论文标题
活性银河核中X射线和光吸收器之间的关系
The relationship between X-ray and optical absorbers in active galactic nuclei
论文作者
论文摘要
我们提出了通过测得的X射线柱密度的活性银河核（AGN）的宽线Balmer减少的红色估计值的大量汇编。 1型1.9至1.9 Agns的中间红色为E（B-V）〜0.77 +/- 0.10，具有报告的柱密度。这明显高于SDSS中AGN的中位数。我们将其归因于SDSS的选择偏差，归功于蓝色AGN。对于其他AGN，我们发现出版偏见反对报告低柱密度的证据。我们发现N_H和E（B-V）之间存在显着相关性，但大量+/- 1个DEX（不考虑测量中的不确定性）。平均而言，X射线柱与太阳邻域尘埃与气体比的E（B-V）预测的列是一致的。我们认为，可以通过X射线柱密度的变异性来解释柱密度和红色的大量散布。对于具有可检测到的宽线区域（BLR）的AGN，与标准1.9 AGN相比，我们没有发现N_H或E（B-V）在N_H或E（B-V）上有任何统计学上的显着差异。没有证据表明任何1型AGN被厚厚。我们还分析了2型AGN，发现N_H与窄线区域之间没有显着相关性。衬套的中值柱密度为22.68 +/- 0.75，而类型2的柱密度为22.90 +/- 0.28。我们发现大多数低柱密度2型是衬里，但是由于散射的X射线光稀释光电边缘，N_H可能被低估了。
We present a large compilation of reddening estimates from broad-line Balmer decrements for active galactic nuclei (AGNs) with measured X-ray column densities. The median reddening is E(B-V) ~ 0.77 +/- 0.10 for type-1 to type-1.9 AGNs with reported column densities. This is notably higher than the median reddening of AGNs from the SDSS. We attribute this to the selection bias of the SDSS towards blue AGNs. For other AGNs we find evidence of a publication bias against reporting low column densities. We find a significant correlation between N_H and E(B-V) but with a large scatter of +/- 1 dex (without accounting for uncertainties in measurements). On average the X-ray columns are consistent with those predicted from E(B-V) for a solar neighbourhood dust-to-gas ratio. We argue that the large scatter of column densities and reddenings can be explained by X-ray column-density variability. For AGNs with detectable broad-line regions (BLRs) that have undergone significant changes of Seyfert type (changing-look AGNs) we do not find any statistically significant differences in N_H or E(B-V) compared to standard type-1 to type-1.9 AGNs. There is no evidence for any type-1 AGNs being Compton-thick. We also analyze type-2 AGNs and find no significant correlation between N_H and narrow-line region reddening. The median column density of LINERs is 22.68 +/- 0.75 compared to a column density of 22.90 +/- 0.28 for type-2s. We find the majority of low column density type-2s are LINERs, but N_H is probably underestimated because of scattered X-ray light diluting the photoelectric edge.
