Self-gravitating perfect-fluid tori around black holes: Bifurcations, ergoregions, and geometrical properties

TL;DR

This paper studies the geometric and physical properties of self-gravitating perfect-fluid tori around black holes, revealing bifurcations, ergoregions, and effects on orbital stability within a general-relativistic framework.

Contribution

It introduces a detailed analysis of self-gravitating tori around black holes, highlighting bifurcations, ergoregion configurations, and the influence on innermost stable circular orbits.

Findings

Identification of a parametric bifurcation in solution space

Different configurations of ergoregions including toroidal ones

Impact of torus gravity on the innermost stable circular orbit

Abstract

We investigate models of stationary, selfgravitating, perfect-fluid tori (disks) rotating around black holes, focusing on geometric properties of spacetime. The models are constructed within the general-relativistic hydrodynamics, assuming differential (Keplerian) rotation of the fluid. We discuss a parametric bifurcation occurring in the solution space, different possible configurations of ergoregions (including toroidal ergoregions associated with the tori), nonmonotonicity of the circumferential radius, as well as the impact of the torus gravity on the location of the innermost stable circular orbit.