Curriculum Vitaes

Yasuharu Sugawara

  (菅原 泰晴)

Profile Information

Affiliation
Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency
Degree
理学博士(中央大学)
理学修士(中央大学)

J-GLOBAL ID
201201017168289883
researchmap Member ID
7000000018

Research Interests

 2

Papers

 27
  • Midooka, Takuya, Sugawara, Yasuharu, Ebisawa, Ken
    Monthly Notices of the Royal Astronomical Society, 484(2) 2229-2233, Apr, 2019  Peer-reviewed
    WR 125 is considered to be a colliding-wind Wolf-Rayet binary (CWWB), from which the most recent infrared flux increase was reported between 1990 and 1993. We observed the object four times from 2016 November to 2017 May with Swift and XMM-Newton, and carried out a precise X-ray spectral study for the first time. There were hardly any changes in the fluxes and spectral shapes for half a year, and the absorption-corrected luminosity was 3.0 x 10(33) erg s(-1) in the range 0.5-10.0 keV at a distance of 4.1 kpc. The hydrogen column density was higher than that expected from the interstellar absorption, and thus the X-ray spectra were probably absorbed by the Wolf-Rayet (WR) wind. The energy spectrum was successfully modelled by a collisional equilibrium plasma emission, in which both the plasma and the absorbing wind have unusual elemental abundances particular to WR stars. In 1981, the Einstein satellite clearly detected X-rays from WR 125, whereas the ROSAT satellite hardly detected X-rays in 1991, when the binary was probably around the periastron passage. We discuss possible causes for the unexpectedly low soft X-ray flux near the periastron.
  • 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, Stephane 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, 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, 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
    PUBLICATIONS OF THE ASTRONOMICAL SOCIETY OF JAPAN, 70(6), Oct 1, 2018  
    We present the results from the Hitomi Soft Gamma-ray Detector (SGD)<br /> observation of the Crab nebula. The main part of SGD is a Compton camera, which<br /> in addition to being a spectrometer, is capable of measuring polarization of<br /> gamma-ray photons. The Crab nebula is one of the brightest X-ray / gamma-ray<br /> sources on the sky, and, the only source from which polarized X-ray photons<br /> have been detected. SGD observed the Crab nebula during the initial test<br /> observation phase of Hitomi. We performed the data analysis of the SGD<br /> observation, the SGD background estimation and the SGD Monte Carlo simulations,<br /> and, successfully detected polarized gamma-ray emission from the Crab nebula<br /> with only about 5 ks exposure time. The obtained polarization fraction of the<br /> phase-integrated Crab emission (sum of pulsar and nebula emissions) is (22.1<br /> $\pm$ 10.6)% and, the polarization angle is 110.7$^o$ + 13.2 / $-$13.0$^o$ in<br /> the energy range of 60--160 keV (The errors correspond to the 1 sigma<br /> deviation). The confidence level of the polarization detection was 99.3%. The<br /> polarization angle measured by SGD is about one sigma deviation with the<br /> projected spin axis of the pulsar, 124.0$^o$ $\pm$0.1$^o$.
  • T. Kawamuro, Y. Ueda, M. Shidatsu, T. Hori, M. Morii, S. Nakahira, N. Isobe, N. Kawai, T. Mihara, M. Matsuoka, T. Morita, M. Nakajima, H. Negoro, S. Oda, T. Sakamoto, M. Serino, M. Sugizaki, A. Tanimoto, H. Tomida, Y. Tsuboi, H. Tsunemi, S. Ueno, K. Yamaoka, S. Yamada, A. Yoshida, W. Iwakiri, Y. Kawakubo, Y. Sugawara, S. Sugita, Y. Tachibana, T. Yoshii
    Astrophysical Journal, Supplement Series, 238(2), Oct, 2018  
    © 2018. The American Astronomical Society. All rights reserved.. We present the third MAXI/GSC catalog in the high Galactic latitude sky () based on the 7-year data from 2009 August 13 to 2016 July 31, complementary to that in the low Galactic latitude sky (|b| > 10°) (Hori et al. 2018). We compile 682 sources detected at significances of s D,4-10 keV ≥ 6.5 in the 4-10 keV band. A two-dimensional image fit based on the Poisson likelihood algorithm (C-statistics) is adopted for the detections and constraints on their fluxes and positions. The 4-10 keV sensitivity reaches ≈0.48 mCrab, or ≈5.9 × 10-12 erg cm-2 s-1, over half of the survey area. Compared with the 37-month Hiroi et al. (2013) catalog, which adopted a threshold of s D,4-10 keV ≥ 7, the source number increases by a factor of ∼1.4. The fluxes in the 3-4 keV and 10-20 keV bands are further estimated, and hardness ratios (HRs) are calculated using the 3-4 keV, 4-10 keV, 3-10 keV, and 10-20 keV band fluxes. We also make the 4-10 keV light curves in 1-year bins for all the sources and characterize their variabilities with an index based on a likelihood function and the excess variance. Possible counterparts are found from five major X-ray survey catalogs by Swift, Uhuru, RXTE, XMM-Newton, and ROSAT, as well as an X-ray galaxy cluster catalog (MCXC). Our catalog provides the fluxes, positions, detection significances, HRs, 1-year bin light curves, variability indices, and counterpart candidates.
  • 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
    PUBLICATIONS OF THE ASTRONOMICAL SOCIETY OF JAPAN, 70(3), Jun, 2018  Peer-reviewed
  • 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, Meng P. Chiao, Paolo S. Coppi, Elisa Costantini, Steve O' Dell, Michael DiPirro, Chris Done, Tadayasu Dotani, John Doty, Ken Ebisawa, Megan E. Eckart, Teruaki Enoto, Yuichiro Ezoe, Andrew C. Fabian, Carlo Ferrigno, Adam R. Foster, Ryuichi Fujimoto, Yasushi Fukazawa, Stefan Funk, Akihiro Furuzawa, Massimiliano Galeazzi, Luigi C. Gallo, Poshak Gandhi, Kirk Gilmore, Margherita Giustini, Andrea Goldwurm, Liyi Gu, Matteo Guainazzi, Daniel Haas, Yoshito Haba, Kouichi Hagino, Kenji Hamaguchi, Ilana M. Harrus, Isamu Hatsukade, Takayuki Hayashi, Katsuhiro Hayashi, Kiyoshi Hayashida, Jan Willem Den Herder, Junko S. Hiraga, Kazuyuki Hirose, Ann Hornschemeier, Akio Hoshino, John P. Hughes, Yuto Ichinohe, Ryo Iizuka, Hajime Inoue, Yoshiyuki Inoue, Kazunori Ishibashi, Manabu Ishida, Kumi Ishikawa, Kosei Ishimura, Yoshitaka Ishisaki, Masayuki Itoh, Masachika Iwai, Naoko Iwata, Naoko Iyomoto, Chris Jewell, Jelle Kaastra, Tim Kallman, Tsuneyoshi Kamae, Erin Kara, Jun Kataoka, Satoru Katsuda, Junichiro Katsuta, Madoka Kawaharada, Nobuyuki Kawai, Taro Kawano, Shigeo Kawasaki, Dmitry Khangulyan, Caroline A. Kilbourne, Mark Kimball
    Journal of Astronomical Telescopes, Instruments, and Systems, 4(2), Apr, 2018  Peer-reviewed
    © The Authors. 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 February 17, 2016, the spacecraft lost its function on March 26, 2016, but the commissioning phase for about a month provided valuable information on the onboard 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.

