Abstract

We have developed a Monte Carlo code for simulation of X-ray spectra of active galactic nuclei (AGN) based on a model of a clumpy obscuring torus. Using this code, we investigate the diagnostic power of X-ray spectroscopy of obscured AGN with respect to the physical properties and orientation of the torus, namely: the average column density, \(\langle N_{\textrm{H}}\rangle\), the line-of-sight column density, \(N_{\textrm{H}}\), the abundance of iron, \(A_{\textrm{Fe}}\), the clumpiness (i.e., the average number of gas clouds along the line of sight), \(\langle N\rangle\), and the viewing angle, \(\alpha\). In this first paper of a series, we consider the Compton-thin case, where both \(\langle N_{\textrm{H}}\rangle\) and \(N_{\textrm{H}}\) do not exceed \(10^{24}\) cm\({}^{-2}\). To enable quantitative comparison of the simulated spectra, we introduce five measurable spectral characteristics: the low-energy hardness ratio (ratio of the continuum fluxes in the 7–11 and 2–7 keV energy bands), the high-energy hardness ratio (ratio of the continuum fluxes in the 10–100 and 2–10 keV energy bands), the depth of the iron K absorption edge, the equivalent width of the Fe K\(\alpha\) line, and the fraction of the Fe K\(\alpha\) flux contained in the Compton shoulder. We demonstrate that by means of X-ray spectroscopy it is possible to tightly constrain \(\langle N_{\textrm{H}}\rangle\), \(N_{\textrm{H}}\), and \(A_{\textrm{Fe}}\) in the Compton-thin regime, while there is degeneracy between clumpiness and viewing direction.

中文翻译：

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我们可以从康普顿薄 AGN Tori 的 X 射线光谱中了解到什么？*

摘要

我们开发了一种蒙特卡罗代码，用于基于块状模糊环面模型模拟活动星系核 (AGN) 的 X 射线光谱。使用此代码，我们研究了模糊 AGN 的 X 射线光谱对环面物理特性和方向的诊断能力，即：平均柱密度， \(\langle N_{\textrm{H}}\ rangle \)、视线柱密度、\(N_{\textrm{H}}\)、铁丰度、\(A_{\textrm{Fe}}\)、团块度（即平均沿视线的气体云数量）、\(\langle N\rangle\)和视角\(\alpha\)。在该系列的第一篇论文中，我们考虑康普顿薄情况，其中\(\langle N_{\textrm{H}}\rangle\)和\(N_{\textrm{H}}\)都不超过\(10^{24}\) 厘米\({}^{-2}\)。为了能够对模拟光谱进行定量比较，我们引入了五个可测量的光谱特征：低能硬度比（7-11 和 2-7 keV 能带中连续通量的比率）、高能硬度比（7-11 和 2-7 keV 能带中连续通量的比率）、高能硬度比（ 10-100 和 2-10 keV 能带中的连续通量）、铁 K 吸收边的深度、Fe K \(\alpha\)线的等效宽度以及 Fe K \的分数康普顿肩中包含的(\alpha\)通量。我们证明，通过 X 射线光谱法，可以严格约束\(\langle N_{\textrm{H}}\rangle\)、\(N_{\textrm{H}}\)和\(A_ {\textrm{Fe}}\)处于康普顿薄态，而团块和观察方向之间存在简并。