X-Ray Spectral Analyses of AGNs from the 7Ms Chandra Deep Field-South Survey: The Distribution, Variability, and Evolutions of AGN Obscuration
X-Ray Spectral Analyses of AGNs from the 7Ms Chandra Deep Field-South Survey: The Distribution, Variability, and Evolutions of AGN Obscuration
复制标题
7Ms 钱德拉深场南巡天活动星系核的 X 射线光谱分析：活动星系核遮蔽的分布、变化和演变
DOI：
10.3847/1538-4365/aa7847
复制
发表时间：
2017
影响因子：
8.7
通讯作者：
Mainieri
中科院分区：
文献类型：
--
作者：
Liu Teng;Tozzi Paolo;Wang Jun-Xian;Br;t William N.;Vignali Cristian;Xue Yongquan;Schneider Donald P.;Comastri Andrea;Yang Guang;Bauer Franz E.;Paolillo Maurizio;Luo Bin;Gilli Roberto;Wang Q. Daniel;Giavalisco Mauro;Ji Zhiyuan;Alex;er David M.;Mainieri
我们提出了一个详细的光谱分析的最亮的活动星系核（AGN）中确定的7 Ms钱德拉深场南（CDF-S）调查超过16年的时间跨度。利用本征吸收的幂律加反射模型，考虑到可能的软过剩和窄Fe Kα线，我们对7 Ms总照射量和4个不同时期（2-21个月）进行了系统的X射线谱分析。用这种方法，我们不仅提出了幂律斜率，柱密度，观测到的通量，和吸收校正的2-10 keV的光度LX为我们的样本的活动星系核，但也确定显着的光谱变化之间的时间尺度上的年。我们发现，可变性可以归因于两种不同类型的机制，无论是通量驱动或通量无关。我们还发现，窄Fe线EW和EW之间的相关性可以很好地解释为连续抑制随着增加。考虑到样本的不完整性和偏差，我们测量了CDF-S活动星系核的固有分布，并提出了重新选择的子样本，这些子样本在。完全子样本使我们能够解耦的依赖LX和红移。结合C-COSMOS的观测数据，我们证实了活动星系核的平均值与LX之间的关系，并发现在任何光度下，活动星系核的遮蔽率随红移的增加而显著增加。模糊分数可以描述为。
We present a detailed spectral analysis of the brightest active galactic nuclei (AGNs) identified in the 7Ms Chandra Deep Field-South (CDF-S) survey over a time span of 16 years. Using a model of an intrinsically absorbed power-law plus reflection, with possible soft excess and narrow Fe Kα line, we perform a systematic X-ray spectral analysis, both on the total 7Ms exposure and in four different periods with lengths of 2–21 months. With this approach, we not only present the power-law slopes, column densities , observed fluxes, and absorption-corrected 2–10 keV luminosities LX for our sample of AGNs, but also identify significant spectral variabilities among them on timescales of years. We find that the variabilities can be ascribed to two different types of mechanisms, either flux-driven or flux-independent. We also find that the correlation between the narrow Fe line EW and can be well explained by the continuum suppression with increasing . Accounting for the sample incompleteness and bias, we measure the intrinsic distribution of for the CDF-S AGN population and present reselected subsamples that are complete with respect to . The -complete subsamples enable us to decouple the dependences of on LX and on redshift. Combining our data with those from C-COSMOS, we confirm the anticorrelation between the average and LX of AGN, and find a significant increase of the AGN-obscured fraction with redshift at any luminosity. The obscured fraction can be described as .