SiIV and NV absorption line SDSS quasar systems

We obtain 50 variable Si IV absorption line systems and 39 variable N V absorption line systems. We find that the variations in most of the C IV, Si IV, and N V absorption lines are correlated with the changes in quasar continuum.

In addition, a significant portion of the variable absorption lines are the consistent variations of multiple systems with large velocity separations. Therefore, the variations of the C IV, Si IV, and N V absorption lines could be mainly driven by the changes in quasar radiations, which cause changes in ionization states or column densities of absorbing gas. We also find that the variable C IV, Si IV, and N V absorption line systems can be divided into low-ionization systems and high-ionization systems.