The shocks during the accretion of an ultrarelativistic supersonic gas onto a rotating black hole

摘要

In this work, we track the evolution of an ultrarelativistic fluid onto aKerr black hole, on the equatorial plane. In this treatment, we consider thelimit where the rest mass density is neglected, that is, the approximation isvalid in the regime where the internal energy dominates over the rest massdensity. We particularly concentrate in the case of a gas with $\Gamma$ = 4/3,which corresponds to a radiation fluid. We show, as in several cases, that ashock cone appears when the asymptotic velocity of the fluid is larger than theasymptotic relativistic sound speed of the gas. On the other hand, in order toshow the system approaches to steady state, we calculate the accreted totalenergy rate on a spherical surface. Finally, we also show the gas distributionand various of its properties.