The Physical Properties of Low-redshift FeLoBAL Quasars. II. The Rest-frame Optical Emission Line Properties
The Physical Properties of Low-redshift FeLoBAL Quasars. II. The Rest-frame Optical Emission Line Properties
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DOI：
10.3847/1538-4357/ac7e50
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发表时间：
2022-05
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影响因子：
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通讯作者：
K. Leighly;Hyunseop Choi;Cora DeFrancesco;J. Voelker;D. Terndrup;S. Gallagher;G. Richards
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作者：
K. Leighly;Hyunseop Choi;Cora DeFrancesco;J. Voelker;D. Terndrup;S. Gallagher;G. Richards
我们报告了 30 个低红移 (z < 1) 铁低电离宽吸收线类星体 (FeLoBALQ) 样本的 Hβ 发射线区域的分析结果。其中 11 个物体被新分类为 FeLoBALQ。并行分析了 132 个未吸收类星体的匹配样本。发射线显示出 [O iii] 和 Fe ii 发射之间众所周知的反相关性。使用称为 E1 的汇总统计量来量化这种反相关性，我们发现虽然未吸收类星体的 E1 分布具有单峰，但 FeLoBALQ 在此参数中具有双峰形状。先前的研究表明，BAL 和非 BALQ 的线发射特性是一致的；因此，FeLoBALQs和未吸收类星体之间Hβ区域发射的差异是一个新的结果。 FeLoBALQ 的两个群体的特点是低和高辐射光度和爱丁顿比率。之前的一些研究表明BALQ是高吸积率天体，因此FeLoBAL类星体低吸积率分支的发现是出乎意料的。我们还发现 FeLoBALQ 中的 Hβ FWHM 系统地更宽，这意味着具有更高的倾斜视角或缺乏低速线发射气体。
We report the results of an analysis of the Hβ emission line region of a sample of 30 low-redshift (z < 1) iron low-ionization broad absorption line quasars (FeLoBALQs). Eleven of these objects are newly classified as FeLoBALQs. A matched sample of 132 unabsorbed quasars was analyzed in parallel. The emission lines showed the well-known anticorrelation between the [O iii] and Fe ii emission. Using a summary statistic called E1 to quantify this anticorrelation, we found that while the distribution of E1 for the unabsorbed quasars has a single peak, the FeLoBALQs have a bimodal shape in this parameter. Previous studies have shown that the line emission properties of BAL and non-BALQs are consistent; therefore, the difference in the Hβ region emission between FeLoBALQs and unabsorbed quasars is a new result. The two populations of FeLoBALQs are characterized by low and high bolometric luminosities and Eddington ratios. Some previous studies have suggested that BALQs are high accretion rate objects and therefore the discovery of the low accretion rate branch of FeLoBAL quasars was unexpected. We also found that the Hβ FWHM is systematically broader among the FeLoBALQs, implying a higher inclination viewing angle or a dearth of low velocity line emitting gas.