8-12 juin, 2014


Monitoring Broad Absorption Line Emergence and Variability

Jesse Rogerson (York University)

Patrick B. Hall (York University), Paola Rodriguez Hidalgo (University of Toronto), W. Niel Brandt (Pennsylvania State University), Nur Filiz Ak (Pennsylvania State University/Erciyes University)

Outflows launched by the accretion disk of a supermassive black hole are important not only for understanding the physics of active galactic nuclei (AGN), but also galaxy evolution/formation. These outflows are observed as blueshifted broad absorption line (BAL) troughs in quasar spectra, and characterized as a gaseous wind accelerated outwards from the central source. The variability of BAL troughs in our observed frame is, therefore, either a result of transverse motion of absorbing clouds across our line of sight, or due to changes in the ionization of the absorbing gas. By comparing spectra from SDSS Data Release (DR) 7, DR9, and DR10, we identified multiple previously non-BAL quasars in whose spectra new absorption troughs have appeared on time scales covering 300-1200 rest-frame days. We obtained follow up Gemini/GMOS spectra of these emergent BAL quasars in order to measure how the absorption strength has since changed (timescales < 300 days in the rest-frame). I will report on our groups characterization of changes in equivalent width of these absorption troughs and the time scales on which it occurs, including one outflow traveling at v=60,000 km/s that exhibits variability on time scales of 10 days in the rest-frame.
(doit être confirmé par le SOC)