Astronomy Colloquium Series

Super Eddington Black Hole Accretion Flows

Super Eddington accretion occurs in many systems, such as the inner
regions of quasars and luminous AGN, ultra-luminous X-ray sources
(ULXs), and tidal disruption events. Understanding such flows is
important not only for interpreting the spectra and variability of
these sources, but also to predict the rate of growth of black holes
in the early universe, and to quantify energy and momentum feedback
into the medium surrounding the black hole, a process likely to be
important in controlling galaxy formation in the case of AGN. New
results from a study of the magnetohydrodynamics of luminous accretion
flows, in which radiation pressure dominates, will be presented.
We have developed new numerical methods based on a formal solution
of the time-dependent radiation transfer equations to study this
regime. Our numerical simulations reveal new effects that require
extension of standard thin-disk models. We discuss these results,
and their implications for the astrophysics of accreting black
holes.