Results from high-frequency all-sky search for continuous gravitational waves from small-ellipticity sources

TL;DR

This paper reports a highly sensitive all-sky search for continuous gravitational waves from neutron stars with very small ellipticity, using advanced analysis pipelines on LIGO data, setting new upper limits and identifying potential outliers.

Contribution

It introduces a new analysis pipeline and demonstrates a significant sensitivity improvement over previous searches for high-frequency gravitational waves from neutron stars.

Findings

No confirmed detections, but new outliers identified.

Set upper limits excluding neutron stars with ellipticity 1e-8 within 65 pc.

Achieved over 5-fold sensitivity improvement over prior work.

Abstract

We present the results of an all-sky search for continuous gravitational wave signals with frequencies in the 1700-2000 Hz range from neutron stars with ellipticity of 1e-8. The search employs the Falcon analysis pipeline [citation 5] on LIGO O2 public data. Our results improve by a factor greater than 5 over [citation 11]. This is a huge leap forward: it takes an entirely new generation of gravitational wave detectors to achieve a 10-fold sensitivity increase over the previous generation [citation 12]. Within the probed frequency range and aside from the detected outliers, we can exclude neutron stars with ellipticity of 1e-8 within 65 pc of Earth. We set upper limits on the gravitational wave amplitude that hold even for worst-case signal parameters. New outliers are found, some of which we are unable to associate with any instrumental cause. If any were associated with a rotating neutron star, this would likely be the fastest neutron star today.