用X線望遠鏡(HXT,SXT)の開発II, Sep. 2013, False

YAMAUCHI Shigeo, 日本天文学会春季年会, XMM-Newton衛星を用いた低表面輝度銀河団A1631のエントロピー測定, Mar. 2013, False

YAMAUCHI Shigeo, 日本天文学会春季年会, ASTRO-H搭載 硬X線望遠鏡(HXT)の開発の現状 V, Mar. 2013, False

YAMAUCHI Shigeo, 日本天文学会春季年会, 過電離プラズマモデルを用いた超新星残骸W49Bのスペクトル解析, Mar. 2013, False

YAMAUCHI Shigeo, 日本物理学会, ASTRO-H搭載硬X線望遠鏡(HXT)の開発, Sep. 2012, False

YAMAUCHI Shigeo, 日本天文学会秋季年会, ASTRO-H搭載 硬X線望遠鏡(HXT)の開発の現状 V, Sep. 2012, False

YAMAUCHI Shigeo, 日本天文学会春季年会, ASTRO-H搭載 硬X線望遠鏡(HXT)の開発の現状 IV, Mar. 2012, False

YAMAUCHI Shigeo, 日本天文学会春季年会, Galactic diffuse X-ray emissionの鉄輝線について, Mar. 2012, False

YAMAUCHI Shigeo, 日本天文学会春季年会, すざく衛星による低表面輝度銀河団A76のエントロピー測定, Mar. 2012, False

YAMAUCHI Shigeo, 日本天文学会春季年会, すざく衛星による超新星残骸 G355.6-0.0 の高温プラズマの観測, Mar. 2012, False

YAMAUCHI Shigeo, 日本天文学会秋季年会, すざく衛星による天の川銀河の背後に潜む銀河団の発見, Sep. 2011, False

YAMAUCHI Shigeo, 日本天文学会秋季年会, ASTRO-H搭載 硬X線望遠鏡(HXT)の開発の現状 III, Sep. 2011, False

YAMAUCHI Shigeo, 日本天文学会春季年会(年会での発表成立), ASTRO-H搭載 硬X線望遠鏡(HXT)の開発の現状 II, Mar. 2011, False

YAMAUCHI Shigeo; Yamauchi, S, International Workshop "The First Year of MAXI: Monitoring Variable X-Ray Sources", Ginga Observation of a Recurrent Soft X-Ray Transient Source 1RXS J170930.2-263927, Nov. 2010, True

YAMAUCHI Shigeo; Takahashi, T, SPIE Astronomical Instrumentation "Space Telescopes and Instrumentation 2010: Ultraviolet to Gamma Ray", The ASTRO-H Mission, Jun. 2010, True

YAMAUCHI Shigeo; Awaki, H; Kunieda, H; Furuzawa, A; Haba, Y; Iizuka, R; Ishibashi, K; Ishida, M; Itoh, M; Kosaka, T; Maeda, Y; Matsumoto, H; Miyazawa, T; Mori, H; Namba, Y; Ogasaka, Y; Ogi, K; Okajima, T; Suzuki, Y; Tamura, K; Tawara, Y; Uesugi, K; Yamashita, K; Yamauchi, S, SPIE Astronomical Instrumentation "Space Telescopes and Instrumentation 2010: Ultraviolet to Gamma Ray", Hard X-ray telescope to be onboard ASTRO-H, Jun. 2010, True

YAMAUCHI Shigeo; Mori, H; Haba, Y; Miyazawa, T; Furuzawa, A; Tawara, Y; Kunieda, H; Yamauchi, S; Awaki, H; Ishida, M; Maeda, Y; Bamba, A; Iizuka, R; Okajima, T; Mushotzky, R, SPIE Astronomical Instrumentation "Space Telescopes and Instrumentation 2010: Ultraviolet to Gamma Ray", Current status of the pre-collimator development for the ASTRO-H X-ray telescopes, Jun. 2010, True

YAMAUCHI Shigeo, 日本天文学会春季年会, XMM-Newton衛星とすざく衛星による銀河団候補天体の発見, Mar. 2010, False

YAMAUCHI Shigeo, 日本天文学会春季年会, Astro-H/XRTと硬X線望遠鏡ハウジングの開発の現状, Mar. 2010, False

YAMAUCHI Shigeo, 日本天文学会春季年会, Astro-H搭載X線望遠鏡のプリコリメータ開発の現状, Mar. 2010, False

YAMAUCHI Shigeo, 日本物理学会第65回年次大会, 次期宇宙X線衛星Astro-H搭載用X線望遠鏡の開発, Mar. 2010, False

YAMAUCHI Shigeo, 日本天文学会秋季年会, すざく衛星による超新星残骸G12.0-0.1の観測, Sep. 2009

YAMAUCHI Shigeo, 日本天文学会秋季年会, AstroH塔載、硬X線望遠鏡用光線追跡シミュレーターの開発, Sep. 2009

YAMAUCHI Shigeo; Ebisawa, K; Yamauchi, S; Tanaka, Y; Koyama, K, International conference "The Energetic Cosmos: from Suzaku to Astro-H", Suzaku Observation of Galactic Ridge and Bulge, Jul. 2009, True

YAMAUCHI Shigeo; Tanaka, Y; Yamauchi, S, International conference "The Energetic Cosmos: from Suzaku to Astro-H", Characteristics of Energy Spectrum of the Galactic Ridge X-Ray Emission, Jul. 2009, True

YAMAUCHI Shigeo; Yamauchi, S, International X-ray Observatory (IXO) Open Science Meeting, SNR Science, Jul. 2009, True

YAMAUCHI Shigeo; Nakajima, H; Tsuru, T; Nobukawa, M; Matsumoto, H; Koyama, K; Murakami, H; Yamauchi, S, International conference "The Energetic Cosmos: from Suzaku to Astro-H", X-Ray Reflection Nebulae with Large Equivalent Widths of Neutral Iron K-alpha Line in the Sgr C Region, Jun. 2009, True

YAMAUCHI Shigeo; Yamauchi, S, International conference "The Energetic Cosmos: from Suzaku to Astro-H", Suzaku Observation of the Supernova Remnant G344.7-0.1, Jun. 2009, True

YAMAUCHI Shigeo; Morii, M; Kawai, N; Terada, Y; Takahashi, H; Arimoto, M; Kitamoto, S; Kohmura, T; Shibazaki, N; Yamauchi, S; Kobayashi, N; Tanaka, Y. T; Terada, H, International conference "The Energetic Cosmos: from Suzaku to Astro-H", Suzaku Spectroscopy of a Magnetar 1E 1841-045 and Search for NIR Pulsation of a Magnetar 4U 0142+61, Jun. 2009, True

