论文标题
典型的X射线荧光线强度作为色谱柱密度指标
Canonical X-Ray Fluorescence Line Intensities as Column Density Indicators
论文作者
论文摘要
X射线线荧光在强大的积聚来源，即活跃的银河核和X射线二进制物周围无处不在。最明亮，最良好的线路是$λ= 1.937 $Å（6.4 \，KEV）的Fe K $α$线。本文介绍了所有测量的Chandra/Hetg光栅光谱，该光谱具有来自MG和NI之间元素的几个K $α$荧光线。尽管来源和身体状况各不相同，但我们确定了一个共同的趋势，该趋势决定了元素之间的K $α$线强度比。在大多数情况下，线强度通过简单的，平行的平行近似值的近乎中性，太阳能，高柱密度（$ n _ {\ textrm {h}}> 10^{24} $ cm $^{ - 2} $）中型。该近似值给出了所有元素的K $α$荧光的规范光子强度线比，例如0.104：\，0.069：\，1.0：\，0.043，分别为Si：\，S：\，S：\，Fe，Fe：\，Fe：\，Ni。证明与这些比率的偏差主要是由于沿着银河柱以外的视线过多的柱密度造成的。因此，测得的荧光线比提供了$ n _ {\ textrm {h}} $的独立估计，并深入了解积聚源环境。与规范比率的残留差异可能是由于各种效果，例如具有$ n _ {\ textrm {h}} <10^{24} $ \，cm $^{ - 2} $的荧光培养基，一种非层次的介质，或irrectir a in ir irreg acle nirren ceentry，cm $^{ - 2} $，一种非媒介。但是，显然，也许令人惊讶的是，这些并不常见，它们的影响仍然很小。
X-ray line fluorescence is ubiquitous around powerful accretion sources, namely active galactic nuclei and X-ray binaries. The brightest and best-studied line is the Fe K$α$ line at $λ= 1.937$Å(6.4\,keV). This paper presents a survey of all well-measured Chandra/HETG grating spectra featuring several K$α$ fluorescence lines from elements between Mg and Ni. Despite the variety of sources and physical conditions, we identify a common trend that dictates the K$α$ line intensity ratios between elements. For the most part, the line intensities are well described by a simple, plane-parallel approximation of a near-neutral, solar-abundance, high column density ($N_{\textrm{H}} > 10^{24}$ cm$^{-2}$) medium. This approximation gives canonical photon-intensity line ratios for the K$α$ fluorescence of all elements, e.g., 0.104:\,0.069:\,1.0:\,0.043 for Si:\,S:\,Fe:\,Ni, respectively. Deviations from these ratios are shown to be primarily due to excess column density along the line of sight beyond the Galactic column. Therefore, measured fluorescence line ratios provide an independent estimate of $N_{\textrm{H}}$ and insight into the environment of accretion sources. Residual discrepancies with the canonical ratios could be due to a variety of effects such as a fluorescing medium with $N_{\textrm{H}} < 10^{24}$\,cm$^{-2}$, a non-neutral medium, variations in the illuminating spectrum, non-solar abundances, or an irregular source geometry. However, evidently and perhaps surprisingly, these are uncommon, and their effect remains minor.
