论文标题
对低观察到的X射线与[OIII]光度比的Nustar观察结果：严重遮盖的AGN或关闭AGN？
NuSTAR Observations of AGN with Low Observed X-ray to [OIII] Luminosity Ratios: Heavily Obscured AGN or Turned-Off AGN?
论文作者
论文摘要
2型活性银河核（AGN）通过强，高电离的，狭窄的发射线在100s至1000 parsecs的尺度上延伸到超级质量黑洞上，但它们缺乏从近距离的宽发射线，从附近到黑孔，表征了1型1型AGN。缺乏广泛的发射可能表明最内向的核区域晦涩难懂，或者可能表明黑洞不再有强烈积聚。由于高能X射线可以穿透厚厚的遮盖柱，因此它们具有区分这两种情况的力量。我们提出了来自IRAS 12微米调查的9个Seyfert 2 AGN的高能量观察结果，并补充了Chandra，XMM-Newton和Swift的低能量X射线观测。与[O III]光亮性相比，星系被选择为2-10 keV光度，这是一种传统的被遮盖的AGN的传统诊断，达到了最高氢柱密度的康普顿厚度（$ n _ {$ n _ {\ rm H}> 1.5 \ rm h}> 1.5 \ \ rm h}> 1.5 \ \ times 10^24} cm}^{ - 2} $）。基于基于硬X射线光谱的物理建模的更新[O III]的光度和固有的X射线照明，我们发现一个星系被错误地分类为2型（NGC 5005），其余大多数AGN被遮盖了，其中三种被确认为Compton-Thick-Thick-Thick-Thick-Thick-Thick-Thick-Thick-Thick（IC 3639，NGC 1386，NGC 1386，和NGC 3982）。一个GARAXY，NGC 3627，似乎最近停用了。与原始样品相比，选择了9 AGN，这是大约1％的速率。我们还在NGC 6890中找到了新的X射线更换AGN。
Type 2 active galactic nuclei (AGN) show signatures of accretion onto a supermassive black hole through strong, high-ionization, narrow emission lines extended on scales of 100s to 1000s of parsecs, but they lack the broad emission lines from close in to the black hole that characterize type 1 AGN. The lack of broad emission could indicate obscuration of the innermost nuclear regions, or could indicate that the black hole is no longer strongly accreting. Since high-energy X-rays can penetrate thick obscuring columns, they have the power to distinguish these two scenarios. We present high-energy NuSTAR observations of 9 Seyfert 2 AGN from the IRAS 12 micron survey, supplemented with low-energy X-ray observations from Chandra, XMM-Newton, and Swift. The galaxies were selected to have anomalously low observed 2-10 keV luminosities compared to their [O III] optical luminosities, a traditional diagnostic of heavily obscured AGN, reaching into the Compton-thick regime for the highest hydrogen column densities ($N_{\rm H} > 1.5 \times 10^{24}\, {\rm cm}^{-2}$). Based on updated [O III] luminosities and intrinsic X-ray luminosities based on physical modeling of the hard X-ray spectra, we find that one galaxy was misclassified as type 2 (NGC 5005) and most of the remaining AGN are obscured, including three confirmed as Compton-thick (IC 3639, NGC 1386, and NGC 3982). One galaxy, NGC 3627, appears to be recently deactivated. Compared to the original sample the 9 AGN were selected from, this is a rate of approximately 1%. We also find a new X-ray changing-look AGN in NGC 6890.
