Analyzing the Variability of Low-ionization Broad Absorption Line Quasars: Evidence for Transiting Absorbers

Of course, we cannot disregard the possibility of transiting being the reason for some of these loBALs. From our statistical sample, we are unable to determine the exact cause of each absorption variation. To fully understand the interpretation of the variation in the loBALs within our sample, it is necessary to carefully analyze the spectra of each individual source. For instance, in cases where saturated BALs exhibit disappearing or emerging phenomena, this can provide strong evidence for a transiting scenario (McGraw 2017...). This is because fluctuations in the ionizing radiation field are unlikely to induce changes in absorbers that have high optical depths. On the other hand, if BALs demonstrate re-emerging phenomena or coordinated variations across a broad range of velocities (e.g., exceeding 10,000 km s−1), it is more plausible to attribute these changes to alterations in ionization rather than transverse motion scenarios (McGraw 2017 and references therein...). However, the specific analysis of absorption lines in individual spectra falls beyond the scope of this study.