Searches for Continuous Gravitational Waves from Supernova Remnants in the first part of the LIGO-Virgo-KAGRA Fourth Observing run

TL;DR

This paper reports on the most sensitive wide-band searches for continuous gravitational waves from 15 supernova remnants using LIGO-Virgo-KAGRA data, employing multiple pipelines and setting new upper limits.

Contribution

It introduces a comprehensive analysis of 15 supernova remnants with five pipelines, providing the most sensitive limits to date on continuous gravitational waves from these sources.

Findings

No evidence of gravitational waves detected from any source.

Set 95% confidence upper limits on strain amplitude, reaching ~4e-26 near 300 Hz.

Derived constraints on neutron star ellipticity and r-mode amplitudes.

Abstract

We present results from directed searches for continuous gravitational waves from a sample of 15 nearby supernova remnants, likely hosting young neutron star candidates, using data from the first eight months of the fourth observing run (O4) of the LIGO-Virgo-KAGRA Collaboration. The analysis employs five pipelines: four semi-coherent methods -- the Band-Sampled-Data directed pipeline, Weave and two Viterbi pipelines (single- and dual-harmonic) -- and PyStoch, a cross-correlation-based pipeline. These searches cover wide frequency bands and do not assume prior knowledge of the targets' ephemerides. No evidence of a signal is found from any of the 15 sources. We set 95\% confidence-level upper limits on the intrinsic strain amplitude, with the most stringent constraints reaching $\sim 4 \times 10^{-26}$ near 300 Hz for the nearby source G266.2$-$1.2 (Vela Jr.). We also derive limits on neutron star ellipticity and $r$-mode amplitudes for the same source, with the best constraints reaching $\lesssim 10^{-7}$ and $\lesssim 10^{-5}$, respectively, at frequencies above 400 Hz. These results represent the most sensitive wide-band directed searches for continuous gravitational waves from supernova remnants to date.