Hiromitsu Takahashi - for The PoGOLite Collaboration

Hiromitsu Takahashi
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Hiromitsu Takahashi
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for The PoGOLite Collaboration
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High Energy Astrophysical Phenomena (18)
 
Astrophysics (17)
 
Instrumentation and Methods for Astrophysics (14)
 
Cosmology and Nongalactic Astrophysics (4)
 
Solar and Stellar Astrophysics (3)
 
Astrophysics of Galaxies (2)
 
Physics - Instrumentation and Detectors (2)

Publications Authored By Hiromitsu Takahashi

2016Oct
Affiliations: 1SGD team, 2SGD team, 3SGD team, 4SGD team, 5SGD team, 6SGD team, 7SGD team, 8SGD team, 9SGD team, 10SGD team, 11SGD team, 12SGD team, 13SGD team, 14SGD team, 15SGD team, 16SGD team, 17SGD team, 18SGD team, 19SGD team, 20SGD team

Gamma-ray polarization offers a unique probes into the geometry of the gamma-ray emission process in celestial objects. The Soft Gamma-ray Detector (SGD) onboard the X-ray observatory Hitomi is a Si/CdTe Compton camera and is expected to be an excellent polarimeter, as well as a highly sensitive spectrometer due to its good angular coverage and resolution for Compton scattering. A beam test of the final-prototype for the SGD Compton camera was conducted to demonstrate its polarimetric capability and to verify and calibrate the Monte Carlo simulation of the instrument. Read More

2016Jul
Authors: Hitomi Collaboration, Felix A. Aharonian, Hiroki Akamatsu, Fumie Akimoto, Steven W. Allen, Lorella Angelini, Keith A. Arnaud, Marc Audard, Hisamitsu Awaki, Magnus Axelsson, Aya Bamba, Marshall W. Bautz, Roger D. Blandford, Laura W. Brenneman, Gregory V. Brown, Esra Bulbul, Edward M. Cackett, Maria Chernyakova, Meng P. Chiao, Paolo 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 Harrus, Isamu Hatsukade, Katsuhiro Hayashi, Takayuki Hayashi, Kiyoshi Hayashida, Junko Hiraga, Ann E. Hornschemeier, Akio Hoshino, John P. Hughes, Yuto Ichinohe, Ryo Iizuka, Hajime Inoue, Shota Inoue, Yoshiyuki Inoue, Kazunori Ishibashi, Manabu Ishida, Kumi Ishikawa, Yoshitaka Ishisaki, Masayuki Itoh, Naoko Iyomoto, Jelle S. Kaastra, Timothy Kallman, Tuneyoshi Kamae, Erin Kara, Jun Kataoka, Satoru Katsuda, Junichiro Katsuta, Madoka Kawaharada, Nobuyuki Kawai, Richard L. Kelley, Dmitry Khangulyan, Caroline A. Kilbourne, Ashley L. King, Takao Kitaguchi, Shunji Kitamoto, Tetsu Kitayama, Takayoshi Kohmura, Motohide Kokubun, Shu Koyama, Katsuji Koyama, Peter Kretschmar, Hans A. Krimm, Aya Kubota, Hideyo Kunieda, Philippe Laurent, Francois Lebrun, Shiu-Hang Lee, Maurice Leutenegger, Olivier Limousin, Michael Loewenstein, Knox S. Long, David Lumb, Grzegorz M. 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, Harvey Moseley, Koji Mukai, Hiroshi Murakami, Toshio Murakami, Richard F. Mushotzky, Takao Nakagawa, Hiroshi Nakajima, Takeshi Nakamori, Toshio Nakano, Shinya Nakashima, Kazuhiro Nakazawa, Kumiko Nobukawa, Masayoshi Nobukawa, Hirofumi Noda, Masaharu Nomachi, Steve L. 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 D. Ramsey, Christopher S. Reynolds, Helen R. Russell, Samar Safi-Harb, Shinya Saito, Kazuhiro Sakai, Hiroaki Sameshima, 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 E. 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, C. Meg 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, Atsumasa Yoshida, Irina Zhuravleva, Abderahmen Zoghbi

High-resolution X-ray spectroscopy with Hitomi was expected to resolve the origin of the faint unidentified E=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. Read More

How black holes accrete surrounding matter is a fundamental, yet unsolved question in astrophysics. It is generally believed that matter is absorbed into black holes via accretion disks, the state of which depends primarily on the mass-accretion rate. When this rate approaches the critical rate (the Eddington limit), thermal instability is supposed to occur in the inner disc, causing repetitive patterns of large-amplitude X-ray variability (oscillations) on timescales of minutes to hours. Read More