YAMAUCHI Shigeo, 日本天文学会秋季年会, すざく衛星による超新星残骸 G344.7-0.1 の観測(II), Sep. 2008, False

YAMAUCHI Shigeo, 日本天文学会春季年会, すざく衛星による超新星残骸 G344.7-0.1 の観測, Mar. 2008, False

YAMAUCHI Shigeo, 日本天文学会春季年会, 「すざく」による Anomalous X-ray Pulsar 1E 1841?045 の観測 (II), Mar. 2008, False

YAMAUCHI Shigeo, 日本物理学会秋季年会, 「すざく」衛星による銀河中心拡散 X 線放射の観測, Sep. 2007, False

YAMAUCHI Shigeo, 日本天文学会秋季年会, 「ぎんが」衛星データアーカイブスによる銀河中心方向に位置するトランジェント天体の発見, Sep. 2007, False

YAMAUCHI Shigeo, 日本天文学会秋季年会, 超新星残骸 CTB37A 領域からの熱的 X 線放射とパルサー星雲候補天体の発見, Sep. 2007, False

YAMAUCHI Shigeo, 日本天文学会秋季年会, すざくによる銀河中心領域からの広がった硬 X 線放射の発見, Sep. 2007, False

森岡夏未; 上塚奈々絵; 山内茂雄; 信川久実子, 日本天文学会春季年会, XMM-Newton 衛星による系外惑星 HD 189733b の大気密度分布の調査, Mar. 2021, 16 Mar. 2021, 19 Mar. 2021

鈴木那梨; 山内茂雄; 信川久実子; 信川正順, 日本天文学会春季年会, X 線天文衛星「すざく」を用いた超新星残骸 W49B の再結合優勢プラズマの 観測, Oral presentation, Mar. 2021, 16 Mar. 2021, 19 Mar. 2021

信川久実子; 山内茂雄; 信川正順; 佐野栄俊; 柘植紀節; 藤 田裕, 日本天文学会春季年会, 30 Doradus 複合領域における中性鉄輝線の調査 (2), Mar. 2020, 16 Mar. 2020, 19 Mar. 2020

森岡夏未; 山内茂雄, 日本天文学会春季年会, HD189733b の X 線、紫外線によるトランジット観測, Mar. 2020, 16 Mar. 2020, 19 Mar. 2020

金丸善朗; 佐藤仁; 高木駿亨; 寺田裕大; 住田知也; 森浩二; 齋藤真梨子; 信川久実子; 山内 茂雄; 迫聖; 信川正順; 田中孝明; 内田裕之; 天野雄輝; 尾近洸行; 鶴 剛; 花岡真帆; 米山友景; 岡崎貴樹; 朝倉一統; 佐久間翔太郎; 服部兼吾; 石倉彩美; 野田博 文; 林田清; 松本浩典; 冨田洋; 樫村晶; 中嶋大; 卜部夕希; 平賀純子; 村上弘志; 内山秀樹; 山内誠; 廿日出勇; 幸村孝由; 萩野浩一; 小林翔悟; 山岡和貴; 堂谷忠靖; 尾崎正伸; ISAS; JAXA; 常深博; 他 XRISM; チーム, 日本天文学会春季年会, XRISM 搭載軟 X 線撮像装置 Xtend のフライト用 CCD 素子の性能評価, Mar. 2020, 16 Mar. 2020, 19 Mar. 2020

齋藤真梨子; 信川久実子; 山内茂雄; 信川正順; 迫聖; 金丸善朗; 佐藤 仁; 高木駿亨; 森浩二; 山内誠; 廿日出勇; 林田清; 野田博文; 松本浩典; 米山友景; 花岡真帆; 岡崎貴樹; 朝倉一統; 佐久間翔太郎; 服部兼吾; 石倉彩美; 常深博; 冨田洋; 田中孝明; 内田裕之; 天野雄輝; 尾近洸行; 鶴剛; 樫村晶; 中嶋大; 村上弘志; 内山秀樹; 幸村孝由; 萩野浩一; 小林翔悟; 山岡和貴; 卜部夕希乃; 平賀純子; 他 XRISM; チーム, 日本天文学会春季年会, XRISM 搭載 Xtend の新しい CTI 補正方法の検討, Mar. 2020, 16 Mar. 2020, 19 Mar. 2020

迫聖; 信川正順; 齋藤真梨子; 信川久実子; 山内茂雄; 佐藤仁; 金丸善 朗; 高木駿亨; 西岡祐介; 森浩二; 林田清; 冨田洋 (ISAS; JAXA; 尾近洸行; 天 野雄輝; 田中孝明; 内田裕之; 鶴剛; 樫村晶; 中嶋大; 米山友景; 岡崎貴 樹; 朝倉一統; 花岡真帆; 服部兼吾; 佐久間翔太郎; 野田博文; 松本浩典; 常深博; 村上弘志; 内山秀樹; 山内誠; 廿日出勇; 幸村孝由; 萩野浩一; 小林翔悟; 山岡和貴; 卜部夕希乃; 平賀純子; 尾崎正伸; 堂谷忠靖; 他 XRISM; チーム, 日本天文学会春季年会, XRISM 搭載 Xtend の Grade-dependent offset 補正の調査, Mar. 2020, 16 Mar. 2020, 19 Mar. 2020

山内茂雄; 大屋萌; 信川久実子, 日本天文学会秋季年会, 超新星残骸候補 G189.6+3.3 の X 線スペクトル, Sep. 2019, 11 Sep. 2019, 13 Sep. 2019

嶋口愛加; 信川久実子; 山内茂雄, 日本天文学会秋季年会, すざく衛星による W51 領域からの中性鉄輝線の発見 (2), Sep. 2019, 11 Sep. 2019, 13 Sep. 2019

佐藤仁; 金丸善朗; 高木駿亨; 寺田裕大; 住田知也; 森浩二; 林田清; 冨田洋; 田中孝明; 内田裕之; 天野雄輝; 鶴剛; 中嶋大; 野田博文; 松 本浩典; 常深博; 村上弘志; 信川正順; 信川久実子; 齋藤真 梨子; 山内茂雄; 内山秀樹; 山内誠; 廿日出勇; 幸村孝由; 萩野 浩一; 小林翔悟; 山岡和貴; 平賀純子; 他 XRISM; チーム, 日本天文学会秋季年会, X 線分光撮像衛星 XRISM 搭載軟 X 線撮像装置 Xtend のフライト用 X 線 CCD 素子の性能評価 (1): 電荷転送効率評価, Sep. 2019, 11 Sep. 2019, 13 Sep. 2019

