About the project
Compact objects (neutron stars and black holes) can accrete material through a disc which is bright across the EM spectrum. There is good theoretical and observational evidence that the accretion disc will be misaligned with the spin axis of the compact object; the resulting general relativistic effect of frame dragging leads to Lense-Thirring torques which can cause the accretion disc to precess (wobble vertically and radially). At extreme rates of accretion such as those found in tidal disruption events, ultraluminous X-ray sources and both local and high redshift AGN, the disc changes considerably, expanding and losing material via a wind. It has been suggested that super-Eddington discs/winds will also precess, giving rise to characteristic variability, the timescale of which encodes key information about the compact object.
The student will develop new time-dependent analytical models for precessing super-Eddington discs in both AGN and X-ray binaries and apply these to data coming from X-ray satellite missions.
