Modelling the AGN broad-line region using single-epoch spectra − II. Nearby AGNs
Modelling the AGN broad-line region using single-epoch spectra − II. Nearby AGNs
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DOI：
10.1093/mnras/staa285
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发表时间：
2019-09
影响因子：
4.8
通讯作者：
S. Raimundo;M. Vestergaard;M. Vestergaard;M. Goad;C. Grier;P. Williams;B. Peterson;B. Peterson;T. Treu
中科院分区：
文献类型：
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作者：
S. Raimundo;M. Vestergaard;M. Vestergaard;M. Goad;C. Grier;P. Williams;B. Peterson;B. Peterson;T. Treu
宽线区域（BLR）的结构是确定活动星系核（AGN）维里黑洞质量的重要组成部分，这对研究黑洞在星系演化中的作用具有重要意义。对BLR几何和动力学的限制可以从使用混响映射数据（即监测数据）的速度分辨研究中获得。然而，监测数据在观测上是昂贵的，并且只能用于agn的有限样本，主要局限于局部宇宙。在这里，我们探索了贝叶斯推理的一个新版本，即BLR的物理模型，该模型使用单个光谱和来自半径-光度关系的BLR大小的先验信息，来模拟AGN BLR的几何和动力学。我们将我们的模型应用于11个agn样本，这些agn之前已经使用监测数据建模。我们的单历元BLR模型能够用推断的参数值约束一些BLR参数，这些参数值在不确定性范围内与监测数据建模确定的参数值一致。我们发现，我们的模型能够对具有宽发射线的agn的BLR推导出更强的约束，这些agn定性地具有更多的子结构和更多的不对称性，可能是因为它们包含更多的信息来约束物理模型。该模型的性能使其成为一种实用且具有成本效益的工具，可用于确定大量低红移和高红移agn样本的一些BLR特性，这些样本无法获得监测数据。
The structure of the broad-line region (BLR) is an essential ingredient in the determination of active galactic nucleus (AGN) virial black hole masses, which in turn are important to study the role of black holes in galaxy evolution. Constraints on the BLR geometry and dynamics can be obtained from velocity-resolved studies using reverberation mapping data (i.e. monitoring data). However, monitoring data are observationally expensive and only available for a limited sample of AGNs, mostly confined to the local Universe. Here, we explore a new version of a Bayesian inference, physical model of the BLR that uses an individual spectrum and prior information on the BLR size from the radius–luminosity relation, to model the AGN BLR geometry and dynamics. We apply our model to a sample of 11 AGNs, which have been previously modelled using monitoring data. Our single-epoch BLR model is able to constrain some of the BLR parameters with inferred parameter values that agree within the uncertainties with those determined from the modelling of monitoring data. We find that our model is able to derive stronger constraints on the BLR for AGNs with broad emission lines that qualitatively have more substructure and more asymmetry, presumably as they contain more information to constrain the physical model. The performance of this model makes it a practical and cost-effective tool to determine some of the BLR properties of a large sample of low- and high-redshift AGNs, for which monitoring data are not available.