Detection of Gravitational Wave Emission by Supermassive Black Hole Binaries Through Tidal Disruption Flares

TL;DR

This paper demonstrates that tidal disruption events in supermassive black hole binaries produce periodic signals modulated by relativistic effects, enabling detection of gravitational wave-driven orbital decay through long-term monitoring.

Contribution

It introduces a method to detect gravitational wave emission from supermassive black hole binaries via periodic tidal disruption flare signals.

Findings

Gas streams form accretion disks around both black holes.

Light curves are modulated over the binary orbital period.

Detection of orbital decay is possible through long-term observation of tidal disruption events.

Abstract

Galaxy mergers produce supermassive black hole binaries, which emit gravitational waves prior to their coalescence. We perform three-dimensional hydrodynamic simulations to study the tidal disruption of stars by such a binary in the final centuries of its life. We find that the gas stream of the stellar debris moves chaotically in the binary potential and forms accretion disks around both black holes. The accretion light curve is modulated over the binary orbital period owing to relativistic beaming. This periodic signal allows to detect the decay of the binary orbit due to gravitational wave emission by observing two tidal disruption events that are separated by more than a decade.