论文标题
$ \ it {xxl} $调查：XL。 $ \ it {xxl-n} $中红色agn的模糊属性
The $\it{XXL}$ survey: XL. Obscuration properties of red AGN in $\it{XXL-N}$
论文作者
论文摘要
光学和中红外（miR）光度法的组合已广泛用于选择红色活跃的银河核（AGN）。我们的目的是通过X射线光谱和光谱能量分布（SED）探索这些红色AGN的模糊性能。在这项研究中，我们重新介绍光学/miR灭绝与X射线吸收之间的关系。我们使用IR选择标准，特别是$ W1 $和$ W2 $ WISE频段，以识别$ \ it {XMM-XXL} $ afore中的4798 AGNS（$ \ sim 25 $ deg $^2 $）。光学/mir颜色的应用（$ r- w2> 6 $）揭示了561个红色AGN（14 $ \％$）。其中47个可用的X射线光谱，每个检测器至少有50个净（背景提取）计数。对于这些来源，我们使用CIGALE代码构建了从光学到MIR的SED。 SED拟合表明，后47个来源中有44个基于AGN发射和估计的倾斜角表现出明显的遮挡迹象。安装SED还揭示了由Galaxy主导的十个系统（$ \ sim20 \％$）。在这些情况下，红色归因于宿主星系而不是AGN吸收。在我们的样品中不包括这十个系统和应用X射线光谱拟合分析表明，红外Red AGNS的最高$ 76 \％$（28/37）具有X射线吸收的迹象。因此，虽然有9个来源（样品的$ \ sim20 \％$），尽管光红色，但并未被吸收。这些来源中约有$ 50 \％$在其光谱中呈现宽阔的排放线。我们建议这种明显差异的原因是R-W2标准相对于X射线光谱法对较小量的遮掩性敏感。总之，似乎大多数红色AGN具有相当大的遮挡水平，如其SED所示。它们的X射线吸收是中等的，平均值为$ \ rm n_h \ sim 10^{22} \，\ rm {cm^{ - 2}} $。
The combination of optical and mid-infrared (MIR) photometry has been extensively used to select red active galactic nuclei (AGNs). Our aim is to explore the obscuration properties of these red AGNs with both X-ray spectroscopy and spectral energy distributions (SEDs). In this study, we re-visit the relation between optical/MIR extinction and X-ray absorption. We use IR selection criteria, specifically the $W1$ and $W2$ WISE bands, to identify 4798 AGNs in the $\it{XMM-XXL}$ area ($\sim 25$deg$^2$). Application of optical/MIR colours ($r- W2 > 6$) reveals 561 red AGNs (14$\%$). Of these, 47 have available X-ray spectra with at least 50 net (background-subtracted) counts per detector. For these sources, we construct SEDs from the optical to the MIR using the CIGALE code. The SED fitting shows that 44 of these latter 47 sources present clear signs of obscuration based on the AGN emission and the estimated inclination angle. Fitting the SED also reveals ten systems ($\sim20\%$) which are dominated by the galaxy. In these cases, the red colours are attributed to the host galaxy rather than AGN absorption. Excluding these ten systems from our sample and applying X-ray spectral fitting analysis shows that up to $76\%$ (28/37) of the IR red AGNs present signs of X-ray absorption. Thus, there are nine sources ($\sim20\%$ of the sample) that although optically red, are not substantially X-ray absorbed. Approximately $50\%$ of these sources present broad emission lines in their optical spectra. We suggest that the reason for this apparent discrepancy is that the r-W2 criterion is sensitive to smaller amounts of obscuration relative to the X-ray spectroscopy. In conclusion, it appears that the majority of red AGNs present considerable obscuration levels as shown by their SEDs. Their X-ray absorption is moderate with a mean of $\rm N_H \sim 10^{22}\, \rm{cm^{-2}}$.