高木駿亨; 金丸善朗; 佐藤仁; 寺田裕大; 住田知也; 森浩二; 林田清; 冨田洋; 田中孝明; 内田裕之; 天野雄輝; 鶴剛; 中嶋大; 野田博文; 松 本浩典; 常深博; 村上弘志; 信川正順; 信川久実子; 齋藤真 梨子; 山内茂雄; 内山秀樹; 山内誠; 廿日出勇; 幸村孝由; 萩野 浩一; 小林翔悟; 山岡和貴; 平賀純子; 他 XRISM; チーム, 日本天文学会秋季年会, X 線分光撮像衛星 XRISM 搭載軟 X 線撮像装置 Xtend のフライト用 X 線 CCD 素子の性能評価 (2): 軟 X 線応答評価, Sep. 2019, 11 Sep. 2019, 13 Sep. 2019

齋藤真梨子; 信川久実子; 山内茂雄; 信川正順; 迫聖; 金丸善朗; 佐藤 仁; 高木駿亨; 森浩二; 山内誠; 廿日出勇; 林田清; 野田博文; 松本浩典; 米山友景; 岡崎貴 樹; 朝 倉一統; 常深博; 冨田洋; 田中孝明; 内田裕之; 天野雄輝; 鶴剛; 中嶋大; 村上弘志; 内山秀樹; 幸村孝由; 萩野浩一; 小林翔 悟; 山岡和貴; 平賀純子; 他 XRISM; チーム, 日本天文学会秋季年会, X 線分光撮像衛星 XRISM 搭載軟 X 線撮像装置 Xtend のフライト用 X 線 CCD 素子の性能評価: Grade 間における波高値の違いの評価, Sep. 2019, 11 Sep. 2019, 13 Sep. 2019

永友健太郎; 廿日出勇; 林田清; 冨田洋; 森浩二; 田中孝明; 内田裕之; 鶴剛; 中嶋大; 野田博文; 松本浩典; 常深博; 村上弘志; 信川正順; 信川久実子; 山内茂雄; 内山秀樹; 山内誠; 幸村孝由; 萩野浩一; 小林翔悟; 山岡和 貴; 平賀純子; 堂谷忠靖; 尾崎正伸; 他 XRISM; チーム, 日本天文学会秋季年会, X 線分光撮像衛星 XRISM 搭載軟 X 線撮像装置 Xtend の X 線シールド, Sep. 2019, 11 Sep. 2019, 13 Sep. 2019

高橋弘充; 田代信; 寺田幸功; 信川正順; 水野恒史; 宇野 伸一郎; 久保田あや; 中澤知洋; 渡辺伸; 飯塚亮; 佐藤理江; 林克洋; 米山友景; Chris Baluta; 海老沢研; 江口智士; 深澤泰司; 加藤颯; 勝田哲; 北口貴雄; 小高裕和; 大野雅功; 太田直美; 阪間美南; 佐藤諒平; 志達めぐみ; 菅原泰晴; 丹波翼; 谷本敦; 寺島雄一; 坪井陽子; 内田和海; 内田悠介; 内山秀樹; 山内茂雄, 日本天文学会春季年会, X 線分光撮像衛星 XRISM の観測データ処理とその準備状況, Oral presentation, 05 Mar. 2022

林克洋; 田代信; 寺田幸功; 高橋弘充; 信川正順; 水野恒史; 宇野伸一郎; 久保田あや; 中澤知洋; 渡辺伸; 飯 塚亮; 佐藤理江; 米山友景; Chris Baluta; 海老沢研; 江口智士; 深澤泰司; 加藤颯; 勝田哲; 北口貴雄; 小高裕和; 大野雅功; 太田直美; 阪間美南; 佐藤諒平; 志達めぐみ; 菅原 泰晴; 丹波翼; 谷本敦; 寺島雄一; 坪井陽子; 内田和海; 内田悠介; 内山秀樹; 山内茂雄, 日本天文学会春季年会, X 線分光撮像衛星 XRISM の科学運用準備の現状, Oral presentation, 05 Mar. 2022

火物瑠偉; 信川正順; 山内茂雄; 信川久実子; 鈴木那梨, 日本天文学会春季年会, 超新星残骸 W28 の過電離プラズマにおける初期状態の観測的研究, 03 Mar. 2022

信川久実子; 信川正順; 山内茂雄, 日本天文学会春季年会, Swift とすざくによる MAXI J1421−613 のダスト散乱エコーの観測, Oral presentation, 02 Mar. 2022

山本久美子; 山内茂雄; 信川正順; 信川久実子, 日本天文学会秋季年会, すざく衛星による銀河面拡散 X 線放射のスペクトル解析, Oral presentation, 15 Sep. 2021

鈴木那梨; 山内茂雄; 信川久実子; 信川正順; 火物瑠偉, 日本天文学会秋季年会, 再結合優勢プラズマを持つ超新星残骸 W49B の空間構造の調査, Oral presentation, 14 Sep. 2021

藤重朝妃; 山内茂雄; 信川正順; 信川久実子, 日本天文学会秋季年会, X 線天文衛星「すざく」を用いた超新星残骸 G352.7−0.1 におけるプラズマの 空間構造の調査, Oral presentation, 14 Sep. 2021

林克洋; 田代信; 寺田幸功; 高橋弘充; 信川正順; 水野恒史; 宇野伸一郎; 久保田あや; 中澤知洋; 渡辺伸; 飯塚亮; 佐藤理江; 米山友景; 吉田鉄生; Chris Baluta; 海老沢研; 江口智士; 深澤泰司; 橋口葵; 勝田哲; 北口貴雄; 小高裕和; 大野雅功; 太田直美; 阪間美南; 阪本菜月; 志達めぐみ; 塩入匠; 丹波翼; 谷本敦; 寺島雄一; 坪井陽子; 内田和海; 内田悠介; 内山秀樹; 山田智史; 山内茂雄, 日本物理学会 2023 年春季大会, X 線分光撮像衛星 XRISM の科学運用に向けての模擬試験, Mar. 2023

