SPS Seminar - Hunting for super-critically accreting black holes

When:  Thursday 11^th March at 14.00

Where:  Microsoft Teams - Online

Speaker:  Matt Middleton - Southampton University

Hosted by: Hugh Dickinson

Abstract:

Accretion onto black holes is widespread and – in one form or another – distributes mechanical and radiative energy into the local and distant environment. Whilst the impact of such accretion is clear, our understanding is still limited, and is most deficient at rates where the classical Eddington limit is reached. So called super-critical accretion is invoked at the highest redshifts in the most rapidly growing QSOs, in tidal disruption events, and in ultraluminous X-ray sources (ULXs). ULXs would seem to offer the chance for unparalleled insights due to their number in the local Universe and persistent brightness. However, understanding the accretion process in ULXs became somewhat more complicated with the discovery that a likely very large proportion of the underlying population contain neutron stars. This makes extrapolating to super-critically accreting SMBHs considerably harder due to the presence of a surface (!). In this talk I will discuss the progress made in studying these sources and determining their properties, and how we might use the General Relativistic effect of frame-dragging and the Lense-Thirring effect to try and locate black hole ULXs.