Spherical-shell accretion onto the black hole–torus system

Abstract

The general relativistic hydrodynamical simulation of the spherical-shell accretion onto the stable torus around non-rotating and rotating black holes isotropically falling from a finite distance are constructed for the first time. This type of accretion might be used to explain the dynamics of the torus. The accreted matter sonically, supersonically or highly supersonically interacts with a torus and forms a newly developed dynamical structure. This spherical-shell changes the angular momentum of the torus and mediates torus instabilities which cause the termination of the torus. The impact of the rest-mass density of the perturbation is also studied which found that the high density perturbation destroys the torus in a few dynamical times. It is also found that the dumping time of the matter is much larger for the torus around a rotating black hole. On the other hand, the Papaloizou–Pringle instability from the spherical-shell accretion appears to be much more softer than the former perturbations which are called the Bondi–Hoyle accretion and accretion of the bulk of gas. The Papaloizou–Pringle instability is damped in a short time scale immediately after their formation.