The iron Kα line complex in Compton-thick Seyfert 2 galaxies
The iron Kα line complex in Compton-thick Seyfert 2 galaxies
复制标题
康普顿厚的 Seyfert 2 星系中的铁 Kα 线复合体
DOI：
10.1093/mnras/280.3.823
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发表时间：
1996
影响因子：
4.8
通讯作者：
A. Fabian
中科院分区：
文献类型：
--
作者：
G. Matt;W. Brandt;A. Fabian
我们计算了活动星系核（AGN）中的荧光和共振散射铁Kex线的强度，在这些活动星系核中，线能量处的初级辐射完全被视线上的干扰物质沿着阻挡（所谓的“康普顿厚度”的Seyfert 2星系）。在塞弗特星系的统一模型的框架中，无论是“冷”荧光线从模糊的环面和高度电离线从温暖的材料负责的散射和偏振的光学光子的预期。如果物质的厚度是康普顿厚度，那么来自模糊圆环的中性铁谱线相对于由相同物质反射的连续谱具有1-2 keY量级的等效宽度。从温暖的材料，在光学薄制度的所有相关的过程中，线发射是占主导地位的共振散射线。然而，对于这种物质的合理物理条件，谐振线在其中心可能是光学厚的。在这种情况下，谐振线强度可以显著降低，并且对于LT ~ 0.1，荧光/复合线主导谐振线。我们提出了在光学薄的情况下，和数值结果（通过Monte Carlo模拟得到）的光学厚的情况下的等效宽度的铁线的解析公式。我们将理论结果应用到最著名的康普顿厚源，塞弗特2星系NGC 1068。在连续谱的形状和线的等效宽度的大的不确定性，防止任何明确的结论，但应用程序可以被看作是一个例子，如何在本文中提出的结果可以用来估计物理和几何量在模糊活动星系核。
We calculate the intensities of the fluorescent and resonantly scattered iron Kex lines in those active galactic nuclei (AGN) in which the primary radiation at the line energy is completely blocked by intervening matter along the line of sight (the so called 'Compton-thick' Seyfert 2 galaxies). In the framework of unification models for Seyfert galaxies, both a 'cold' fluorescent line from the obscuring torus and highly ionized lines from the warm material responsible for the scattering and polarization of optical photons are expected. The neutral iron line from the obscuring torus has an equivalent width, with respect to the continuum reflected by the same matter, of order 1-2 keY, provided that the matter is Compton thick. The line emission from the warm material, in the optically thin regime for all relevant processes, is dominated by the resonantly scattered lines. However, for plausible physical conditions of this matter, the resonant lines are likely to be optically thick in their centres. In this case, the resonant line intensity can significantly decrease, and for LT ~ 0.1 the fluorescent/recombination lines dominate the resonant lines. We present analytical formulae for the equivalent widths of iron lines in the optically thin case, and numerical results (obtained by means of Monte Carlo simulations) for the optically thick case. We apply the theoretical results to the most famous Compton-thick source, the Seyfert 2 galaxy NGC 1068. The large uncertainties in the continuum spectral shape and line equivalent widths prevent any definite conclusions, but the application can be regarded as an example of how the results presented in this paper could be used to estimate physical and geometrical quantities in obscured AGN.