IS THE BLACK HOLE IN GX 339−4 REALLY SPINNING RAPIDLY?
IS THE BLACK HOLE IN GX 339−4 REALLY SPINNING RAPIDLY?
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GX 339−4 中的黑洞真的快速旋转吗？
DOI：
10.1088/0004-637x/707/2/l109
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发表时间：
2009
期刊：
影响因子：
--
通讯作者：
P. Gandhi
中科院分区：
文献类型：
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作者：
S. Yamada;K. Makishima;Y. Uehara;K. Nakazawa;H. Takahashi;T. Dotani;Y. Ueda;K. Ebisawa;A. Kubota;P. Gandhi
重新分析了2007年2月在甚高态时获得的黑洞双星GX339−4的宽带Suzaku谱。仔细考虑了X射线成像光谱仪(XIS)数据的事件堆积(在图像中心的∼3‘内显著)和遥测饱和的影响。探测到∼300keV的源，在8kpc时，未吸收的0.5keV-200keV的光度为3.8×1038erg S−1。光谱可以用光子指数2.7的幂定律来近似，具有温和的软过剩和硬X射线驼峰。当使用图像中心2‘之外的XIS数据时，Fe K线看起来非常宽，这表明BH自旋很高，正如Miller等人已经报道的那样。基于相同的Suzaku数据和其他CCD数据。当XIS数据累积被进一步限制到<gt；3‘以避免事件堆积时，Fe K分布变得更窄，并且出现了略微更好的解决方案，该解决方案建议内盘半径是引力半径(1σ)的5-14倍，尽管在90%的置信度水平下数据仍然允许最大自转的BH。一贯地，光学厚度的吸积盘被推断为以引力半径的5-32倍的半径被截断。因此，Suzaku的数据允许另一种解释，而不需要引用快速旋转的BH。这一推断还得到了先前在高/软状态下测量的盘半径的支持。
The wide-band Suzaku spectra of the black hole (BH) binary GX 339−4, acquired in 2007 February during the Very High state, were reanalyzed. Effects of event pileup (significant within ∼3′ of the image center) and telemetry saturation of the X-ray Imaging Spectrometer (XIS) data were carefully considered. The source was detected up to ∼300 keV, with an unabsorbed 0.5–200 keV luminosity of 3.8 × 1038 erg s−1 at 8 kpc. The spectrum can be approximated by a power law of photon index 2.7, with a mild soft excess and a hard X-ray hump. When using the XIS data outside 2′ of the image center, the Fe K line appeared extremely broad, suggesting a high BH spin as already reported by Miller et al. based on the same Suzaku data and other CCD data. When the XIS data accumulation is further limited to >3′ to avoid event pileup, the Fe K profile becomes narrower, and a marginally better solution appears which suggests that the inner disk radius is 5–14 times the gravitational radius (1σ), though a maximally spinning BH is still allowed by the data at the 90% confidence level. Consistently, the optically thick accretion disk is inferred to be truncated at a radius 5–32 times the gravitational radius. Thus, the Suzaku data allow an alternative explanation without invoking a rapidly spinning BH. This inference is further supported by the disk radius measured previously in the High/Soft state.
影响因子：
2.3
作者：
M. Kokubun;K. Makishima;T. Takahashi;T. Murakami;M. Tashiro;Y. Fukazawa;T. Kamae;G. Madejski
通讯作者：
M. Kokubun;K. Makishima;T. Takahashi;T. Murakami;M. Tashiro;Y. Fukazawa;T. Kamae;G. Madejski
用朱雀观测到的 GRO J1655 -40 的低/硬态光谱
DOI：
--
发表时间：
2008
期刊：
Low/Hard State Spectra of GRO J1655 - 40 Observed with Suzaku 60
影响因子：
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作者：
Takahashi;H.;Y. Fukazawa;T. Mizuno;A. Hirasawa;S. Kitamoto;K. Sudoh;T. Ogita;A. Kubota;K. Makishima;T. Itoh;A. N. Parmar;K. Ebisawa;S. Naik;T. Dotani;M. Kokubun;K. Ohnuki;T. Takahashi;T. Yaqoob;L. Angelini;Y. Ueda;K. Yamaoka;T. Kotan
通讯作者：
T. Kotan