论文标题
咖啡馆项目：活动星系中的光学Fe II和近红外CA II三胞胎发射 - 模拟EWS，云尺寸的共依赖性和金属含量
The CaFe Project: Optical Fe II and Near-Infrared Ca II triplet emission in active galaxies -- simulated EWs, the co-dependence of cloud sizes and metal content
论文作者
论文摘要
在活性银河核中建模低电离线（LIL）仍然面临着解释观察到的等效宽度（EWS）的问题。我们使用光电代码云量检查了光学Fe II和近红外CA II三元组（CAT）发射强度。使用I ZW 1的事件连续性 - 典型的1型窄线seyfert Galaxy，我们可以恢复光学Fe II的线比（即R $ _ {\ rm {\ rm {fe ii}} $）和Nir Cat（即R $ _ {\ r $ _ {\ rm {\ rm {cat} $），以估算。虽然，不幸的是，（u，$ \ rm {n_ {h}} $）复制了符合线比的对，但不幸的是，与可满足的线EWS无关。因此，我们提出，BLR云的LIL区域没有看到从积聚磁盘中散发出的遥远观察者看到的连续体，而是看到原始连续体的过滤版本。作为BLR辐照的来源，过滤连续体的假设恢复了LIL物种的现实EWS。但是，我们的研究发现，要考虑到足够的r $ _ {\ rm {fe ii}} $（fe ii/h $β$ flux比率）发射，必须在铁中选择性地过多地量。另一方面，r $ _ {\ rm {cat}} $（cat/h $β$通量比）发射范围从太阳能到超值金属的范围更大。在所有这些模型中，发现BLR云密度与我们先前工作的结论一致，即$ \ rm {n_ {h}} \ sim 10^{12} $ cm $^{ - 3} $。此处获得的一个有趣的结果是，当调用微扰动性时，金属度的值将金属度的值降低到r $ _ {\ rm {fe ii}} $情况下的因子10，这表明微型扰动可以作为Fe II的明显金属控制器。相反，r $ _ {\ rm {cat}} $ case不受微扰动的效果的影响。
Modelling the low ionization lines (LIL) in active galactic nuclei still faces problems in explaining the observed equivalent widths (EWs). We examine the optical Fe II and near-infrared Ca II triplet (CaT) emission strengths using the photoionization code CLOUDY. Using an incident continuum for I Zw 1 - a prototypical Type-1 narrow-line Seyfert galaxy, we can recover the line ratios for the optical Fe II (i.e. R$_{\rm{Fe II}}$) and the NIR CaT (i.e. R$_{\rm{CaT}}$) in agreement to the observed estimates. Although, the pairs of (U,$\rm{n_{H}}$) that reproduce the conforming line ratios, unfortunately, do not relate to agreeable line EWs. We thus propose that the LIL region of the BLR cloud doesn't see the same continuum seen by a distant observer that is emanated from the accretion disk, rather it sees a filtered version of the original continuum. The assumption of the filtered continuum as the source of BLR irradiation recovers realistic EWs for LIL species. However, our study finds that to account for the adequate R$_{\rm{Fe II}}$ (Fe II/H$β$ flux ratio) emission, the BLR needs to be selectively overabundant in iron. On the other hand, the R$_{\rm{CaT}}$ (CaT/H$β$ flux ratio) emission spans a broader range from solar to super-solar metallicities. In all these models the BLR cloud density is found to be consistent with our conclusions from prior works, i.e. $\rm{n_{H}} \sim 10^{12}$ cm$^{-3}$. An interesting result obtained here is the reduction in the value of the metallicity by up to a factor 10 for the R$_{\rm{Fe II}}$ cases when the microturbulence is invoked, suggesting that microturbulence can act as an apparent metallicity controller for the Fe II. On the contrary, the R$_{\rm{CaT}}$ cases are rather unaffected by the effect of microturbulence.
