Evidence for Ionization-Driven BAL Variation: Anti-Correlations Between Continuum and Absorption Line Variations

Several studies have reported anti-correlations between the fractional variations of the continuum and absorption line as evidence of ionization-driven BAL variation (Lu et al. 2018; Lu & Lin 2018; Vivek 2019). However, none of these studies have compared the EW variations of BALs in different ionization states with their fractional variations of the continuum.