2016Jul
Authors: Hitomi Collaboration, 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 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 Yamaok, 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 of cosmological parameters and a host of astrophysical processes. Knowledge of the dynamics of the pervasive hot gas, which dominates in mass over stars in a cluster, is a crucial missing ingredient. Read More

PoGOLite is a balloon-borne hard X-ray polarimeter dedicated to the study of point sources. Compton scattered events are registered using an array of plastic scintillator units to determine the polarisation of incident X-rays in the energy range 20 - 240 keV. In 2013, a near circumpolar balloon flight of 14 days duration was completed after launch from Esrange, Sweden, resulting in a measurement of the linear polarisation of the Crab emission. Read More

The evolved, massive highly eccentric binary system, eta Carinae, underwent a periastron passage in the summer of 2014. We obtained two coordinated X-ray observations with XMM-Newton and NuSTAR during the elevated X-ray flux state and just before the X-ray minimum flux state around this passage. These NuSTAR observations clearly detected X-ray emission associated with eta Car extending up to ~50 keV for the first time. Read More

2015Nov
Authors: Fabio Acero, Markus Ackermann, Marco Ajello, Luca Baldini, Jean Ballet, Guido Barbiellini, Denis Bastieri, Ronaldo Bellazzini, E. Bissaldi, Roger Blandford, E. D. Bloom, Raffaella Bonino, Eugenio Bottacini, J. Bregeon, Philippe Bruel, Rolf Buehler, S. Buson, G. A. Caliandro, Rob A. Cameron, R Caputo, Micaela Caragiulo, Patrizia A. Caraveo, Jean Marc Casandjian, Elisabetta Cavazzuti, Claudia Cecchi, A. Chekhtman, J. Chiang, G. Chiaro, Stefano Ciprini, R. Claus, J. M. Cohen, Johann Cohen-Tanugi, L. R. Cominsky, B. Condon, Jan Conrad, S. Cutini, F. D'Ammando, A. Angelis, F. Palma, Rachele Desiante, S. W. Digel, L. Venere, Persis S Drell, Alex Drlica-Wagner, C. Favuzzi, E. C. Ferrara, Anna Franckowiak, Prof. Yasushi Fukazawa, Prof. Stefan Funk, P. Fusco, Fabio Gargano, Dario Gasparrini, Nicola Giglietto, Paolo Giommi, Francesco Giordano, Marcello Giroletti, Tom Glanzman, Gary Godfrey, G A. Gomez-Vargas, I. A. Grenier, M. -H. Grondin, L. Guillemot, Sylvain Guiriec, M Gustafsson, D. Hadasch, A. K. Harding, M. Hayashida, Elizabeth Hays, J. W. Hewitt, A. B. Hill, Deirdre Horan, X. Hou, Giulia Iafrate, Tobias Jogler, G. J'ohannesson, Anthony S. Johnson, T. Kamae, Hideaki Katagiri, Prof. Jun Kataoka, Junichiro Katsuta, Matthew Kerr, J. Knodlseder, Prof. Dale Kocevski, M. Kuss, Helene Laffon, J. Lande, S. Larsson, Luca Latronico, Marianne Lemoine-Goumard, J. Li, L. Li, Francesco Longo, Francesco Loparco, Michael N. Lovellette, Pasquale Lubrano, J. Magill, S. Maldera, Martino Marelli, Michael Mayer, M. N. Mazziotta, Peter F. Michelson, Warit Mitthumsiri, Tsunefumi Mizuno, Alexander A. Moiseev, Maria Elena Monzani, E. Moretti, Aldo Morselli, Igor V. Moskalenko, Prof. Simona Murgia, Prof. Rodrigo Nemmen, Eric Nuss, Takashi Ohsugi, Nicola Omodei, Monica Orienti, Elena Orlando, Jonathan F. Ormes, David Paneque, J. S. Perkins, Melissa Pesce-Rollins, Prof. Vahe' Petrosian, Frederic Piron, Giovanna Pivato, Troy Porter, S. Rain`o, Riccardo Rando, Massimiliano Razzano, Soebur Razzaque, Anita Reimer, Prof. Olaf Reimer, Matthieu Renaud, Thierry Reposeur, Mr. Romain Rousseau, P. M. Parkinson, J. Schmid, A. Schulz, C. Sgr`o, Eric J Siskind, Francesca Spada, Gloria Spandre, Paolo Spinelli, Andrew W. Strong, Daniel Suson, Hiro Tajima, Hiromitsu Takahashi, T. Tanaka, Jana B. Thayer, D. J. Thompson, L. Tibaldo, Omar Tibolla, Prof. Diego F. Torres, Gino Tosti, Eleonora Troja, Yasunobu Uchiyama, G. Vianello, B. Wells, Kent Wood, M. Wood, Manal Yassine, Stephan Zimmer

