Gravitational radiation from precessing accretion disks in gamma-ray bursts

TL;DR

This paper investigates the gravitational waves produced by precessing accretion disks in gamma-ray bursts, showing potential detectability by Advanced LIGO for certain disk parameters and distances.

Contribution

It provides a quantitative estimate of gravitational wave signals from precessing accretion disks in gamma-ray bursts, incorporating neutrino cooling effects.

Findings

Precession periods are estimated using an Lense-Thirring effect model.

Gravitational waves from disks smaller than 10^8 cm could be detected at less than 100 Mpc.

Precession in short gamma-ray bursts is undetectable with current technology.

Abstract

We study the precession of accretion disks in the context of gamma-ray burst inner engines. Our aim is to quantitatively estimate the characteristics of gravitational waves produced by the precession of the transient accretion disk in gamma-ray bursts. We evaluate the possible periods of disk precession caused by the Lense-Thirring effect using an accretion disk model that allows for neutrino cooling. Assuming jet ejection perpendicular to the disk plane and a typical intrinsic time-dependence for the burst, we find gamma-ray light curves that have a temporal microstructure similar to that observed in some reported events. The parameters obtained for the precession are then used to evaluate the production of gravitational waves. We find that the precession of accretion disks of outer radius smaller than $10^8$ cm and accretion rates above 1 solar mass per second could be detected by Advanced LIGO if they occur at distances of less than 100 Mpc. We conclude that the precession of a neutrino-cooled accretion disk in long gamma-ray bursts can be probed by gravitational wave astronomy. Precession of the disks in short gamma-ray events is undetectable with the current technology.