内田悠介; 田代信; 寺田幸功; 高橋弘充; 信川正順; 水野恒史; 宇野伸一郎; 久保田あや; 中澤知洋; 渡辺 伸; 飯塚亮; 佐藤理江; 米山友景; 吉田鉄生; Chris Baluta; 海老沢研; 江口智士; 深澤泰司; 橋口葵; 林 克洋; 勝田哲; 北口貴雄; 小高裕和; 大野雅功; 太田直美; 阪間美南; 阪本菜月; 志達めぐみ; 塩入匠; 丹 波翼; 谷本敦; 寺島雄一; 坪井陽子; 内田和海; 内山秀樹; 山田智史; 山内茂雄, 日本物理学会 2023 年春季大会, X 線分光撮像衛星 XRISM の科学運用への準備状況, Mar. 2023

山田智史; 田代信; 寺田幸功; 高橋弘充; 信川正順; 水野恒史; 宇野伸一郎; 久保田あや; 中澤知洋; 渡辺伸; 飯塚 亮; 佐藤理江; 林克洋; 米山友景; 吉田鉄生; Chris Baluta; 海老沢研; 江口智士; 深澤泰司; 橋口葵; 勝田哲; 北口貴雄; 小高裕和; 大野雅功; 太田直美; 阪間美南; 阪本菜月; 志達めぐみ; 塩入匠; 丹波翼; 谷本敦; 寺島雄一; 坪井陽子; 内田和海; 内田悠介; 内山秀樹; 山内茂雄, 日本天文学会春季年会, X 線分光撮像衛星 XRISM の観測データ処理ツールの開発状況, Mar. 2023

林克洋; 田代信; 寺田幸功; 高橋弘充; 信川正順; 水野恒史; 宇野伸一郎; 久保田あや; 中澤知洋; 渡辺 伸; 飯塚亮; 佐藤理江; 米山友景; 吉田鉄生; Chris Baluta; 海老沢研; 江口智士; 深澤泰司; 橋口葵; 勝田哲; 北口貴雄; 小高裕和; 大野雅功; 太田直美; 阪間美南; 阪本菜月; 志達めぐみ; 塩入匠; 丹波翼; 谷本敦; 寺島雄一; 坪井陽子; 内田和海; 内田悠介; 内山秀樹; 山田智史; 山内茂雄, 日本天文学会春季年会, X 線分光撮像衛星 XRISM の科学運用に向けての模擬試験, Mar. 2023

米山友景; 田代信; 寺田幸功; 高橋弘充; 信川正順; 水野恒史; 宇野伸一郎; 久保田あや; 中澤知洋; 渡 辺伸; 飯塚亮; 佐藤理江; 林克洋; 吉田鉄生; Chris Baluta; 海老沢研; 江口智士; 深澤泰司; 橋口葵; 勝田哲; 北口貴雄; 小高裕和; 大野雅功; 太田直美; 阪間美南; 阪本菜月; 志達めぐみ; 塩入匠; 丹波翼; 谷本敦; 寺島雄一; 坪井陽子; 内田和海; 内田悠介; 内山秀樹; 山田智史; 山内茂雄, 日本天文学会春季年会, X 線分光撮像衛星 XRISM の科学運用準備の現状 (2), Mar. 2023

安樂由実子; 山内茂雄, 日本天文学会春季年会, 銀河面方向に位置する銀河団を用いた星間物質量の推定, Mar. 2023

藤重朝妃; 山内茂雄; 信川正順; 信川久実子, 日本天文学会春季年会, すざく衛星による超新星残骸 Kes 27 のプラズマの空間構造の調査, Mar. 2023

鈴木那梨; 山内茂雄; 信川久実子; 信川正順, 日本天文学会春季年会, 再結合優勢プラズマを持つ超新星残骸 W49B における中性鉄輝線の探査, Mar. 2023

古瀬愛実; 鈴木那梨; 山内茂雄; 信川正順; 信川久実子; 森川朋美, 日本天文学会春季年会, 超新星残骸 G346.6 - 0.2 のスペクトル解析と再結合優勢プラズマの形成過程, Mar. 2023

森川朋美; 信川久実子; 小沼将天; 信川正順; 山内茂雄; 佐治重孝; 松本浩典, 日本天文学会秋季年会, 超新星残骸における低エネルギー宇宙線起源の中性鉄輝線の探査, Sep. 2022, 13 Sep. 2022, 15 Sep. 2022

山本久美子; 山内茂雄; 信川正順; 信川久実子; 内山秀樹, 日本天文学会秋季年会, すざく衛星による銀河面拡散 X 線放射の空間構造の調査, Sep. 2022, 13 Sep. 2022, 15 Sep. 2022

小沼将天; 信川久実子; 信川正順; 山内茂雄, 日本天文学会秋季年会, X 線天文衛星「すざく」による超新星残骸 3C 400.2 のプラズマ調査, Sep. 2022

鈴木那梨; 山内茂雄; 信川久実子; 信川正順, 日本天文学会秋季年会, 再結合優勢プラズマを持つ超新星残骸 W49B の空間的な温度構造と進化過程, Sep. 2022

藤重朝妃; 山内茂雄; 信川正順; 信川久実子, 日本天文学会秋季年会, すざく衛星による超新星残骸 G344.7-0.1 の空間構造の調査, Sep. 2022

森川朋美; 信川久実子; 小沼将天; 信川正順; 山内茂雄; 内山秀樹; 松本浩典, 日本天文学会2023年秋季年会, 超新星残骸 G304.6+0.1 と G346.6−0.2 からの中性鉄輝線放射の起源, 21 Sep. 2023, 20 Sep. 2023, 22 Sep. 2023

鈴木那梨; 山内茂雄; 信川久実子; 信川正順; 勝田哲, 日本天文学会2023年秋季年会, 超新星残骸 W49B における電荷交換反応の検証, 21 Sep. 2023, 20 Sep. 2023, 22 Sep. 2023

小沼将天; 信川久実子; 信川正順; 山内茂雄; 内山秀樹, 日本天文学会2023年秋季年会, X 線天文衛星すざくによる超新星残骸 3C 400.2 のプラズマ状態と近傍 X 線未同定天体の調査, 21 Sep. 2023, 20 Sep. 2023, 22 Sep. 2023

正嶋大和; 信川正順; 信川久実子; 竹内清香; 山内茂雄; 内山秀樹, 日本天文学会2023年秋季年会, X 線天文衛星すざくによる超新星残骸 G82.2+5.3 の観測, 21 Sep. 2023, 20 Sep. 2023, 22 Sep. 2023

吉野有咲; 山内茂雄, 日本天文学会2023年秋季年会, すざく衛星による超コンパクト X 線連星 4U 1543−624 のスペクトル観測, 21 Sep. 2023, 20 Sep. 2023, 22 Sep. 2023