To uniformly determine the properties of supernova remnants (SNRs) at high energies, we have developed the first systematic survey at energies from 1 to 100 GeV using data from the Fermi Large Area Telescope. Based on the spatial overlap of sources detected at GeV energies with SNRs known from radio surveys, we classify 30 sources as likely GeV SNRs. We also report 14 marginal associations and 245 flux upper limits. Read More

The Soft Gamma-ray Detector (SGD), to be deployed onboard the {\it ASTRO-H} satellite, has been developed to provide the highest sensitivity observations of celestial sources in the energy band of 60-600~keV by employing a detector concept which uses a Compton camera whose field-of-view is restricted by a BGO shield to a few degree (narrow-FOV Compton camera). In this concept, the background from outside the FOV can be heavily suppressed by constraining the incident direction of the gamma ray reconstructed by the Compton camera to be consistent with the narrow FOV. We, for the first time, demonstrate the validity of the concept using background data taken during the thermal vacuum test and the low-temperature environment test of the flight model of SGD on ground. Read More

2014Dec
Authors: 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 Blandford, Kevin Boyce, Laura Brenneman, Greg Brown, 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, Stefan Funk, Akihiro Furuzawa, Massimiliano Galeazzi, Luigi Gallo, Poshak Gandhi, Kirk Gilmore, Matteo Guainazzi, Daniel Haas, Yoshito Haba, Kenji Hamaguchi, Atsushi Harayama, Isamu Hatsukade, Takayuki Hayashi, Katsuhiro 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 Ito, 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 Khangulyan, Caroline Kilbourne, Mark Kimball, Masashi Kimura, Shunji Kitamoto, Tetsu Kitayama, Takayoshi Kohmura, Motohide Kokubun, Saori Konami, Tatsuro Kosaka, Alex Koujelev, Katsuji Koyama, Hans Krimm, Aya Kubota, Hideyo Kunieda, Stephanie LaMassa, Philippe Laurent, Franccois Lebrun, Maurice Leutenegger, Olivier Limousin, Michael Loewenstein, Knox Long, David Lumb, Grzegorz Madejski, Yoshitomo Maeda, Kazuo Makishima, Maxim Markevitch, Candace Masters, Hironori Matsumoto, Kyoko Matsushita, Dan McCammon, Daniel Mcguinness, Brian McNamara, Joseph Miko, Jon Miller, Eric Miller, Shin Mineshige, Kenji Minesugi, Ikuyuki Mitsuishi, Takuya Miyazawa, Tsunefumi Mizuno, Koji Mori, Hideyuki Mori, Franco Moroso, Theodore Muench, Koji Mukai, Hiroshi Murakami, Toshio Murakami, Richard Mushotzky, Housei Nagano, Ryo Nagino, Takao Nakagawa, Hiroshi Nakajima, Takeshi Nakamori, Shinya Nakashima, Kazuhiro Nakazawa, Yoshiharu Namba, Chikara Natsukari, Yusuke Nishioka, Masayoshi Nobukawa, Hirofumi Noda, Masaharu Nomachi, Steve O' Dell, Hirokazu Odaka, Hiroyuki Ogawa, Mina Ogawa, Keiji Ogi, Takaya Ohashi, Masanori Ohno, Masayuki Ohta, Takashi Okajima, Atsushi Okamoto, Tsuyoshi Okazaki, Naomi Ota, Masanobu Ozaki, Frits Paerels, St'ephane Paltani, Arvind Parmar, Robert Petre, Ciro Pinto, Martin Pohl, James Pontius, F. Scott Porter, Katja Pottschmidt, Brian Ramsey, Rubens Reis, Christopher Reynolds, Claudio Ricci, Helen Russell, Samar Safi-Harb, Shinya Saito, Shin-ichiro Sakai, Hiroaki Sameshima, Goro Sato, Yoichi Sato, Kosuke Sato, Rie Sato, Makoto Sawada, Peter Serlemitsos, Hiromi Seta, Yasuko Shibano, Maki Shida, Takanobu Shimada, Keisuke Shinozaki, Peter Shirron, Aurora Simionescu, Cynthia Simmons, Randall Smith, Gary Sneiderman, Yang Soong, Lukasz Stawarz, Yasuharu Sugawara, Hiroyuki Sugita, Satoshi Sugita, Andrew Szymkowiak, Hiroyasu Tajima, Hiromitsu Takahashi, Hiroaki Takahashi, Shin-ichiro Takeda, Yoh Takei, Toru Tamagawa, Takayuki Tamura, Keisuke 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, Yasunobu Uchiyama, Hideki Uchiyama, Yoshihiro Ueda, Shutaro Ueda, Shiro Ueno, Shinichiro Uno, Meg Urry, Eugenio Ursino, Cor de Vries, Atsushi Wada, Shin Watanabe, Tomomi Watanabe, Norbert Werner, Nicholas White, Dan Wilkins, Takahiro Yamada, Shinya Yamada, Hiroya Yamaguchi, Kazutaka Yamaoka, Noriko Yamasaki, Makoto Yamauchi, Shigeo Yamauchi, Tahir Yaqoob, Yoichi Yatsu, Daisuke Yonetoku, Atsumasa Yoshida, Takayuki Yuasa, Irina Zhuravleva, Abderahmen Zoghbi, John ZuHone

