论文标题
Chandra Deep-South调查中的多波长选定的Compton-Thick-Thick Agns
Multi-wavelength Selected Compton-thick AGNs in Chandra Deep Field-South Survey
论文作者
论文摘要
即使在深X射线调查中，Compton-Thick-Active Galactic Nuclei（Ct Agns，$ {\ rm n_h} \ geqslant 1.5〜 \ times〜10^{24}〜{\ rm cm}^{ - 2} $由于X射线的速度及其复杂的范围而难以识别。但是，CT AGN的研究对于理解黑洞的快速生长和宇宙X射线背景的起源至关重要。在当地宇宙中，CT AGN的比例占整个AGN人群的30％。我们可能会预计，在深X射线调查中，CT AGN的比例较高，但是，在7 ms \ textit {chandra}中，只有10％的AGN被鉴定为CT AGNS。在这项工作中，我们选择了51个具有丰富多波长数据的AGN。使用中红外（MID-IR）过量的方法，我们在样本中选择了迄今未知的8个CT AGN候选。这些候选者中有七个可以基于多波长识别方法确认为CT AGN，并通过MID-IR诊断识别新的CT AGN（XID 133）。我们还讨论了这八个CT AGN的X射线起源，以及在先前的研究中低估其色谱柱密度的原因。我们发现，如果观察数据的高质量，选择CT AGN的多波长方法是高效的。我们还发现，CT AGN的Eddington比率高于非CT AGN，并且CT AGN和非CT AGNS均显示出宿主星系的相似特性。
Even in deep X-ray surveys, Compton-thick active galactic nuclei (CT AGNs, ${\rm N_H} \geqslant 1.5~\times~10^{24}~{\rm cm}^{-2}$) are difficult to be identified due to X-ray flux suppression and their complex spectral shape. However, the study of CT AGNs is vital for understanding the rapid growth of black holes and the origin of cosmic X-ray background. In the local universe, the fraction of CT AGNs accounts for 30% of the whole AGN population. We may expect a higher fraction of CT AGNs in deep X-ray surveys, however, only 10% of AGNs have been identified as CT AGNs in the 7 Ms \textit{Chandra} Deep Field-South (CDFS) survey. In this work, we select 51 AGNs with abundant multi-wavelength data. Using the method of the mid-infrared (mid-IR) excess, we select hitherto unknown 8 CT AGN candidates in our sample. Seven of these candidates can confirm as CT AGN based on the multi-wavelength identification approach, and a new CT AGN (XID 133) is identified through the mid-IR diagnostics. We also discuss the X-ray origin of these eight CT AGNs and the reason why their column densities were underestimated in previous studies. We find that the multi-wavelength approaches of selecting CT AGNs are highly efficient, provided the high quality of observational data. We also find that CT AGNs have a higher Eddington ratio than non-CT AGNs, and that both CT AGNs and non-CT AGNs show similar properties of host galaxies.
