Program: GN-2013B-Q-59

Outflows from luminous AGN are important ingredients in galaxy formation. These outflows manifest as broad absorption line (BAL) troughs in quasar spectra. Trough variability can be used to constrain the physical parameters of these absorbing structures through comparison to models and simulations of accretion disk winds. Monitoring appearing/disappearing BAL troughs can constrain the distribution of BAL trough lifetimes along our line of sight. By comparing spectra from the SDSS Data Release (DR) 7 and DR 9, we identified 68 quasars in whose spectra new absorption troughs have appeared over 300-1200 restframe days, including one trough outflowing at v=60,000 km/s. We are obtaining GMOS spectra of the brightest of those quasars (33 in 2013A and 17 proposed here) to measure the absorption strength in newly appeared troughs <=300 restframe days after their previous measurement. We also propose 16 Standard ToO observations of such quasars we expect to identify in BOSS DR10 (July 2013). While we expect that some new troughs will still be strengthening, a null result of no statistical change in absorption strength would indicate a rapid onset of absorption from fast-moving, sharp-edged absorbing structures, which simulations would have to match.