3D simulations of the accretion process in Kerr space-time with arbitrary value of the spin parameter

Abstract

We present the results of three-dimensional general relativistic hydrodynamic simulations of adiabatic and spherically symmetric accretion in Kerr space-time. We consider compact objects with spin parameter $|a_*| \le 1$ (black holes) and with $|a_*| > 1$ (super-spinars). Our full three-dimensional simulations confirm the formation of equatorial outflows for high values of $|a_*|$, as found in our previous work in 2.5 dimensions. We show that the critical value of $|a_*|$ determining the onset of powerful outflows depends mainly on the radius of the compact object. The phenomenon of equatorial outflows can hardly occur around a black hole and may thus be used to test the bound $|a_*| \le 1$ for astrophysical black hole candidates.