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arXiv · 2205.12946

The Physical Properties of Low-Redshift FeLoBAL Quasars: II. The Rest-Frame Optical Emission Line Properties

Karen M. Leighly·Hyunseop Choi·Cora DeFrancesco·Julianna Voelker·Donald M. Terndrup·Sarah C. Gallagher·Gordon T. Richards
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Abstract

We report the results of analysis of the Hbeta emission-line region of a sample of thirty 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 [OIII] and FeII emission (Boroson & Green 1992). 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-BAL quasars are consistent, and therefore the difference in the Hbeta region emission between FeLoBAL quasars and unabsorbed quasars is a new result. The two populations of FeLoBAL quasars are characterized by low and high bolometric luminosities and Eddington ratios. Some previous studies have suggested that BAL quasars 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 Hbeta FWHM is systematically broader among the FeLoBALQs compared with the non-BAL quasars implying a higher inclination viewing angle or a dearth of low-velocity line-emitting gas.

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Karen M. Leighly, Hyunseop Choi, Cora DeFrancesco, Julianna Voelker, Donald M. Terndrup, Sarah C. Gallagher, Gordon T. Richards. 2022-05-25. The Physical Properties of Low-Redshift FeLoBAL Quasars: II. The Rest-Frame Optical Emission Line Properties. https://doi.org/10.3847/1538-4357%2Fac7e50

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