Choked accretion onto a Kerr black hole

Abstract

The choked accretion model consists of a purely hydrodynamical mechanism in which, by setting an equatorial to polar density contrast, a spherically symmetric accretion flow transitions to an inflow-outflow configuration. This scenario has been studied in the case of a (non-rotating) Schwarzschild black hole as central accretor, as well as in the non-relativistic limit. In this article, we generalize these previous works by studying the accretion of a perfect fluid onto a (rotating) Kerr black hole. We first describe the mechanism by using a steady-state, irrotational analytic solution of an ultrarelativistic perfect fluid, obeying a stiff equation of state. We then use hydrodynamical numerical simulations in order to explore a more general equation of state. Analyzing the effects of the black hole's rotation on the flow, we find in particular that the choked accretion inflow-outflow morphology prevails for all possible values of the black hole's spin parameter, showing the robustness of the model.