Gravitational waves from the Papaloizou-Pringle instability in black hole-torus systems

TL;DR

This study uses 3D general relativistic simulations to demonstrate that black hole-torus systems can develop instabilities that produce detectable quasiperiodic gravitational waves, relevant for gamma-ray bursts and supermassive black hole formation.

Contribution

First detailed simulation showing the growth of nonaxisymmetric instabilities in BH-torus systems and their gravitational wave emission.

Findings

Nonaxisymmetric instability grows in a wide range of torus models.

The instability leads to strong, quasiperiodic gravitational wave emission.

Potential observability of these gravitational waves by future detectors.

Abstract

Black hole (BH)--torus systems are promising candidates for the central engine of gamma-ray bursts (GRBs), and also possible outcomes of the collapse of supermassive stars to supermassive black holes (SMBHs). By three-dimensional general relativistic numerical simulations, we show that an $m=1$ nonaxisymmetric instability grows for a wide range of self-gravitating tori orbiting BHs. The resulting nonaxisymmetric structure persists for a timescale much longer than the dynamical one, becoming a strong emitter of large amplitude, quasiperiodic gravitational waves. Our results indicate that both, the central engine of GRBs and newly formed SMBHs, can be strong gravitational wave sources observable by forthcoming ground-based and spacecraft detectors.