Search for Gravitational Waves from Scorpius X-1 in LIGO O3 Data With Corrected Orbital Ephemeris

TL;DR

This study re-analyzed LIGO O3 data for gravitational waves from Sco X-1 using corrected orbital parameters, confirming no detectable signals and setting upper limits on gravitational wave amplitude.

Contribution

It provides a re-analysis with corrected orbital ephemeris, reducing the search region and computational effort, and confirms null detection consistent with previous results.

Findings

No detectable gravitational wave signals found from Sco X-1.

Set upper limits on gravitational wave amplitude between 10^{-25} and 4×10^{-26}.

Reduced the search parameter space by one-third compared to previous analysis.

Abstract

Improved observational constraints on the orbital parameters of the low-mass X-ray binary Scorpius~X-1 were recently published in Killestein et al (2023). In the process, errors were corrected in previous orbital ephemerides, which have been used in searches for continuous gravitational waves from Sco~X-1 using data from the Advanced LIGO detectors. We present the results of a re-analysis of LIGO detector data from the third observing run of Advanced LIGO and Advanced Virgo using a model-based cross-correlation search. The corrected region of parameter space, which was not covered by previous searches, was about 1/3 as large as the region searched in the original O3 analysis, reducing the required computing time. We have confirmed that no detectable signal is present over a range of gravitational-wave frequencies from $25\textrm{Hz}$ to $1600\textrm{Hz}$, analogous to the null result of Abbott et al (2022). Our search sensitivity is comparable to that of Abbott et al (2022), who set upper limits corresponding, between $100\textrm{Hz}$ and $200\textrm{Hz}$, to an amplitude $h_0$ of about $10^{-25}$ when marginalized isotropically over the unknown inclination angle of the neutron star's rotation axis, or less than $4\times 10^{-26}$ assuming the optimal orientation.