Accretion disks - What do we know about them?

Abstract

This essay briefly describes the present status of research on accretion disks around compact objects - in particular, blackholes - covering both the thin and thick disks. Significant results from various analyses regarding the structure and stability of such disks are presented. It is pointed out that the magnetic field has a very important role to play in the disk structure as it contributes mainly to the turbulent viscosity which has a primary role in the dynamics of disks. Attention is drawn to the fact that a fully detailed analysis of accretion disks should take into account selfconsistent electromagnetic field, which could get enhanced because of spacetime curvature effects, in a fully general relativistic treatment.