Variable Accretion Disks

We present a study of 9258 quasars observed with multi-epoch ugriz photometry with spectroscopic redshifts as part of the SDSS Southern Survey. Using a linear model to fit the spectral variations, we isolate separate spectra for the variable (disc) non-variable(disc + galaxy) components of each quasar. We find evidence for bluer spectral slopes than predicted by cannonical accretion disc theory and excellent agreement with SMC-like dust extinction. This work provides the first direct evidence to support recent groundbreaking theoretical efforts to analytically describe accretion discs in the context of General Relativity and magnetic stress.

John R. Weaver
John R. Weaver
PhD Fellow in Astrophysics

My research interests lie almost exclusively within the realm of extragalactic astrophysics and cosmology. I use state-of-the-art optical and infrared observatories and surveys to study the lives of galaxies, and how their properties change over cosmic time. This includes detailed case studies of individual galaxies, as well as statistical analyses of large survey catalogs.