Observationally constraining gravitational wave emission from short gamma-ray burst remnants

TL;DR

This paper uses X-ray observations of short gamma-ray burst remnants to constrain the properties of the newborn neutron stars and set upper limits on their gravitational wave emissions, indicating detection is unlikely soon.

Contribution

It introduces a novel method to constrain neutron star properties and gravitational wave emission using only X-ray light curves of short gamma-ray burst remnants.

Findings

Neutron star ellipticity constrained by X-ray data

Upper limits on gravitational wave emission established

Detection prospects with current interferometers are low

Abstract

Observations of short gamma-ray bursts indicate ongoing energy injection following the prompt emission, with the most likely candidate being the birth of a rapidly rotating, highly magnetised neutron star. We utilise X-ray observations of the burst remnant to constrain properties of the nascent neutron star, including its magnetic field-induced ellipticity and the saturation amplitude of various oscillation modes. Moreover, we derive strict upper limits on the gravitational wave emission from these objects by looking only at the X-ray light curve, showing the burst remnants are unlikely to be detected in the near future using ground-based gravitational wave interferometers such as Advanced LIGO.