Three-dimensional simulations of the accretion process in Kerr space-time with arbitrary value of the spin parameter

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 vertical bar a(*)vertical bar <= 1 (black holes) and with vertical bar a(*)vertical bar > 1 (superspinars). Our full three-dimensional simulations confirm the formation of equatorial outflows for high values of vertical bar a(*)vertical bar, as found in our previous work in 2.5 dimensions. We show that the critical value of vertical bar a(*)vertical bar 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 vertical bar a(*)vertical bar <= 1 for astrophysical black hole candidates.