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 Delta E < 7 eV of the micro-calorimeter, will enable a wide variety of important science themes to be pursued. Read More

The Suzaku X-ray observatory monitored the supermassive binary system Eta Carinae 10 times during the whole 5.5 year orbital cycle between 2005-2011. This series of observations presents the first long-term monitoring of this enigmatic system in the extremely hard X-ray band between 15-40 keV. Read More

PoGOLino is a balloon-borne scintillator-based experiment developed to study the largely unexplored high altitude neutron environment at high geomagnetic latitudes. The instrument comprises two detectors that make use of LiCAF, a novel neutron sensitive scintillator, sandwiched by BGO crystals for background reduction. The experiment was launched on March 20th 2013 from the Esrange Space Centre, Northern Sweden (geomagnetic latitude of $65^\circ$), for a three hour flight during which the instrument took data up to an altitude of 30. Read More

PoGOLino is a scintillator-based neutron detector. Its main purpose is to provide data on the neutron flux in the upper stratosphere at high latitudes at thermal and nonthermal energies for the PoGOLite instrument. PoGOLite is a balloon borne hard X-ray polarimeter for which the main source of background stems from high energy neutrons. Read More

The neutron-star Low-Mass X-ray Binary Aquila X-1 was observed by Suzaku for seven times, from 2007 September 28 to October 30. The observations successfully traced an outburst decay in which the source luminosity decreased almost monotonically from $\sim 10^{37}$ erg s$^{-1}$ to $\sim 10^{34}$ erg s$^{-1}$, by $\sim 3$ orders of magnitude. To investigate luminosity-dependent changes in the accretion geometry, five of the seven data sets with a typical exposure of $\sim 18$ ks each were analyzed; the other two were utilized in a previous work \citep{Sakurai2012}. Read More

We observed IGR J16194-2810 in the low/hard state with the Suzaku X-ray satellite in 2009. The source is a Symbiotic X-ray Binary (SyXB) classified as a category of a Low-Mass X-ray Binary (LMXB), since the system is composed of an M-type giant and probably a neutron star (NS). We detected the 0. Read More

3C 66A is an intermediate-frequency-peaked BL Lac object detected by the Large Area Telescope onboard the Fermi Gamma-ray Space Telescope. We present a study of the long-term variations of this blazar seen over 2 years at GeV energies with Fermi and in the optical (flux and polarization) and near infrared with the Kanata telescope. In 2008, the first year of the study, we find a correlation between the gamma-ray flux and the measurements taken with the Kanata telescope. Read More

2012Nov
Affiliations: 1for The PoGOLite Collaboration, 2for The PoGOLite Collaboration, 3for The PoGOLite Collaboration, 4for The PoGOLite Collaboration, 5for The PoGOLite Collaboration, 6for The PoGOLite Collaboration, 7for The PoGOLite Collaboration, 8for The PoGOLite Collaboration, 9for The PoGOLite Collaboration, 10for The PoGOLite Collaboration, 11for The PoGOLite Collaboration

PoGOLite is a hard X-ray polarimeter operating in the 25-100 keV energy band. The instrument design is optimised for the observation of compact astrophysical sources. Observations are conducted from a stabilised stratospheric balloon platform at an altitude of approximately 40 km. Read More