林克洋; 田代信; 寺田幸功; 高橋弘充; 信川正順; 水野恒史; 宇野伸一郎; 久保田あや; 中澤知洋; 渡辺伸; 飯塚 亮; 佐藤理江; 星野晶夫; 吉田鉄生; 小川翔司; 金丸善朗; Chris Baluta; 海老沢研; 江口智士; 小高裕和; 勝田哲; 北口貴雄; 新居田祐基; 太田直美; 阪本菜月; 志達めぐみ; 塩入匠; 白木 天音; 谷本敦; 寺島雄一; 坪井陽子; 内田和海; 内田 悠介; 内山秀樹; 山田智史; 山内茂雄; 米山友景, 日本天文学会2023年秋季年会, X 線分光撮像衛星 XRISM の科学運用準備の現状 (3), 20 Sep. 2023, 20 Sep. 2023, 22 Sep. 2023

2000年度日本天文学会研究奨励賞, 日本天文学会, Mar. 2001

1999年度日本天文学会欧文研究報告論文賞, 日本天文学会, Apr. 2000

01 Apr. 2021, 31 Mar. 2024, Coinvestigator

Grant-in-Aid for Scientific Research (C), 2006, 2008, 18540228, Broad-Band X-Ray Observations of the Galactic Diffuse X-Ray Emission, YAMAUCHI Shigeo, Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research, Iwate University, 1800000, 1500000, 300000, X線天文衛星により取得した観測データの解析により、銀河面X線放射に電離の進んでいない鉄からの輝線を発見し、数千万度の温度の希薄な高温プラズマガスからの放射に加えて非熱的放射が存在することを明らかにした。鉄輝線を中心に、X線スペクトルの特徴より起源について考察を行った。また、銀河中心、銀河円盤領域の観測中に見つかったトランジェント天体、銀河面X線放射との関連が深いと考えられる超新星残骸の解析も行い、これらの特徴、性質を明らかにした。, kaken

Grant-in-Aid for Scientific Research (C), 2003, 2005, 15540225, Research of Galactic Diffuse X-Ray Sources, YAMAUCHI Shigeo, Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research, Iwate University, 1600000, 1600000, In order to investigate the diffuse X-ray emission located in the galactic plane and the galactic bulge region, we analyzed data obtained in scanning and pointing observations with the Ginga satellite. We made an intensity map of a K-line from a He-like iron in an optically thin hot plasma, and confirmed that the optically thin hot plasma has a wide distribution along the galactic plane. The intensity map in the 10-20 keV energy band is similar to that of the iron K-line, and hence the non-thermal X-rays are also found in the large part of the Galaxy. We analyzed ASCA data of supernova remnants detected in the X-ray band for the first time. The X-ray spectrum of G344.7-0.1 exhibited an X-ray emission from an optically thin hot plasma with a temperature of about 9 million K and a strong emission line from a low-ionized iron. The ASCA Galactic plane survey discovered several unidentified diffuse hard X-ray sources. We carried out detailed analysis using data of follow-up observations and a radio intensity map and found that the diffuse sources are candidates for supernova remnants emitting non-thermal X-rays. We analyzed data of a transient X-ray source discovered in the galactic center region with Ginga. We determined its sky position. The X-ray spectra obtained in the several occasions were well represented by either a comptonized blackbody model or a two-temperature blackbody model and the spectral parameters did not change significantly., kaken

特定領域研究, 2003, 2004, 15037201, 銀河面サーベイ観測にもとづくブラックホール候補天体の研究, 山内 茂雄, 日本学術振興会, 科学研究費助成事業, 岩手大学, 1400000, 1400000, ぎんが衛星を用いた銀河面サーベイ観測のデータを解析し、ブラックホール候補天体の探査を行った。その結果、じょうぎ座の方向に柔らかいX線スペクトルをもつ天体を発見した。X線カタログと照合したが、本研究で求めた誤差領域は大きいため、明確な対応天体は特定できなかった。新天体である可能性が高い。同じ領域はぎんが衛星で複数回観測を行っているが、この天体が検出できたのは1988年4月のみである。またアメリカのRXTE衛星の銀河面サーベイ観測でも対応する天体はみられない。これらのことから、トランジェント天体であると結論した。X線スペクトルは、ブラックホール天体がハイステートの時期に見せるX線スペクトルと同様の温度が600万度の降着円盤からの放射モデルでよく説明できる。X線スペクトルの特徴、トランジェント天体であることはブラックホール候補天体のもつ性質と矛盾しないことがわかった。この結果については論文にまとめ、投稿した。 銀河円盤領域にはたくさんのX線天体が存在する。銀河中心方向に見つかったトランジェント天体は、存在する位置とX線スペクトルのおおよその形から考えて、小質量星と中性子星との連星系である可能性が高い。そのX線スペクトルをこの種類の天体で適用される降着円盤からと中性子星表面からの放射のモデルで合わせてみると、降着円盤からの放射の温度は典型的な値に比べ高くなることがわかった。これはブラックホール候補天体のvery high stateにおける傾向とよく似ている。ブラックホール候補天体の場合と同じような高温のプラズマによるコンプトン散乱の効果も考慮し、スペクトル解析を行った。, kaken

特定領域研究(A), 1998, 2001, 10147103, X線によるマゼラン星雲等の星形成領域の研究, 小山 勝二; 山内 茂雄; 伊藤 真之; 長瀬 文昭; 北本 俊二, 日本学術振興会, 科学研究費助成事業, 京都大学, 77500000, 77500000, ASCA衛星とチャンドラ衛星(公募観測)をもちいたマゼラン雲のX線天体種族の系統的研究、星形成活動と関連する課題の研究、X線検出技術開発のプロジェクトを完成させた。 今年度の成果は: 小マゼラン雲のX線源を系統的に研究し、X線パルサー10個以上発見を含む、種族分類を終了した。最終報告の投稿論文を製作中である。 銀河系内、星形成領域の最高感度の観測を実行し、蛇使い座暗黒星雲から後期原始星(class1)と褐色わい星からのX線を始めて系統的に研究し、その発生機構を明らかにした。 オリオン分子雲中の前期原始星(class0)からのX線を発見した。また一角獣座の分子雲中から大質量前主系列星からのX線を始めて検出した。 世界最高レベルに近い性能をもつX線CCDの開発、製作に成功した。 またX線イベント抽出方法を開発し、実質的な高いエネルギー感度を向上を実現した。, kaken

