Variability in Quasar Broad Absorption Line Outflows
  Broad absorption lines (BALs) in quasar spectra identify high velocity outflows that likely exist in all quasars and could play a major role in feedback to galaxy evolution. Studying the variability in these BALs can help us understand the structure, evolution, and basic physical properties of these outflows. We are conducting a BAL monitoring program, which so far includes 163 spectra of 24 luminous quasars, covering time-scales from \sim 1 week to 8 years in the quasar rest-frame. We investigate changes in both the CIV {\lambda}1550 and SiIV {\lambda}1400 BALs, and we report here on some of the results from this program. 
Daniel M. Capellupo, Fred Hamann, Joseph C. Shields, Jules Halpern,   Paola Rodr\'iguez Hidalgo, Tom A. Barlow
astro-ph.CO