The Physical Properties of Low-redshift FeLoBAL Quasars. II. the Rest-frame Optical Emission Line Properties

Authors

Karen M. Leighly, University of Oklahoma
Hyunseop Choi, University of Oklahoma
Cora Defrancesco, University of Oklahoma
Julianna Voelker, University of Oklahoma
Donald M. Terndrup, University of Oklahoma
Sarah C. Gallagher, Western University
Gordon T. Richards, Drexel University

Document Type

Article

Publication Date

8-1-2022

Journal

Astrophysical Journal

Volume

935

Issue

2

URL with Digital Object Identifier

10.3847/1538-4357/ac7e50

Abstract

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.