Rotating black hole surrounded by self-gravitating torus in the puncture framework

Abstract

We present a formulation for computing equilibria composed of a rotating black hole and a massive self-gravitating torus in general relativity. Such a system is a plausible outcome formed after stellar core collapse of massive and supermassive stars as well as after a merger of a black hole-neutron star binary. In our formulation, the black hole is modeled in the puncture framework. The numerical solutions for equilibria are computed for rapidly rotating black holes and for a wide range of mass ratio of the black hole and torus. The equilibria obtained in this paper can be used for studying nonaxisymmetric instabilities, runaway instability, and magnetorotational instability of a self-gravitating accretion torus around a rotating black hole in numerical relativity. We also remark that the relation among the area, mass, and spin of rotating black holes are slightly modified by the torus.