Cross-correlation search for continuous gravitational waves from a compact object in SNR 1987A in LIGO Science Run 5

TL;DR

This paper reports a search for continuous gravitational waves from SNR 1987A using LIGO data, setting new upper limits on strain and ellipticity, and validating the search methodology with simulations.

Contribution

It introduces a cross-correlation search method for gravitational waves from SNR 1987A and improves upper limits by a factor of four compared to previous results.

Findings

No gravitational waves detected within the searched frequency band.

Established a 90% confidence upper limit of h_0 ≤ 3.8×10^{-25}.

Improved strain upper limits and validated search algorithms.

Abstract

We present the results of a cross-correlation search for gravitational waves from SNR 1987A using the second year of LIGO Science Run 5 data. The frequency band 75--450\,Hz is searched. No evidence of gravitational waves is found. A 90\% confidence upper limit of $h_0 \leq 3.8\times10^{-25}$ is placed on the gravitational wave strain at the most sensitive frequency near 150\,Hz. This corresponds to an ellipticity of $\epsilon \leq 8.2\times10^{-4}$ and improves on previously published strain upper limits by a factor $\approx4$. We perform a comprehensive suite of validations of the search algorithm and identify several computational savings which marginally sacrifice sensitivity in order to streamline the parameter space being searched. We estimate detection thresholds and sensitivities through Monte-Carlo simulations.