arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 1102.4247astro-ph.HE
收藏

X射线偏振测量中吸积黑洞的光弯曲方案

Light bending scenario for accreting black holes in X-ray polarimetry

M. Dovciak, F. Muleri, R. W. Goosmann, V. Karas, G. Matt

摘要:

讨论了旋转黑洞的吸积盘上方的X射线照射源模型。在所谓的灯柱计划中,我们计算到达观察者的辐射的预期(观察到的)偏振特性。我们探讨模型参数的依赖关系,采用蒙特卡罗辐射传输计算的X射线的吸积盘上的反射,并考虑广义相对论的影响。特别是,我们讨论了黑洞自旋的作用,观察者的视角,和主要的X射线源距离的黑洞。我们给出了两种类型的典型对象-活动星系核和银河系黑洞的偏振度的几个例子。为了评估潜在的可观测性的偏振功能,我们假设的灵敏度建议新硬X射线任务(NHXM)。我们研究的能量范围从几keV到~50 keV,所以铁线复合物和康普顿峰包括在我们的模型光谱。我们发现所得的极化度在所研究的能带的高端,即在>~20 keV处增加。因此,最好的结果,偏振反射光谱应达到康普顿峰能量区。当黑洞自旋较大、主源高度较小、观测者倾角较小时,我们也得到了较高的极化度。

英文摘要:

We discuss a model of an X-ray illuminating source above an accretion disk of a rotating black hole. Within the so called lamp-post scheme we compute the expected (observed) polarization properties of the radiation reaching an observer. We explore the dependencies on model parameters, employing Monte Carlo radiation transfer computations of the X-ray reflection on the accretion disk and taking general relativity effects into account. In particular, we discuss the role of the black hole spin, of the observer viewing angle, and of the primary X-ray source distance from the black hole. We give several examples of the resulting polarization degree for two types of exemplary objects - active galactic nuclei and Galactic black holes. In order to assess potential observability of the polarization features, we assume the sensitivity of the proposed New Hard X-ray Mission (NHXM). We examine the energy range from several keV to ~50 keV, so the iron-line complex and the Compton hump are included in our model spectra. We find the resultant polarization degree to increase at the higher end of the studied energy band, i.e. at >~20 keV. Thus, the best results for polarimetry of reflection spectra should be achieved at the Compton hump energy region. We also obtain higher polarization degree for large spin values of the black hole, small heights of the primary source, and low inclination angles of the observer.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

↑