The Time Variability of SDSS Stripe 82 Quasars as a Damped Random Walk

We model the time variability of 9,000 spectroscopically confirmed quasars in SDSS stripe 82 as a damped random walk. We confirm the result of Kelly et al. (2009) that this model can explain quasar light curves at an impressive fidelity level (0.01-0.02 mag). This model provides a simple statistical description of a light curve using a characteristic time scale and the amplitude of long-term variations. We search for correlations of these variability parameters with various physical parameters such as luminosity, black hole mass, and rest-frame wavelength. We acknowledge support by NSF grant AST-0807500 to the University of Washington.