Deep exploration for continuous gravitational waves at 171--172 Hz in LIGO second observing run data

TL;DR

This paper presents a targeted search for continuous gravitational waves from neutron stars in LIGO data, achieving improved sensitivity but not detecting any signals, thus setting new constraints on neutron star deformities.

Contribution

The study introduces a novel, GPU-accelerated analysis strategy focusing on a specific parameter space, enhancing sensitivity over previous searches.

Findings

No continuous gravitational waves detected.

Sensitivity improved by 24% to 69% compared to past searches.

Constraints on neutron star deformity within theoretical maxima.

Abstract

We pursue a novel strategy towards a first detection of continuous gravitational waves from rapidly-rotating deformed neutron stars. Computational power is focused on a narrow region of signal parameter space selected by a strategically-chosen benchmark. We search data from the 2nd observing run of the LIGO Observatory with an optimised analysis run on graphics processing units. While no continuous waves are detected, the search achieves a sensitivity to gravitational wave strain of $h_0 = 1.01{\times}10^{-25}$ at 90% confidence, 24% to 69% better than past searches of the same parameter space. Constraints on neutron star deformity are within theoretical maxima, thus a detection by this search was not inconceivable.