All-sky search for long-duration gravitational-wave bursts in the third Advanced LIGO and Advanced Virgo run

TL;DR

This paper reports a comprehensive search for long-duration gravitational-wave transients during LIGO and Virgo's third observing run, setting new sensitivity limits and finding no significant signals.

Contribution

It introduces a broad, minimally-assumptive search method for long-duration gravitational waves in the 2-500 second range, improving sensitivity over previous runs.

Findings

No significant gravitational-wave signals detected.

Sensitivity limits on gravitational-wave amplitude improved by factor of 1.8.

Established constraints on astrophysical models of long-duration transients.

Abstract

After the detection of gravitational waves from compact binary coalescences, the search for transient gravitational-wave signals with less well-defined waveforms for which matched filtering is not well-suited is one of the frontiers for gravitational-wave astronomy. Broadly classified into "short" $ \lesssim 1~$\,s and "long" $ \gtrsim 1~$\,s duration signals, these signals are expected from a variety of astrophysical processes, including non-axisymmetric deformations in magnetars or eccentric binary black hole coalescences. In this work, we present a search for long-duration gravitational-wave transients from Advanced LIGO and Advanced Virgo's third observing run from April 2019 to March 2020. For this search, we use minimal assumptions for the sky location, event time, waveform morphology, and duration of the source. The search covers the range of $2~\text{--}~ 500$~s in duration and a frequency band of $24 - 2048$ Hz. We find no significant triggers within this parameter space; we report sensitivity limits on the signal strength of gravitational waves characterized by the root-sum-square amplitude $h_{\mathrm{rss}}$ as a function of waveform morphology. These $h_{\mathrm{rss}}$ limits improve upon the results from the second observing run by an average factor of 1.8.