Understanding Quasar Outflows: Exploring the Variability of Absorption Lines in BALs

Understanding the properties of outflows in quasars, particularly BALs, is crucial and the variability of absorption lines plays an important role in this regard. Although the exact cause of such variability remains unclear, there are two mechanisms that are generally favored: gas clouds moving across the line of sight (TM scenario) and changes in ionizing flux (IC scenario). The IC scenario has been supported by some studies, such as those that have observed anti-correlations between the fractional variations of the continuum and absorption line for several samples of BAL (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.