Black hole formation through fragmentation of toroidal polytropes

TL;DR

This paper explores a novel pathway to black hole formation via the fragmentation of differentially rotating toroidal polytropes, demonstrating the development of nonaxisymmetric instabilities leading to horizon formation.

Contribution

It is the first study to analyze the one-armed instability in full general relativity and to simulate black hole formation from toroidal polytrope fragmentation.

Findings

Toroidal polytropes are unstable to nonaxisymmetric modes.

Fragmentation leads to self-gravitating collapsing components.

A horizon forms around a collapsing fragment.

Abstract

We investigate new paths to black hole formation by considering the general relativistic evolution of a differentially rotating polytrope with toroidal shape. We find that this polytrope is unstable to nonaxisymmetric modes, which leads to a fragmentation into self-gravitating, collapsing components. In the case of one such fragment, we apply a simplified adaptive mesh refinement technique to follow the evolution to the formation of an apparent horizon centered on the fragment. This is the first study of the one-armed instability in full general relativity.