Transit Events as a Potential Cause for Variability in loBALs

Certainly, we cannot ignore the possibility that transit events may be responsible for the variations observed in some of these loBALs. For example, the presence of a P V BAL indicates that the C IV BAL is highly saturated, as evidenced by the C IV/P V optical depth ratio being greater than ∼100. This finding is supported by studies conducted by Hamann (1998), Leighly et al. (2009), Leighly, Dietrich & Barber (2011), and Borguet et al. (2012). Expanding on these findings, Capellupo et al. (2014) argue that the variability observed in the P V and saturated C IV BALs strongly supports the transit scenario.