Search for gravitational waves from eccentric binary black holes with an effective-one-body template

TL;DR

This study conducts the first matched-filtering search for gravitational waves from eccentric binary black holes using an effective-one-body waveform model, identifying known events and setting new constraints on their event rates.

Contribution

It introduces a novel search method for eccentric BBHs with an effective-one-body model and provides the first constraints on their astrophysical event rates.

Findings

Identified 28 BBH events consistent with previous catalogs.

Reported additional candidates with moderate false alarm rates.

Set new upper limits on eccentric BBH event rates, improving sensitivity.

Abstract

As gravitational wave astronomy has entered an era of routine detections, it becomes increasingly important to precisely measure the physical parameters of individual events and infer population properties. Eccentricity is a key observable, suggesting that binaries form in a dense stellar environment through dynamical encounters. This work performs the first matched-filtering search for gravitational waves from eccentric binary black holes (BBHs) covering the mass range $[5, 200]~M_\odot$ and eccentricity at 20 Hz up to 0.5 with a newly developed effective-one-body waveform model. Throughout the third observation run of LIGO, Virgo, and KAGRA, we identify 28 BBH events with a false alarm rate below once per 100 yr; all of which were previously reported in the GWTC-3 and 4-OGC catalogs. Additional candidates with false alarm rates between once per 1 and 100 yr are also reported. We perform an injection campaign to characterize the sensitive volume time of our search pipeline. Assuming that none of the eccentric BBH events were missed by previous searches, our results provide constraints on the event rate of eccentric BBHs in the mass range [5, 30] $M_\odot$. For a 30-30 $M_\odot$ BBH with eccentricity 0.5, the event rate is limited to less than 0.06 Gpc$^{-3}$ yr$^{-1}$; this marks an order of magnitude improvement for sensitive volume compared with the previous search with a minimally modeled algorithm without using templates.