BHI Colloquium


Tuesday, October 22, 2019, 1:30pm to 2:30pm


BHI Meeting Room

Shane Davis (University of Virginia)

Title: Solving the Quasar "Crisis"

Abstract: 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.

Jenny Greene (Princeton University)

Title: The Search For Intermediate Mass Black Holes

Abstract: I will review the various searches and candidates for intermediate mass (10^2-10^5 Msun) black holes. I will discuss the occupation fraction of black holes and bracket the black hole mass function down to 10^4 Msun, an important input for LISA predictions.