NuSTAR SPECTROSCOPY OF GRS 1915+105: DISK REFLECTION, SPIN, AND CONNECTIONS TO JETS
NuSTAR SPECTROSCOPY OF GRS 1915+105: DISK REFLECTION, SPIN, AND CONNECTIONS TO JETS
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DOI：
10.1088/2041-8205/775/2/l45
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发表时间：
2013-08
期刊：
影响因子：
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通讯作者：
J. Miller;M. Parker;F. Fuerst;M. Bachetti;F. Harrison;D. Barret;S. Boggs;D. Chakrabarty;F. Chris
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文献类型：
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作者：
J. Miller;M. Parker;F. Fuerst;M. Bachetti;F. Harrison;D. Barret;S. Boggs;D. Chakrabarty;F. Chris
我们报告的光谱拟合的结果作出的努斯塔观察黑洞GRS 1915+105在“高原”状态。这种状态特别令人感兴趣，因为它类似于其他黑洞中的“低/硬”状态，特别是在这个阶段发射的紧凑，稳定的喷流。努斯塔的3-79千电子伏带通，以及它获得中等分辨率光谱的能力，没有扭曲，如光子堆积，非常适合于研究磁盘反射的X射线双星。在仅15 ks的净曝光量下，在整个带通范围内测量到GRS 1915+105的非常灵敏的光谱。很明显，需要从一个快速旋转的黑洞周围的圆盘电离反射来拟合光谱;即使是混合康普顿化模型，包括从一个史瓦西黑洞周围的圆盘电离反射，也被证明是不够的。通过最佳拟合模型测量的自旋参数为a = 0.98 ± 0.01（1σ统计误差）;在高置信水平下排除了低自旋。这一结果表明，喷射流可以从延伸到最内侧稳定圆形轨道的圆盘发射。一个非常陡峭的内部磁盘的发射率分布也测量，符合模型的紧凑型日冕以上克尔黑洞。这些结果支持一个新兴的硬X射线日冕和相对论性喷流的基础之间的关联。
We report on the results of spectral fits made to a NuSTAR observation of the black hole GRS 1915+105 in a “plateau” state. This state is of special interest because it is similar to the “low/hard” state seen in other black holes, especially in that compact, steady jets are launched in this phase. The 3–79 keV bandpass of NuSTAR, and its ability to obtain moderate-resolution spectra free from distortions such as photon pile-up, are extremely well suited to studies of disk reflection in X-ray binaries. In only 15 ks of net exposure, an extraordinarily sensitive spectrum of GRS 1915+105 was measured across the full bandpass. Ionized reflection from a disk around a rapidly spinning black hole is clearly required to fit the spectra; even hybrid Comptonization models including ionized reflection from a disk around a Schwarzschild black hole proved inadequate. A spin parameter of a = 0.98 ± 0.01 (1σ statistical error) is measured via the best-fit model; low spins are ruled out at a high level of confidence. This result suggests that jets can be launched from a disk extending to the innermost stable circular orbit. A very steep inner disk emissivity profile is also measured, consistent with models of compact coronae above Kerr black holes. These results support an emerging association between the hard X-ray corona and the base of the relativistic jet.