2012Oct
Authors: Tadayuki Takahashi, Kazuhisa Mitsuda, Richard Kelley, Henri AartsFelix 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, 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 Iwata, Naoko Iyomoto, Jelle Kaastra, Timothy Kallman, Tuneyoshi Kamae, Jun Kataoka, Satoru Katsuda, Hajime Kawahara, Madoka Kawaharada, Nobuyuki Kawai, Shigeo Kawasaki, Dmitry Khangaluyan, Caroline Kilbourne, Masashi Kimura, Kenzo Kinugasa, Shunji Kitamoto, Tetsu Kitayama, Takayoshi Kohmura, Motohide Kokubun, Tatsuro Kosaka, Alex Koujelev, Katsuji Koyama, Hans Krimm, Aya Kubota, Hideyo Kunieda, Stephanie LaMassa, Philippe Laurent, Francois Lebrun, Maurice Leutenegger, Olivier Limousin, Michael Loewenstein, Knox Long, David Lumb, Grzegorz Madejski, Yoshitomo Maeda, Kazuo Makishima, Genevieve Marchand, Maxim Markevitch, Hironori Matsumoto, Kyoko Matsushita, Dan McCammon, Brian McNamara, Jon Miller, Eric Miller, Shin Mineshige, Kenji Minesugi, Ikuyuki Mitsuishi, Takuya Miyazawa, Tsunefumi Mizuno, Hideyuki Mori, Koji Mori, Koji Mukai, Toshio Murakami, Hiroshi Murakami, Richard Mushotzky, Housei Nagano, Ryo Nagino, Takao Nakagawa, Hiroshi Nakajima, Takeshi Nakamori, Kazuhiro Nakazawa, Yoshiharu Namba, Chikara Natsukari, Yusuke Nishioka, Masayoshi Nobukawa, Masaharu Nomachi, Steve O' Dell, Hirokazu Odaka, Hiroyuki Ogawa, Mina Ogawa, Keiji Ogi, Takaya Ohashi, Masanori Ohno, Masayuki Ohta, Takashi Okajima, Atsushi Okamoto, Tsuyoshi Okazaki, Naomi Ota, Masanobu Ozaki, Frits Paerels, Stephane Paltani, Arvind Parmar, Robert Petre, Martin Pohl, F. Scott Porter, Brian Ramsey, Rubens Reis, Christopher Reynolds, Helen Russell, Samar Safi-Harb, Shin-ichiro Sakai, Hiroaki Sameshima, Jeremy Sanders, Goro Sato, Rie Sato, Yoichi Sato, Kosuke Sato, Makoto Sawada, Peter Serlemitsos, Hiromi Seta, Yasuko Shibano, Maki Shida, Takanobu Shimada, Keisuke Shinozaki, Peter Shirron, Aurora Simionescu, Cynthia Simmons, Randall Smith, Gary Sneiderman, Yang Soong, Lukasz Stawarz, Yasuharu Sugawara, Hiroyuki Sugita, Satoshi Sugita, Andrew Szymkowiak, Hiroyasu Tajima, Hiromitsu Takahashi, Shin-ichiro Takeda, Yoh Takei, Toru Tamagawa, Takayuki Tamura, Keisuke Tamura, Takaaki Tanaka, Yasuo Tanaka, Makoto Tashiro, Yuzuru Tawara, Yukikatsu Terada, Yuichi Terashima, Francesco Tombesi, Hiroshi Tomida, Yoko Tsuboi, Masahiro Tsujimoto, Hiroshi Tsunemi, Takeshi Tsuru, Hiroyuki Uchida, Yasunobu Uchiyama, Hideki Uchiyama, Yoshihiro Ueda, Shiro Ueno, Shinichiro Uno, Meg Urry, Eugenio Ursino, Cor de Vries, Atsushi Wada, Shin Watanabe, Norbert Werner, Nicholas White, Takahiro Yamada, Shinya Yamada, Hiroya Yamaguchi, Noriko Yamasaki, Shigeo Yamauchi, Makoto Yamauchi, Yoichi Yatsu, Daisuke Yonetoku, Atsumasa Yoshida, Takayuki Yuasa

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 via a suite of four instruments, covering a very wide energy range, from 0.3 keV to 600 keV. Read More

We present the result of a systematic study of pileup phenomena seen in the X-ray Imaging Spectrometer, an X-ray CCD instrument, onboard the Suzaku observatory. Using a data set of observed sources in a wide range of brightness and spectral hardness, we characterized the pileup fraction, spectral hardening, and grade migration as a function of observed count rate in a frame per pixel. Using the pileup fraction as a measure of the degree of pileup, we found that the relative spectral hardening (the hardness ratio normalized to the intrinsic spectral hardness), branching ratio of split events, and that of detached events increase monotonically as the pileup fraction increases, despite the variety of brightness and hardness of the sample sources. Read More