Misc.

 16
  • Y. Tsuboi, R. Sasaki, Y. Sugawara, M. Matsuoka
    Proceedings of Science, Jan 1, 2017  
    © Copyright owned by the author(s) under the terms of the Creative Commons. Since the launch in 2009 August, with the unprecedentedly high sensitivity as an all-sky X-ray monitor, MAXI has caught more than a hundred of huge flares from stars. Most of them are from low-mass, active stars (RS CVn systems, an Algol system, dMe systems, a dKe system, Young Stellar Objects). With the total radiative energy of 1034–1039ergs, the MAXI detections have broken the record of the largest flaring magnitudes in each stellar categories. The enlarged sample of intense flares has enabled us to do systematic studies in various viewpoints. One of the studies is the discovery of a universal correlation between the flare duration and the intrinsic X-ray luminosity, which holds for 5 and 12 orders of magnitude in the duration and LX, respectively (Tsuboi et al. 2016). Here, we review the studies of stellar flares obtained with MAXI.
  • Christopher M, P. Russell, Michael F. Corcoran, Jorge Cuadra, Stanley P. Owocki, Q. Daniel Wang, Kenji Hamaguchi, Yasuharu Sugawara, Andrew M. T. Pollock, Timothy R. Kallman
    Nov 4, 2015  
    Colliding Wolf-Rayet (WR) winds produce thermal X-ray emission widely<br /> observed by X-ray telescopes. In wide WR+O binaries, such as WR 140, the X-ray<br /> flux is tied to the orbital phase, and is a direct probe of the winds&#039;<br /> properties. In the Galactic center, $\sim$30 WRs orbit the super massive black<br /> hole (SMBH) within $\sim$10&quot;, leading to a smorgasbord of wind-wind collisions.<br /> To model the X-ray emission of WR 140 and the Galactic center, we perform 3D<br /> hydrodynamic simulations to trace the complex gaseous flows, and then carry out<br /> 3D radiative transfer calculations to compute the variable X-ray spectra. The<br /> model WR 140 RXTE light curve matches the data well for all phases except the<br /> X-ray minimum associated with periastron, while the model spectra agree with<br /> the RXTE hardness ratio and the shape of the Suzaku observations throughout the<br /> orbit. The Galactic center model of the Chandra flux and spectral shape match<br /> well in the region r$&lt;$3&quot;, but the model flux falls off too rapidly beyond this<br /> radius.
  • Sugawara, Yasuharu, Tsuboi, Yohko, Maeda, Yoshitomo
    Suzaku-MAXI 2014: Expanding the Frontiers of the X-ray Universe, pp.pp220-221, Sep, 2014  
  • Russell, Christopher M. P, Okazaki, Atsuo T, Owocki, Stanley P, Corcoran, Michael F, Hamaguchi, Kenji, Sugawara, Yasuharu
    Suzaku-MAXI 2014: Expanding the Frontiers of the X-ray Universe, pp.pp208-209, Sep, 2014  
  • Kawagoe, A, Tsuboi, Y, Sugawara, Y, Maehara, Y, Hashimoto, O, Honda, S, Morihana, K, Iizuka, R, Higa, M, Usui, R, Negoro, H
    Suzaku-MAXI 2014: Expanding the Frontiers of the X-ray Universe, pp.pp164-165, Sep, 2014  

Presentations

 68

Teaching Experience

 2

Research Projects

 3