“Solving the Quasar ‘Crisis’”

Observational constraints on the spectral shape and the sizes of quasar emission regions are in conflict with standard accretion disk models. This contrasts with disk dominated states of X-ray binaries, which seem to be reasonably consistent with theoretical predictions. This difference motivates focusing on aspects of the accretion flow that differ between these two systems and one possibility is the ultraviolet opacities present in quasars. I will present results from numerical models and simulations that suggest the enhanced opacity due to atomic transitions can have significant impact on the structure of quasar accretion flows and offer some speculation on how such effects may resolve conflicts between observation and theory.

Please note: Should you require any accommodations to ensure equal access and opportunity related to this event please contact Stacy Tiburzi at 734-764-3440 or stibu@umich.edu.

Tea will be served beforehand from 3:00-3:30pm in Serpens.