Accretion discs around Kerr black holes and tidal disruption events – Prof Steven Balbus

This talk was part of the UH Centre for Astrophysics Research (CAR) 2023-2024 seminar series. For the ongoing programme, please see: https://www.herts.ac.uk/research/cent...

Date: 27 Mar 2024
Speaker: Prof Steven Balbus – University of Oxford
Title: Time dependent accretion discs around Kerr black holes and tidal disruption events

Abstract: I will discuss an evolutionary equation for thin accretion discs in general relativity, and apply its solutions to late time tidal disruption event observations. Much of the analysis may be done analytically. Both the optical/UV and the X-ray bands may be fit simultaneously with a single evolving disc model. Both bands are very distinctive, so this is powerful evidence for a late time disc being present. The fitting can be automated for a large number of sources, and central black hole properties deduced, providing a new diagnostic for both black hole populations and indirectly for faint galaxies. Time permitting, I will also discuss a novel class of simple and astrophysicaly interesting orbits within the innermost stable circular orbit, which have recently been discovered and identified in full GR MHD simulations.