Search for Gravitational Wave Bursts from Soft Gamma Repeaters

TL;DR

This paper reports on a LIGO search for gravitational waves from Soft Gamma Repeaters, setting the most stringent upper limits to date on GW amplitudes and energies associated with these astrophysical events.

Contribution

First search sensitive to neutron star f-modes from SGRs, providing the most stringent GW upper limits and constraining theoretical models.

Findings

No gravitational wave signals detected from SGR bursts.

Set upper limits on GW emission energies between 3x10^45 and 9x10^52 erg.

Established the most sensitive constraints on transient GW amplitudes to date.

Abstract

We present the results of a LIGO search for short-duration gravitational waves (GWs) associated with Soft Gamma Repeater (SGR) bursts. This is the first search sensitive to neutron star f-modes, usually considered the most efficient GW emitting modes. We find no evidence of GWs associated with any SGR burst in a sample consisting of the 27 Dec. 2004 giant flare from SGR 1806-20 and 190 lesser events from SGR 1806-20 and SGR 1900+14 which occurred during the first year of LIGO's fifth science run. GW strain upper limits and model-dependent GW emission energy upper limits are estimated for individual bursts using a variety of simulated waveforms. The unprecedented sensitivity of the detectors allows us to set the most stringent limits on transient GW amplitudes published to date. We find upper limit estimates on the model-dependent isotropic GW emission energies (at a nominal distance of 10 kpc) between 3x10^45 and 9x10^52 erg depending on waveform type, detector antenna factors and noise characteristics at the time of the burst. These upper limits are within the theoretically predicted range of some SGR models.