Brightening of an Accretion Disk Due to Viscous Dissipation of Gravitational Waves During the Coalescence of Supermassive Black Holes

TL;DR

This paper investigates how gravitational waves from supermassive black hole mergers can heat surrounding accretion disks through viscous dissipation, potentially producing observable electromagnetic signals as counterparts to gravitational wave events.

Contribution

It introduces the concept that gravitational wave-induced viscous heating can significantly brighten accretion disks during black hole mergers, independent of accretion rate and viscosity.

Findings

GW heating exceeds accretion power beyond 10^3 Schwarzschild radii

Viscous dissipation of GWs can produce detectable EM signals

Heating effect is independent of accretion rate and viscosity coefficient

Abstract

Mergers of supermassive black hole binaries release peak power of up to ~10^57 erg/s in gravitational waves (GWs). As the GWs propagate through ambient gas, they induce shear and a small fraction of their power is dissipated through viscosity. The dissipated heat appears as electromagnetic (EM) radiation, providing a prompt EM counterpart to the GW signal. For thin accretion disks, the GW heating rate exceeds the accretion power at distances farther than 10^3 Schwarzschild radii, independently of the accretion rate and viscosity coefficient.