Improvements of in-orbit calibration of GSO scintillators in the Hard X-ray Detector on board Suzaku are reported. To resolve an apparent change of the energy scale of GSO which appeared across the launch for unknown reasons, consistent and thorough re-analyses of both pre-launch and in-orbit data have been performed. With laboratory experiments using spare hardware, the pulse height offset, corresponding to zero energy input, was found to change by ~0. Read More

From 2005 to 2009, 25 observations of Cyg X-1 were performed with Suzaku, achieving a total exposure of 446 ks. In all observations, the source was found in the low/hard state, while the 1.5--12. Read More

To investigate the physics of mass accretion onto weakly-magnetized neutron stars, 95 archival RXTE datasets of an atoll source 4U 1608-522, acquired over 1996-2004 in so-called upper-banana state, were analyzed. The object meantime exhibited 3-30 keV luminosity in the range of <~ 10^35 - 4 x 10^37 erg s^-1, assuming a distance of 3.6 kpc. Read More

X-ray and near-infrared ($J$-$H$-$K_{\rm s}$) observations of the Galactic black hole binary GX 339--4 in the low/hard state were performed with Suzaku and IRSF in 2009 March. The spectrum in the 0.5--300 keV band is dominated by thermal Comptonization of multicolor disk photons, with a small contribution from a direct disk component, indicating that the inner disk is almost fully covered by hot corona with an electron temperature of $\approx$175 keV. Read More

We systematically analyzed the high-quality Suzaku data of 88 Seyfert galaxies. We obtained a clear relation between the absorption column density and the equivalent width of the 6.4 keV line above 10$^{23}$ cm$^{-2}$, suggesting a wide-ranging column density of $10^{23-24. Read More

2010Oct
Authors: 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, Francois 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, Yujin Nakagawa, Takao Nakagawa, Hiroshi Nakajima, Takeshi Nakamori, Kazuhiro Nakazawa, Yoshiharu Namba, Masaharu Nomachi, Steve O' Dell, Hiroyuki Ogawa, Mina Ogawa, Keiji Ogi, Takaya Ohashi, Masanori Ohno, Masayuki Ohta, Takashi Okajima, Naomi Ota, Masanobu Ozaki, Frits Paerels, Stéphane Paltani, Arvind Parmer, Robert Petre, Martin Pohl, Scott Porter, Brian Ramsey, Christopher Reynolds, Shin-ichiro Sakai, Rita Sambruna, Goro Sato, Yoichi Sato, Peter Serlemitsos, Maki Shida, Takanobu Shimada, Keisuke Shinozaki, Peter Shirron, Randall Smith, Gary Sneiderman, Yang Soong, Lukasz Stawarz, Hiroyuki Sugita, Andrew Szymkowiak, Hiroyasu Tajima, Hiromitsu Takahashi, Yoh Takei, Toru Tamagawa, Takayuki Tamura, Keisuke Tamura, Takaaki Tanaka, Yasuo Tanaka, Yasuyuki Tanaka, Makoto Tashiro, Yuzuru Tawara, Yukikatsu Terada, Yuichi Terashima, Francesco Tombesi, Hiroshi Tomida, Miyako Tozuka, Yoko Tsuboi, Masahiro Tsujimoto, Hiroshi Tsunemi, Takeshi Tsuru, Hiroyuki Uchida, Yasunobu Uchiyama, Hideki Uchiyama, Yoshihiro Ueda, Shinichiro Uno, Meg Urry, Shin Watanabe, Nicholas White, Takahiro Yamada, Hiroya Yamaguchi, Kazutaka Yamaoka, Noriko Yamasaki, Makoto Yamauchi, Shigeo Yamauchi, Yoichi Yatsu, Daisuke Yonetoku, Atsumasa Yoshida

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. Read More

ASTRO-H is the next generation JAXA X-ray satellite, intended to carry instruments with broad energy coverage and exquisite energy resolution. The Soft Gamma-ray Detector (SGD) is one of ASTRO-H instruments and will feature wide energy band (40-600 keV) at a background level 10 times better than the current instruments on orbit. SGD is complimentary to ASTRO-H's Hard X-ray Imager covering the energy range of 5-80 keV. Read More

We report the results of a Suzaku observation of the anomalous X-ray pulsar (AXP) 1E 1841-045 at a center of the supernova remnant Kes 73. We confirmed that the energy-dependent spectral models obtained by the previous separate observations were also satisfied over a wide energy range from 0.4 to ~70 keV, simultaneously. Read More

