Low/hard state spectra of GRO J1655-40 observed with Suzaku

被引：0
作者：
Department of Physical Science, School of Science, Hiroshima University, 1-3-1 Kagamiyama, Higashi-Hiroshima, Hiroshima 739-8526, Japan [1 ]
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机构：
[1] Department of Physical Science, School of Science, Hiroshima University, Higashi-Hiroshima, Hiroshima 739-8526
[2] Department of Physics, Rikkyo University, Toshima-ku, Tokyo 171-8501
[3] Department of Electronic Information Systems, Shibaura Institute of Technology, Minuma-ku, Saitama 337-8570
[4] Cosmic Radiation Laboratory, Institute of Physical and Chemical Research (RIKEN), Wako-shi, Saitama 351-0198
[5] Department of Physics, University of Tokyo, Bunkyo-ku, Tokyo 113-0033
[6] Astrophysics Mission Division, Research and Scientific Support Department of ESA, ESTEC, NL-2200 AG Noordwijk
[7] Institute of Space and Astronautical Science, JAXA, Sagamihara, Kanagawa 229-8510
[8] Department of Physics and Astronomy, Johns Hopkins University, Baltimore, MD 21218, 3400 N, Charles St.
[9] Explosion of the Universe Division, NASA Goddard Space Flight Center, Greenbelt
[10] Department of Astronomy, Kyoto University, Sakyo-ku, Kyoto 606-8502, Kitashirakawa-Oiwake-cho
[11] Department of Physics and Mathematics, Aoyama Gakuin University, Sagamihara, Kanagawa 229-8558
[12] Department of Physics, Tokyo Institute of Technology, Meguro-ku, Tokyo 152-8551
[13] Department of Earth and Space Science, Graduate School of Science, Osaka University, Toyonaka, Osaka 560-0043
[14] Physics Department, Kogakuin University, Hachioji, Tokyo 192-0015
[15] Department of Physics, College of Science and Technology, Nihon University, Chiyoda-ku, Tokyo 101-8308
来源：
Publications of the Astronomical Society of Japan | 2008年 / 60卷 / SPEC. ISS. 1期
关键词：
Accretion disks; Black hole physics; Stars: individual (GRO J1655-40); X-ray: Binaries;
D O I：
10.1093/pasj/60.sp1.s69
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学科分类号：
摘要：
The Galactic black-hole binary GRO J1655-40, a source harboring superluminal jets, was observed with Suzaku on 2005 September 22-23. The source was detected over a broad and continuous energy range of 0.7-300 keV, with an intensity of ∼ 50 mCrab at 20keV. At a distance of 3.2kpc, the 0.7-300keV luminosity was ∼ 5.2 × 1036 erg s-1 (∼ 0.7% of the Eddington luminosity for a 6 M⊙ black hole). The source was in a typical low/hard state, exhibiting a power-law shaped continuum with a photon index of ∼ 1.6. During the observation, the source intensity gradually decreased by 25% at energies above ∼ 3 keV, and by 35% below 2keV. This, together with the soft X-ray spectra taken with the X-ray Imaging Spectrometer (XIS), suggests the presence of an independent soft component that can be represented by emission from a cool (∼0.2keV) disk. The hard X-ray spectra obtained with the Hard X-ray Detector reveal a high-energy spectral cutoff, with an e-folding energy of ∼ 200 keV. The entire 0.7-300 keV spectrum cannot be reproduced by a single thermal Comptonization model, even when considering reflection effects. Instead, the spectrum (except the soft excess) can be successfully explained by invoking two thermal-Comptonization components with different y-parameters. In contrast to the high/soft state spectra of this object, in which narrow iron absorption lines are detected with equivalent widths of 60-100 eV, the present XIS spectra bear no such features beyond an upper-limit equivalent width of 23 eV. © 2008. Astronomical Society of Japan.
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页码：S69 / S83
页数：14
相关论文
共 57 条
[1]  
Bailyn C.D., Et al., Nature, 374, (1995)
[2]  
Balucinska-Church M., Belloni T., Church M.J., Hasinger G., A&A, 302, (1995)
[3]  
Beloborodov A.M., ApJ, 510, (1999)
[4]  
Brocksopp C., Et al., MNRAS, 365, (2006)
[5]  
Diaz Trigo M., Parmar A.N., Boirin L., Mendez M., Kaastra J.S., A&A, 445, (2006)
[6]  
Diaz Trigo M., Parmar A.N., Miller J., Kuulkers E., Caballero-Garcia M.D., A&A, 462, (2007)
[7]  
Ebisawa K., Ueda Y., Inoue H., Tanaka Y., White N.E., ApJ, 467, (1996)
[8]  
Esin A.A., Narayan R., Cui W., Grove J.E., Zhang S.-N., ApJ, 505, (1998)
[9]  
Fabian A.C., Rees M.J., Stella L., White N.E., MNRAS, 238, (1989)
[10]  
Fender R.P., Belloni T.M., Gallo E., MNRAS, 355, (2004)
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