The X-Ray Spectra of Black Hole X-Ray Novae in Quiescence as Measured by Chandra
The X-Ray Spectra of Black Hole X-Ray Novae in Quiescence as Measured by Chandra
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DOI：
10.1086/339501
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发表时间：
2001-11
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影响因子：
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通讯作者：
A. Kong;J. McClintock;Michael R. Garcia;S. Murray;D. Barret
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文献类型：
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作者：
A. Kong;J. McClintock;Michael R. Garcia;S. Murray;D. Barret
本文介绍了Chandra对V404 Cyg、A0620-00、GRO J1655-40和XTE J1550-564黑洞X射线新星在静止期的观测结果。它们的静态光谱可用指数斜率为α ~ 2的幂律模型拟合。虽然日冕（Raymond-Smith）模型也是统计上可接受的光谱表示，但这些模型的最佳拟合温度比活跃恒星日冕中的温度高约5倍。这四个光谱的静态X射线新星都是一致的，预期通过对流为主的吸积流吸积和不一致的预期从恒星日冕。这一静止状态下持续吸积的证据进一步加强了黑洞视界存在的理由。A0620-00和GRO J1655-40都比以前的观测要暗，而天鹅座V404则更明亮，在几千秒内变化了2倍。对XTE J1550-564的X射线数据的重新分析表明，它的光度（像V404 Cyg和A0620-00一样）超过了日冕模型的最大预测值。所研究的四个源的0.3-7 keV亮度范围为~1030至1033尔格s-1。
We present Chandra observations of black hole X-ray novae V404 Cyg, A0620-00, GRO J1655-40, and XTE J1550-564 in quiescence. Their quiescent spectra can be well fitted by a power-law model with number slope α ~ 2. While a coronal (Raymond-Smith) model is also a statistically acceptable representation of the spectra, the best-fit temperatures of these models is ~5 times higher than that seen in active stellar coronae. These four spectra of quiescent X-ray novae are all consistent with that expected for accretion via an advection-dominated accretion flow and inconsistent with that expected from a stellar corona. This evidence for continued accretion in quiescence further strengthens the case for the existence of event horizons in black holes. Both A0620-00 and GRO J1655-40 were fainter than in previous observations, while V404 Cyg was more luminous and varied by a factor of 2 in a few kiloseconds. A reanalysis of the X-ray data for XTE J1550-564 shows that (like V404 Cyg and A0620-00) its luminosity exceeds the maximum prediction of the coronal model by a large factor. The 0.3-7 keV luminosities of the four sources studied are in the range from ~1030 to 1033 ergs s-1.