奨励研究(A), 1997, 1998, 09740167, 天文衛星を用いた超新星残骸の研究, 山内 茂雄, 日本学術振興会, 科学研究費助成事業, 岩手大学, 1700000, 1700000, 前年度に引き続き、現在私たちが「あすか」衛星を利用して進めている、硬X線銀河面サーベイ観測(ASCA Galactic Plane Survey)によって得られたデータの解析を行った。 銀河円盤上に存在し、電波領域で検出されている超新星残骸のX線スペクトルを調べた。これらの多くはX線スペクトルに硅素、硫黄などからの輝線が明確に検出され、超新星爆発の際に生じた衝撃波によって加熱生成された高温ガスからの放射であると結論できたが、一部の超新星残骸では、X線スペクトルに明確な輝線を検出することができなかった。観測時間が短いため、データ統計の不十分さによって輝線が検出できなかったという可能性も考えられるが、非熱的放射である可能性も考えられる。 また、サーベイ観測で、円盤状、アーク状、リング状の構造を持つ、拡がった天体がいくつか検出できた。これらは既知の天体に同定されず、新超新星残骸である可能性が高い。X線スペクトルは通常の超新星残骸に比べ、硬X線の割合が多く、また、明確な輝線を示さないことから、非熱的放射を持つ超新星残骸である可能性が考えられる。これらの性質を明らかにするために、長時間追観測を提案した。 最近の観測で、超新星残骸には非熱的放射が付随していることが示されてきた。銀河面に沿って拡がる拡散成分には、輝線を伴う高温ガス成分の他に、硬X線からガンマ線領域にわたって伸びる非熱的成分が存在することが指摘されているが、この成分は超新星残骸の集合として説明できる可能性がでてきた。今後、両成分について系統的に観測、研究を続けていく予定である。, kaken

Grant-in-Aid for international Scientific Research, 1996, 1998, 08044103, X-ray Astronomy Study with the ASCA Satellite, NAGASE Fumiaki; TANAKA Yasuo; ISHIDA Manabu; TAKAHASHI Tadayiki; MITSUDA Kazuhisa; INOUE Hajime, Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research, The Institute of Space and Astronautical Science, 9100000, 9100000, The purpose of this project is to perform observations and operations of ASCA in a collaboration between Japan and the United States of America, and to obtain scientific results from the X-ray observations on the X-ray binaries including compact objects, supernova remnants, active galactic nuclei, clusters of galaxies and the cosmic X-ray background. ASCA is the fourth Japanese X-ray satellite which was constructed in a collaboration between Japan and the U.S.A., and it was launched on February 20, 1993. The results of this project are summarized below : (1)We had national meetings and Japan-U.S.A.international meetings every year to select observation targets from the proposals, and discuss the organization of observation and operation of the satellite. (2)We examined the performance of the instruments onboard the satellite and provided the calibration database of the response of the instruments, including a time-dependent degradation of the performance of instruments. (3)We continuosly updated various software programs for data analysis, and produced an archival database for the convenience of international users. (4)We analyzed data from our own observations, and discussed the results with our partner country. These scientific results were presented at the international conferences and were published in academic journals. (5)All of the archival data were released to the scientists around the world with well-organized formats when the period of exclusive use by the owners expired. Because of the support by this grant-in-aid, we were able to perform well the ASCA observations and operations under the collaboration between Japan and the U.S.A.We obtained remarkable scientific results from the ASCA observations in various fields of X-ray astronomy., kaken

奨励研究(A), 1996, 1996, 08740167, X線観測による原始星の研究, 山内 茂雄, 日本学術振興会, 科学研究費助成事業, 岩手大学, 900000, 900000, 本研究の目的は、原始星、T Tauri型星など前主系列星をX線で観測し、星形成の初期段階におけるX線放射メカニズムおよび活動性の進化を統一的に調べることである。このためさまざまな種類の天体を比較検討する必要があり、本年度は大質量星も形成されているオリオン星雲と小質星が生成されているカメレオン座分子雲IIのデータ解析を行い、結果を検討した。オリオン星雲では、原始星の存在している領域が密集領域であるため、あすか衛星の角分解能では、原始星候補からのX線を特定することができなかった。しかし、それ以外に多数のT Tauri型星が検出でき、これらが高温のプラズマガスからの放射として説明できることがわかった。カメレオン座分子雲IIの観測では全部で8つの天体を検出することができた。しかし、この領域に存在する原始星候補からは有為なX線を検出することができなっかった。原始星候補からのX線が検出できなかったカメレオン座分子雲IIと検出された蛇使い座分子雲、南の冠座分子雲との違いについて今後検討を進めたい。また、オリオン星雲とカメレオン座分子雲IIに存在するT Tauri型星の特徴を比較した結果、オリオン星雲の天体はカメレオン座分子雲IIの天体に比べて、ガスの温度が高温になる傾向があり、0.7-10keVのエネルギー領域の光度も大きいことがわかった。温度の違いは何が原因であるのか、今後サンプルを増やし、検討を行いたい。 この他、中質量の前主系列星であるHerbig Ae型星の観測も行い、X線スペクトルの解析から高温ガスからの放射であること示した。高速の星風や表面磁場を持たないと考えられているこの種類の天体で、観測されたような高温のプラズマガスを生成するメカニズムについて検討を行った。, kaken

重点領域研究, 1996, 1996, 08212202, 銀河系内高温ガスと関連天体の研究, 山内 茂雄, 日本学術振興会, 科学研究費助成事業, 岩手大学, 900000, 900000, 1.銀河系内高温ガスの研究 銀河面サ-ペイ観測のデータを用いて、Galactic Ridge Emissionの特徴と銀河系内の分布を調べた。銀河円盤上の各観測点で得られたGalactic Ridge Emissionのスペクトルは、いずれも0.7-1keVと7-9keV程度の2つの温度を持つ電離非平衡段階にある高温ガスとして再現できることがわかった。このことは銀河円盤全体にわたってほぼ同じ物理状態の高温ガスが分布していることを示す。また、銀河円盤に沿った方向の高温ガスの分布を調べてみると、高温成分は銀河中心に対してほぼ対称な分布であるのに対し、低温成分は銀河中心に対して非対称になっていることがわかった。一方、銀河円盤に垂直な方向のスペクトルの変化を調べた結果、銀河面から離れると、低温成分についてはそれほど変化しないが、高温成分は急激に減少し、鉄輝線を含まない硬いスペクトルを持つ成分に変わっていく傾向があることがわかった。 2.超新星残骸の研究 Galactic Ridge Emissionと関連する天体である超新星残骸に注目し、銀河面サーベイ観測のデータの解析を進めた。電波サーベイでは検出されていなかった超新星残骸G347.5-0.5を検出し、その解析からシェル部分には輝線が見られず、非熱的放射であることを明らかにした。これは超新星残骸で粒子加速が行われている可能性を示唆するもので、SN1006につづき2番目のサンプルである。また、これまでに電波サーベイでは検出されていたが、X線では検出されていなかった超新星残骸を多数検出し、これらのX線領域での特徴を調べた。, kaken

