On the determination of the spin and disc truncation of accreting black holes using X-ray reflection
On the determination of the spin and disc truncation of accreting black holes using X-ray reflection
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DOI：
10.1093/mnras/stu045
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发表时间：
2014-01
影响因子：
4.8
通讯作者：
A. Fabian;M. Parker;D. Wilkins;J. Miller;E. Kara;C. Reynolds;T. Dauser
中科院分区：
文献类型：
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作者：
A. Fabian;M. Parker;D. Wilkins;J. Miller;E. Kara;C. Reynolds;T. Dauser
本文讨论了简单的相对论模糊X射线反射模型在吸积黑洞盘的自旋和内半径确定中的应用。观测上，日冕的性质是不确定的先验，但一个强大的确定的内部磁盘半径时，磁盘的发射率指数是严格限制。当内部圆盘被很好地照亮时，黑洞的自旋也可以被确定。使用来自射线追踪的反射建模，我们表明，强大的确定盘截断需要的位置的冠状源是准静态的，并在高度和半径小于盘的截断半径。稳健的自旋测量要求日冕的至少一部分位于黑洞上方小于10个引力半径的地方，以便最里面的区域，包括最里面的稳定圆形轨道，得到很好的照明。模糊核的宽度（例如，铁线）对日冕高度有很强的依赖性。这些限制可能特别适用于低爱丁顿分数（例如低/硬状态和低光度AGN），其中日冕的高度可能相对较大，或流出，并与喷流产生有关。
We discuss the application of simple relativistically-blurred X-ray reflection models to the determination of the spin and the inner radius of the disc in accreting black holes. Observationally, the nature of the corona is uncertain a priori, but a robust determination of the inner disk radius can be made when the disc emissivity index is tightly constrained. When the inner disc is well illuminated, the black hole spin can also be determined. Using reflection modelling derived from ray tracing, we show that robust determination of disc truncation requires that the location of the coronal source is quasi-static and at a height and radius less than the truncation radius of the disc. Robust spin measurements require that at least part of the corona lies less than about 10 gravitational radii above the black hole in order that the innermost regions, including the innermost stable circular orbit, are well illuminated. The width of the blurring kernel (e.g., the iron line) has a strong dependence on coronal height. These limitations may be particularly applicable at low Eddington fractions (e.g. the low/hard state, and low-luminosity AGN) where the height of the corona may be relatively large, or outflowing, and tied to jet production.