We present optical and near-infrared (NIR) photometry of a classical nova, V2362 Cyg (= Nova Cygni 2006). V2362 Cyg experienced a peculiar rebrightening with a long duration from 100 to 240 d after the maximum of the nova. Our multicolor observation indicates an emergence of a pseudophotosphere with an effective temperature of 9000 K at the rebrightening maximum. Read More

We report detailed, long term near-infrared (NIR) light curves of GRS 1915+105 in 2007-2008, covering its long "soft state" for the first time. From our NIR monitoring and the X-ray data of the All Sky Monitor (ASM) onboard Rossi X-ray Timing Explorer (RXTE), we discovered that the NIR flux dropped by > 1 mag during short X-ray flares with a time-scale of days. With the termination of the soft state, the H-Ks color reddened and the anti-correlation pattern was broken. Read More

Suzaku Hard X-ray Detector (HXD) achieved the lowest background level than any other previously or currently operational missions sensitive in the energy range of 10--600 keV, by utilizing PIN photodiodes and GSO scintillators mounted in the BGO active shields to reject particle background and Compton-scattered events as much as possible. Because it does not have imaging capability nor rocking mode for the background monitor, the sensitivity is limited by the reproducibility of the non X-ray background (NXB) model. We modeled the HXD NXB, which varies with time as well as other satellites with a low-earth orbit, by utilizing several parameters, including particle monitor counts and satellite orbital/attitude information. Read More

Suzaku observation of an ultraluminous X-ray source, NGC 2403 Source 3, performed on 2006 March 16--17, is reported. The Suzaku XIS spectrum of Source 3 was described with a multi-color black-body-like emission from an optically thick accretion disk. The innermost temperature and radius of the accretion disk was measured to be $T_{\rm in} = 1. Read More

In order to elucidate origin of the 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 ~6.4 keV,~6. Read More

We report time-resolved CCD photometry of the cataclysmic variable EG Aquarii during the 2006 November outburst During the outburst, superhumps were unambiguously detected with a mean period of 0.078828(6) days, firstly classifying the object as an SU UMa-type dwarf nova. It also turned out that the outburst contained a precursor. Read More

The black-hole binary Cygnus X-1 was observed for 17 ks with the Suzaku X-ray observatory in 2005 October, while it was in a low/hard state with a 0.7-300 keV luminosity of 4.6 x 10^37 erg/s. Read More

2007Nov
Affiliations: 1ISAS/JAXA, Japan, 2ISAS/JAXA, Japan, 3Department of Physics, Tokyo Institute of Technology, Tokyo, Japan, 4ISAS/JAXA, Japan, 5ISAS/JAXA, Japan, 6Rikkyo University, Tokyo, Japan, 7RIKEN, Japan, 8University of Tokyo, Japan, 9University of Tokyo, Japan, 10Kanazawa University, Kanazawa, Japan, 11Aoyama Gakuin University, Sagamihara, Kanagawa, Japan, 12Hiroshima University, Japan, 13RIKEN, Japan, 14Aoyama Gakuin University, Sagamihara, Kanagawa, Japan
Category: Astrophysics

Suzaku TOO observation of the anomalous X-ray pulsar CXOU J164710.2-455216 was performed on 2006 September 23--24 for a net exposure of 38.8 ks. Read More

We have observed a typical Galactic plane field at (l,b) = (28.46d, -0.20d) with Suzaku for 100 ksec to carry out a precise spectral study of the Galactic Ridge X-ray Emission (GRXE). Read More

2007Nov
Affiliations: 1Saitama University Jp, 2University of Tokyo Jp, 3University of Tokyo Jp, 4Tokyo Metroporitan University Jp, 5ISAS/JAXA Jp, 6ISAS/JAXA Jp, 7ISAS/JAXA Jp, 8Kyoto University Jp, 9SRON Netherlands, 10MHI LTD Jp, 11Hiroshima University Jp, 12Stanford Univ USA, 13RIKEN Jp, 14ISAS/JAXA Jp, 15MHI LTD Jp, 16University of Tokyo Jp, 17MHI LTD Jp, 18Hiroshima University Jp, 19Kanazawa University Jp, 20University of Tokyo Jp, 21MHI LTD Jp, 22Osaka University Jp, 23MHI LTD Jp, 24ISAS/JAXA Jp, 25Hiroshima University Jp, 26Saitama University Jp, 27RIKEN Jp, 28ISAS/JAXA Jp, 29MHI LTD Jp, 30Tokyo Metroporitan University Jp, 31Kanazawa University Jp
Category: Astrophysics

