Search for continuous gravitational waves from unknown neutron stars in binary systems with long orbital periods in O3 data

TL;DR

This study conducted a sensitive all-sky search for continuous gravitational waves from unknown neutron stars in binary systems with long orbital periods using O3 data, setting new upper limits and improving search sensitivity.

Contribution

The paper introduces an enhanced search pipeline that is 75% more sensitive than previous methods, covering a previously unexplored parameter space of binary neutron star systems.

Findings

No gravitational wave signals detected.

Set upper limits on gravitational-wave amplitudes.

Improved sensitivity by 75% over previous searches.

Abstract

Gravitational waves emitted by asymmetric rotating neutron stars are the primary targets of continuous gravitational-wave searches. Neutron stars in binary systems are particularly interesting due to the potential for non-axisymmetric deformations induced by a companion star. However, all-sky searches for unknown neutron stars in binary systems are very computationally expensive and this limits their sensitivity and/or breadth. In this paper we present results of a search for signals with gravitational-wave frequencies between $50$ and $150$~Hz, from systems with orbital periods between $100$ and $1\,000$ days and projected semi-major axes between $40$ and $200$~light-seconds. This parameter-space region has never been directly searched before. We do not detect any signal, and our results exclude gravitational-wave amplitudes above $1.25 \times 10^{-25}$ at $144.32$~Hz with $95\%$ confidence. Our improved search pipeline is more sensitive than any previous all-sky binary search by about $75\%$.