Non-axisymmetric relativistic Bondi-Hoyle accretion on to a Kerr black hole

Abstract

In our programme of studying numerically the so-called BondiHoyle accretion in the fully relativistic regime, we present here the rst results concerning the evolution of matter accreting supersonically on to a rotating (Kerr) black hole. These computations generalize previous results where the non-rotating (Schwarzschild) case was extensively considered. We parametrize our initial data by the asymptotic conditions for the uid and explore the dependence of the solution on the angular momentum of the black hole. Towards quantifying the robustness of our numerical results, we use two different geometrical foliations of the black hole spacetime, the standard form of the Kerr metric in BoyerLindquist coordinates as well as its KerrSchild form, which is free of coordinate singularities at the black hole horizon. We demonstrate some important advantages of using such horizon-adapted coordinate systems.