The Presence of P V BAL as a Diagnostic for Variability in Saturated C IV BALs

For example, the detection of clear variability in a saturated C IV BAL provides evidence in favor of the transiting scenario. This is because a highly saturated C IV BAL is not easily affected by small changes in ionization, but can easily exhibit variations due to the transiting of outflows (McGraw et al. 2018). The presence of a P V BAL can serve as a detector for saturated C IV BALs that show obvious variability. This is because the existence of a P V BAL indicates that the corresponding C IV BAL is highly saturated (Capellupo 2014, 2017, McGraw et al. 2018).