Evolution of relativistic thin discs with a finite ISCO stress: II. Late time behaviour

Journal article

We present solutions to the relativistic thin disc evolutionary equation using a modified description of the mean fluid flow within the disc. The model takes into account the effects of sub-circular velocities in the innermost disc regions, and resolves otherwise unsustainable behaviour present in simple finite innermost stable circular orbit (ISCO) stress disc models. We show that the behaviour of a relativistic thin disc evolving with a finite ISCO stress is comprised of three distinct stages which join the ordinarily distinct finite and vanishing ISCO stress solutions into a fully continuous model parametrization. The most important prediction of our model is the existence of an intermediate stage of ‘stalled accretion’, controlled by a single dimensionless parameter. The hallmarks of this evolutionary phase appear to have been seen in General Relativistic MHD simulations as well as in the late time X-ray observations of tidal disruption events, but dedicated simulations and extended observations are needed for a deeper understanding.

Authors: Mummery, A; Balbus, S

• Publication status: Published
• Peer review status: Peer reviewed
• Publisher: Oxford University Press
• Journal: Monthly Notices of the Royal Astronomical Society
• Volume: 489
• Issue: 1
• Pages: 143–152
• Publication date: 2019-08-05
• Acceptance date: 2019-07-31
• DOI: 10.1093/mnras/stz2142
• EISSN: 1365-2966
• ISSN: 0035-8711
• Keywords: accretion; accretion discs; turbulence; black hole physics