奨励研究(A), 1995, 1995, 07740178, X線観測による星形成領域の磁気的活動性の研究, 山内 茂雄, 日本学術振興会, 科学研究費助成事業, 岩手大学, 1000000, 1000000, 本年度は主として活発な星形成領域の一つであるオリオン星雲領域の「あすか」衛星により取得したデータの解析を行った。観測領域には明るい天体の他に強度が弱い天体や「あすか」では点源に分離できない領域が含まれている。星形成領域に存在する天体の特徴を明確にするため、観測領域を複数の天体を含んだ4つの大きな領域に分割してスペクトルを集積し、この統計の良い平均のスペクトルの特徴を調べてみた。いずれの領域も1温度の高温プラズマガスモデルでは説明できず、少なくとも2温度のモデルが必要であることがわかった。2温度で合わせた場合の高温成分の温度は3×10^7K以上となる。 次に領域毎の平均スペクトルと個々の天体のスペクトルを比較するため、検出された天体のうち統計の良いものについてスペクトルを調べてみた。その結果、いずれの天体も10^7K以上の高温成分が必要であること、統計の良いものには、領域毎のスペクトルと同様、少なくとも2温度が必用なものがあることがわかった。 観測を行った時期には個々の天体からフレアのような活動性は観測できなかった。若い天体はフレアのような突発的な活動性のみならず、小さなフレアが表面全体で起こっていることも含む比較的定常的な活動性も伴っていることになる。 今後は他の波長の結果との比較や、オリオン星雲領域以外の星形成領域の結果との比較を行い、星形成領域における磁気的活動性の統一的な理解を目指す。, kaken

重点領域研究, 1995, 1995, 07222202, X線観測による銀河系内高温ガスの研究, 山内 茂雄, 日本学術振興会, 科学研究費助成事業, 岩手大学, 1000000, 1000000, 銀河系内高温ガスの起源を調べるため、本年度は「あすか」衛星で取得した銀河円盤領域のデータの解析を行い、「ぎんが」衛星では明確にできなかったGalactic Ridge Emission(銀河系内高温ガス)の小さなスケールの構造を調べた。得られたイメージには点源や数分角程度のサイズの強度むらが見られるが、これら点源、強度むらの強度は非常に弱く、Galactic Ridge Emissionの大部分は検出した点源よりも暗い天体(2×10^<33>erg s^<-1>以下)、あるいは一様に拡がった輻射であると結論できる。また、視野ごとの強度のばらつきからもGalactic Ridge Emissionを点源の集合体として説明する場合、一天体あたりの光度は10^<34>erg s^<-1>以下でなければならないことを結論づけた。 これまでの観測結果を用いて、Galactic Ridge Emissionの起源となりうる天体を検討した。「あすか」衛星以前の観測結果からGalactic Ridge Emissionの実体を担う天体は中性子星や白色わい星を含む連星系や主系列星などではなく、比較的小さいサイズの広がりを持つ若い超新星残骸や星形成領域が候補として考えられてきた。しかし、「あすか」衛星により新たに得られた一点源あたりの光度とガスの電離度の制限は通常の若い超新星残骸や星形成領域をも候補から除外することになり、性質の良く調べられた天体の単純な重ね合わせで説明することは難しいということが分かった。 Galactic Ridge Emissionの特徴が明らかになるにつれて、その実体を担う天体はより特殊なものである可能性が高まっている。今後、銀河面サーベイ観測を実行し、高温ガスの特徴が銀河系内の場所によりどのような違いがあるのか、また、高温ガスの実体を担う新種の天体が存在しているのか等を調べていく予定である。, kaken

重点領域研究, 1994, 1994, 06233202, ラインX線を利用した銀河系内高温ガスの研究, 山内 茂雄, 日本学術振興会, 科学研究費助成事業, 岩手大学, 2000000, 2000000, 銀河円盤領域に存在するDiffuse X-ray Emissionが強度の弱い多くの点源の集まりであるのか、それとも真に拡がった輻射であるのかを観測的に明らかにするために、「あすか」衛星を用いて銀河円盤領域の撮像観測を行った。この観測中にQuiescent stateからFlare stateに移行したTransient X-ray sourceを発見した。スペクトルの特徴はX線パルサーであることを示唆するが、今回の観測ではパルス周期は検出できなかった。また、隣接する領域でも比較的明るい2点源を検出した。これらの3点源以外には強度が0.006count/s程度の暗い点源が数個程度検出されたのみで、検出できた点源の強度では視野全体の強度(0.2-0.3count/s)を説明することは難しいことが分かった。一方、ガスの物理状態を調べるために行ったX線スペクトルの解析から鉄ラインのエネルギー、強度が電離平衡状態にある宇宙組成の高温ガスから期待されるよりも低いことが分かった。これはガスが電離非平衡状態にあることを示唆する。また、「あすか」の観測からは低温の別成分の存在も考えられる。 輝線を含めたX線スペクトルの類似性、銀河系内の分布から銀河系内高温ガスの起源として考えられる超新星残骸、星形成領域を観測し、X線スペクトルの比較も行った。「てんま」「ぎんが」「あすか」衛星による観測から、いずれのスペクトルも数千万度の高温ガスからの輻射とて説明できることが分かってきた。一方、輝線の強度、エネルギーに注目すると、星形成領域の場合には輝線が弱く元素組成が宇宙組成以下の電離平衡状態にあるガスからの輻射として表現できるのに対し、超新星残骸の場合は連続成分の温度に対して輝線が強く、未だ電離平衡に達していないガスからの輻射と解釈できる。輝線の特徴から判断すると、星形成領域を銀河系内高温ガスの起源として考えることは難しいことが分かった。, kaken

