Hiroshi Tomida

Response function of an x-ray CCD camera on board the Astro-E satellite

We report on the x-ray response function of the x-ray CCD camera (XIS) on-board the x-ray Astronomical Satellite, Astro-E, which will be launched in February of 2000. XIS is prepared by an international team, comprising MIT, ISAS, Osaka Univ. and Kyoto Univ. We evaluate the x-ray response on the high energy band of 1.5-10 keV. Fluorescent lines from Al, Cl, Ti, Ni, Fe, Zn are irradiated on the CCD chips, and are use to construct the response function. Details of the response function; energy-scale linearity, energy resolution, quantum efficiency and etc., are given as a function of incident x-ray energies. The response function is also demonstrated to depend largely on event-selection and re-construction criteria.

ASCA observations of the supernova remnant G156.2+5.7

Abstract 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 ∼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.

Radiation damage of the x-ray CCD

We studied the proton damage effects of the x-ray CCD. We have measured x-ray CCD performances after the irradiation of energies at 2 and 9.5 MeV, and confirmed clear degradation of charge transfer efficiency (CTE) and the energy resolution. To recover degraded CTE and the energy resolution, we tried the charge injection technique, and found the improvement of CTI and the energy resolution to be one-quarter and one-third, respectively. We also estimated the energy level of the deep trap, which causes the quantization of the dark current from the radiation-damaged pixels. The trap energy level is about 0.57 eV, or near the center of forbidden band.

Disco very of an extraordinary luminous and soft X-ray transient MAXI J0158744

Mikio Morii1, Hiroshi Tomida2, Masaki Kimura2, Fumitoshi Suwa3, Hitoshi Negoro3, Motoko Serino4, Jamie A. Kennea5, Kim L. Page6, Peter A. Curran7, Frederick M. Walter8, N. Paul. M. Kuin9, Tyler Pritchard5, Satoshi Nakahira2, Kazuo Hiroi10, Ryuichi Usui1, Nobuyuki Kawai1, Julian P. Osborne6, Tatehiro Mihara4, David N. Burrows5, Neil Gehrels11, Mitsuhiro Kohama2, Masaru Matsuoka4, Motoki Nakajima12, Peter W. A. Roming13, Kousuke Sugimori1, Mutsumi Sugizaki4, Yohko Tsuboi14, Hiroshi Tsunemi15, Yoshihiro Ueda10, Shiro Ueno2 and Atsumasa Yoshida16 1Department of Physics, Tokyo Institute of Technology, Ookayama 2-12-1, Meguro-ku, Tokyo 152-8551, Japan. 2ISS Science Project Office, Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency, 2-1-1 Sengen, Tsukuba, Ibaraki 305-8505, Japan. 3Department of Physics, Nihon University, 1-8-14 Surugadai, Chiyoda, Tokyo 101-8308, Japan. 4MAXI team, Institute of Physical and Chemical Research (RIKEN), 2-1 Hirosawa, Wako, Saitama 351-0198, Japan. 5Department of Astronomy and Astrophysics, The Pennsylvania State University, 525 Davey Laboratory, University Park, Pennsylvania 16802, USA. 6Department of Physics and Astronomy, University of Leicester, University Road, Leicester LE1 7RH, UK. 7International Centre for Radio Astronomy Research / Curtin University, GPO Box U1987, Perth, WA 6845, Australia. 8Department of Physics and Astronomy, Stony Brook University, Stony Brook, NY 11794-3800, USA. 9Mullard Space Science Laboratory, University College London, Holmbury St Mary, Dorking, Surrey RH5 6NT, UK. 10Department of Astronomy, Kyoto University, Oiwake-cho, Sakyo-ku, Kyoto 606-8502, Japan. 11NASA Goddard Space Flight Center, Greenbelt, Maryland 20771, USA. 12School of Dentistry at Matsudo, Nihon University, 2-870-1 Sakaecho-nishi, Matsudo, Chiba 271-8587, Japan. 13Southwest Research Institute, Space Science and Engineering Division, PO Drawer 28510, San Antonio, Texas 78228-0510, USA. 14Department of Physics, Faculty of Science and Engineering, Chuo University, 1-13-27 Kasuga, Bunkyo-ku, Tokyo 112-8551, Japan. 15Department of Earth and Space Science, Osaka University, 1-1 Machikaneyama, Toyonaka, Osaka 560-0043, Japan. 16Department of Physics and Mathematics, Aoyama Gakuin University, 5-10-1 Fuchinobe, Chuo-ku, Sagamihara, Kanagawa 252-5258, Japan.

Ground calibration of X-ray CCD camera XIS onboard ASTRO-E

Abstract We report on the X-ray response of the X-ray CCD camera X-ray Imaging Spectrometer (XIS) onboard the X-ray Astronomical Satellite, ASTRO-E, which will be launched in February of 2000. The XIS is prepared by an international team, comprising MIT (USA), ISAS, Osaka Univ. and Kyoto Univ. (JAPAN). We evaluate the X-ray response of engineering model (EM) of the XIS at the high energy band of 1.5–10 keV. Fluorescent lines from Al, Cl, Ti, Ni, Fe, Zn are irradiated on the CCD chips, and are used to construct the response function. Details of the response function; energy-scale, linearity, energy resolution, quantum efficiency and etc, are given as a function of incident X-ray energies.

Non thermal X-ray from galactic supernova remnants

Abstract 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.