论文标题
宽发射线和X射线频谱的共同进化
Coevolution of broad emission lines and X-ray spectrum in changing-look AGNs
论文作者
论文摘要
更换活跃的银河系核（锁骨）显示了几年内宽发射线的消失和重新出现，这挑战了基于方向的AGN统一模型。我们减少了五个经过良好研究的锁骨的X射线数据，在过去的几十年中，它们显示出广泛的排放线的强烈变化。我们发现，X射线光子指数，$γ$和Eddington标准的X射线光度，$ L _ {\ rm 2-10 kev}/l _ {\ rm EDD} $，通常遵循负相关和正相关，当Eddington比率较低且高于$ \ sim sim sim sim sim 10^$ sim sim sim 10^$ sim sim 10^$ sim sim sim sim sim sim sim sim sim sim sim cop时。我们发现，观察到的较宽H $β$排放线的锁骨保持在$γ-L _ {\ rm 2-10 keV}/l _ {\ rm edd} $相关性的积极部分，而广泛的h $β$线在$γ-l _ {\γ-l _ {\ rm 2-10 kever的一部分中变得虚弱或消失。 EDD} $相关性，这表明宽线的演变应与基础吸积过程的演变相关。我们进一步发现，锁骨与$ l _ {\ rm bol} -l _ {\ rm bol}/l _ {\ rm edd} $相关性的其他不同类型的AGN一致。这些结果支持锁骨属于具有辐射测定比率$ \ sim $ 1 \％的AGN的特殊阶段，其中宽发射线很容易受到增生模式过渡引起的电离亮度的强烈变化。
Changing-look active galactic nuclei (CLAGNs) show the disappearance and reappearance of broad emission lines in a few years, which challenges the orientation-based AGN unification model. We reduce the X-ray data for five well-studied CLAGNs that show a strong change in broad emission lines in the past several decades. We find that the X-ray photon index, $Γ$, and the Eddington-scaled X-ray luminosity, $L_{\rm 2-10 keV}/L_{\rm Edd}$, normally follow negative and positive correlations when the Eddington ratio is lower and higher than a critical value of $\sim 10^{-3}$. We find that the CLAGNs observed with broad H$β$ emission lines stay in the positive part of the $Γ-L_{\rm 2-10 keV}/L_{\rm Edd}$ correlation, while the broad H$β$ lines become weak or disappear in the anticorrelation part of the $Γ-L_{\rm 2-10 keV}/L_{\rm Edd}$ correlation, which suggests that the evolution of the broad lines should be correlated with the evolution of the underlying accretion process. We further find that the CLAGNs are consistent with the other different types of AGNs in the $L_{\rm bol}-L_{\rm bol}/L_{\rm Edd}$ correlation. These results support that the CLAGNs are belong to a special stage of AGNs with a bolometric Eddington ratio $\sim$1\%, where the broad emission lines are easily affected by the strong variation in ionization luminosity that is caused by the transition of accretion modes.