Grant-in-Aid for international Scientific Research, 1992, 1994, 04044167, X-Ray Astronomy Study with the Astro-D Satellite, NAGASE Fumiaki; DOTANI Takayasu; ISHIDA Manabu; KII Tsuneo; ITOH Masayuki; MATSUOKA Masaru; SHIBAZAKI Noriaki; OHASHI Takaya; KUNIEDA Hideyo; TAWARA Yujuru; KITAMOTO Shunji; MIHARA Tatehiro; TANAKA Yasuo; CANIZARES C.; RICKER G.; TSURU Takeshi; AWAKI Hisamitsu; KAWAI Nobuyuki; YOSHIDA Atsumasa; SERLEMITSOS P.; HAYASHIDA Kiyoshi; BREON S.; EBISAWA Ken; VOLZ S.v.; KELLEY R.; HELFAND D.; MCCAMMON; TSUNEMI Hiroshi; MAKISHIMA Kazuo; MITSUDA Kazuhisa; MURAKAMI Toshiaki; KOYAMA Katsuji; YAMASHITA Koujun; OGAWARA Yoshiaki; MIYAMOTO Shigenori; MUSHOTZKY R.; MAKINO Fumiyashi; HOLT S.; INOUE Hajime, Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research, The Institute of Space and Astronautical Science, 11600000, 11600000, ASCA (ASTRO-D), the fourth X-ray astronomy satellite of ISAS,was successfully launched on February 20,1993. It carries nested thin-foil X-ray mirrors providing a large effective area over a wide energy range from 0.5 to 10keV.A set of CCD cameras and imaging gas scintillation proportional counters are placed on the focal plane. ASCA is a high-throughput imaging and spectroscopic X-ray observatory with these instruments. An extensive collaboration between Japanese and U.S.scientists has been carried out in the joint developments of the X-ray telescopes, the X-ray CCD cameras, and computer software. It is continuing in the maintenance and the in-flight calibration of the instruments, and also in the data analysis and the following scientific activities. ASCA is an X-ray astronomy observatory which is, for the first time, capable of performing imaging and spectroscopic observations simultaneously over a wide energy range 0.5-10keV.The ASCA instruments cover the most important energy band for plasma diagnostics, because all the K-lines and the K-absorption edges from oxygen through iron at various ionization stages lie within this band. The CCD camera of ASCA can resolve all major lines individually. Motion of plasma of the order or greater than 1000km/s can be measured significantly from Doppler shift of the line energies. These capabilities of ASCA allow diagnostics of accreting matter around such compact objects as neutron stars and black holes. Spatially-resolved spectroscopy with ASCA also provides powerful means for the investigations of extended plasmas in supernova remnants, galaxies, and clusters of galaxies. The key elements of ASCA are succesfully working in orbit. ASCA has already obtained several remarkable scientific results. Most of them are due to the Japan-US collaboration with the help of this International Scientific Research Program as A Grant-in Aid for Scientific Research., kaken

Grant-in-Aid for Scientific Research (C), 01 Apr. 2021, 31 Mar. 2024, 21K03615, Study of the Galactic Center Activity by Measurement of Dynamics and Plasma Diagnostics with Precise X-ray Spectroscopy, 信川 正順; 内山 秀樹; 山内 茂雄; 信川 久実子, Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research, Nara University of Education, 4160000, 3200000, 960000, 本研究課題での目的は、これまで解明されていない銀河中心拡散X線放射(GCXE)の起源を次世代のX線天文衛星XRISMを用いて観測し、構成成分を定量的に分離し、その運動を初めて測定することである。 XRISMは2022年度打ち上げ予定であり、本研究課題の研究者全員は XRISMの開発メンバーの一員でもある。2021年度は XRISMの開発を進め、観測の準備を行った。特に、観測装置の開発ではフライトモデルの製作を行い、検証試験および性能確認試験を実施した。さらにデータ較正の方法の開発も進めるとともに、実データを用いて較正データベースの準備を行った。打ち上げ後の観測データ処理システムの開発を進め、テストデータを用いた確認を実施し、問題がないことを確認した。 さらに、すざく衛星によるデータを用いて、GCXEスペクトルを構成する成分の定量分析を行った。我々が2016年に調べた結果では、5keV以上のエネルギー帯域だけであったが、全エネルギー帯域のスペクトルを用いた。その結果、X線点源や冷たいX線成分だけでは観測スペクトルの再現はできないが、それらに真に広がったプラズマ成分を加えると再現できることがわかった。そのプラズマは温度kT~1 keVの過電離状態である可能性がある。特に、これまでは温度kT~7 keVと高温であるため、銀河の重力では留めておけないことが問題だった。それよりも低温であれば、その問題は解決できるかもしれない。 また、GCXEの高温プラズマの候補の1つである超新星残骸の研究も進めた。特に通常の超新星残骸プラズマの進化では考えられない過電離状態の起源を明らかにするために、通常の電離進行型の超新星残骸も含めた複数の天体データを集めて、系統調査を行った。その結果、過電離を示す天体の電子温度は、通常天体の電子温度の時間変化と矛盾がなく、電離が促進されている可能性がわかった。, kaken

Grant-in-Aid for Scientific Research (C), 01 Apr. 2012, 31 Mar. 2016, 24540232, Study of the Galactic Diffuse X-ray Emission, YAMAUCHI SHIGEO, Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research, Nara Women's University, 2600000, 2000000, 600000, In order to investigate the origin of the Galactic diffuse X-ray emission (GDXE), we carried out a systematic study of iron K-shell lines in the Galaxy. Using intensities of three emission lines at 6.4, 6.7 and 6.97 keV, we determined the spatial distribution and equivalent width of each line for the first time. Comparing the spatial distributions and equivalent widths with those of the cataclysmic variables and flare stars, we discussed the origin of the GDXE. We found similar diffuse X-ray emission with an intense iron K-shell line in the spiral galaxy M101. We analyzed the data of supernova remnants and extended sources in the Galaxy and obtained new results of the X-ray emission., kaken

Grant-in-Aid for Scientific Research (C), 2009, 2011, 21540234, Spectral Study of the Galactic Diffuse X-Ray Emission, YAMAUCHI Shigeo, Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research, Nara Women's University, 2080000, 1600000, 480000, Using the Suzaku data observed in the Galactic center, Galactic plane, and Galactic bulge regions, I studied properties of Fe-K emission lines of the Galactic diffuse X-ray emission. The ratios of 6. 97keV/6. 7 keV in the Galactic center and the Galactic bulge regions are systematically larger than that of the Galactic plane. The observed Fe emission line cannot be reproduced by a spectral model for active star binaries and white dwarf binaries. We also studied newly discovered X-ray sources and supernova remnants., kaken