Vanishing Absorption and Blueshifted Emission in FeLoBAL Quasars

TL;DR

This paper investigates the variability and spectral features of FeLoBAL quasars, revealing absorption weakening, blueshifted emission lines, and possible causes like absorber motion or ionization changes.

Contribution

It provides new observations of absorption variability and blueshifted emission lines in FeLoBAL quasars, suggesting outflowing winds as the emission source.

Findings

Iron absorption strength decreases over time in studied quasars.

Blueshifted ext{MgII} and ext{FeII} lines indicate outflowing winds.

Variability may be due to absorber motion or ionization changes.

Abstract

We study the dramatic decrease in iron absorption strength in the iron low-ionization broad absorption line quasar SDSS J084133.15+200525.8. We report on the continued weakening of absorption in the prototype of this class of variable broad absorption line quasar, FBQS J140806.2+305448. We also report a third example of this class, SDSS J123103.70+392903.6; unlike the other two examples, it has undergone an increase in observed continuum brightness (at 3000~\AA\ rest-frame) as well as a decrease in iron absorption strength. These changes could be caused by absorber transverse motion or by ionization variability. We note that the \mgii\ and UV \feii\ lines in several FeLoBAL quasars are blueshifted by thousands of \kms\ relative to the \Hb\ emission line peak. We suggest that such emission arises in the outflowing winds normally seen only in absorption.