The hard X-ray detector (HXD) on board the X-ray satellite Suzaku is designed to have a good timing capability with a 61 $\mu$s time resolution. In addition to detailed descriptions of the HXD timing system, results of in-orbit timing calibration and performance of the HXD are summarized. The relative accuracy of time measurements of the HXD event was confirmed to have an accuracy of $1. Read More

Five on-plane regions within +/- 0.8deg of the Galactic center were observed with the Hard X-ray Detector (HXD) and the X-ray Imaging Spectrometer (XIS) onboard 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. Read More

We describe a new balloon-borne instrument (PoGOLite) capable of detecting 10% polarisation from 200mCrab point-like sources between 25 and 80keV in one 6 hour flight. Polarisation measurements in the soft gamma-ray band are expected to provide a powerful probe into high-energy emission mechanisms as well as the distribution of magnetic fields, radiation fields and interstellar matter. At present, only exploratory polarisation measurements have been carried out in the soft gamma-ray band. Read More

2007Aug
Affiliations: 1Department of Physics, The University of Tokyo, 2Department of Physics, The University of Tokyo, 3Cosmic Radiationn Laboratory, The Institute of Physics and Chemical Research, 4Cosmic Radiationn Laboratory, The Institute of Physics and Chemical Research, 5Department of Physics, The University of Tokyo, 6Department of Physics, The University of Tokyo, 7Institute of Space and Astronautical Science, 8Institute of Space and Astronautical Science, 9Institute of Space and Astronautical Science, 10Institute of Space and Astronautical Science, 11Institute of Space and Astronautical Science, 12Department of Physics, College of Science and Technology, Nihon University, 13Department of Physical Science, Hiroshima University
Category: Astrophysics

The accretion-powered pulsar Her X-1 was observed with Suzaku twice in its main-on state, on 2005 October 5-6 and 2006 March 29-30, for a net exposure of 30.5 ks and 34.4 ks, respectively. Read More

2007Aug
Affiliations: 1ISAS/JAXA, 2Hiroshima U, 3RIKEN, 4Rutgers U, 5Hiroshima U, 6ISAS/JAXA, 7Kyoto U, 8Osaka U, 9Hiroshima U, 10Miyazaki U, 11Osaka U, 12ISAS/JAXA, 13NASA/GSFC, 14Hiroshima U, 15ISAS/JAXA, 16SLAC, 17RIKEN, 18ISAS/JAXA, 19ISAS/JAXA, 20Kyoto U
Category: Astrophysics

We report on the wide band spectra of SN 1006 as observed by Suzaku. Thermal and nonthermal emission are successfully resolved thanks to the excellent spectral response of Suzaku's X-ray CCD XIS. The nonthermal emission cannot be reproduced by a simple power-law model but needs a roll-off at 5. Read More

The Galactic black-hole binary GRO J1655$-$40 was observed with Suzaku on 2005 September 22--23, for a net exposure of 35 ks with the X-ray Imaging Spectrometer (XIS) and 20 ks with the Hard X-ray Detector (HXD). The source was detected over a broad and continuous energy range of 0.7--300 keV, with an intensity of $\sim$50 mCrab at 20 keV. Read More

2006Oct
Affiliations: 1RIKEN, 2ISAS/JAXA, 3NASA/GSFC, 4Tokyo-tech, 5Durham university, 6Kyoto University, 7Cambridge university, 8Hiroshima university, 9Hiroshima university, 10Hiroshima university, 11Aoyama university, 12University of Tokyo, RIKEN, 13University of Tokyo, 14Kogakuin university, 15NASA/GSFC
Category: Astrophysics

We present the results of six Suzaku observations of the recurrent black hole transient 4U1630-472 during its decline from outburst from February 8 to March 23 in 2006. All observations show the typical high/soft state spectral shape in the 2-50keV band, roughly described by an optically thick disk spectrum in the soft energy band plus a weak power-law tail that becomes dominant only above \~20keV. The disk temperature decreases from 1. Read More

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 provide 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. Read More

The archival XMM-Newton data of the central region of M31 were analyzed for diffuse X-ray emission. Point sources with the 0.5--10 keV luminosity exceeding $\sim 4 \times 10^{35}$ erg s$^{-1}$ were detected. Read More

2001Aug
Affiliations: 1University of Tokyo, 2University of Tokyo, 3University of Tokyo, 4University of Tokyo
Category: Astrophysics

Using ASCA, spatially integrated X-ray spectra of the central regions of M31 were studied. Data were accumulated over three different circular regions, with the radii of 3', 6' and 12', all centered on the nucleus. The spectra are relatively similar among the three regions. Read More