Search for Precessing Binary Black Holes in Advanced LIGO's Third Observing Run using Harmonic Decomposition

TL;DR

This paper presents a new harmonic decomposition method for searching precessing binary black holes in LIGO's O3 data, reducing computational costs and improving sensitivity.

Contribution

A novel search scheme that decreases filter count fivefold and enhances sensitivity by 28%, enabling scalable detection of precessing BBHs.

Findings

No new significant events detected.

Achieved 28% sensitivity improvement.

Reduced computational costs by up to 5 times.

Abstract

Binary black holes (BBHs) exhibiting spin-induced orbital precession offer unique insight into compact-binary formation channels, cosmology, and tests of general relativity. We conduct a dedicated search for precessing BBHs with unequal masses in Advanced LIGO's third observing run (O3) using the harmonic decomposition method of precessing waveforms. We introduce a novel scheme to reduce the number of filters in a harmonic search. With our new approach, our template bank requires $5\times$ fewer filters compared to another proposed precessing search in the same region. We do not find any new significant events. Our new search method achieves up to $\sim 28\%$ improvement in sensitivity and up to $5\times$ lower computational costs compared to existing precessing search pipelines. Our method enables scalable, sensitive searches for precessing BBHs in future gravitational-wave observing runs.