Searching for mass-spin correlations in the population of gravitational-wave events: the GWTC-3 case study

TL;DR

This study investigates mass-spin correlations in gravitational-wave detected black hole mergers, suggesting some events may originate from dynamical formation channels, supported by Bayesian evidence from GWTC-3 data.

Contribution

The paper provides the first evidence that a subset of GWTC-3 events exhibit mass-spin correlations consistent with dynamical formation models.

Findings

Some GWTC-3 events show mass-spin correlations similar to dynamical formation.

Bayesian analysis favors models with mass-spin correlations over simpler Gaussian models.

Results support the existence of diverse formation channels for binary black holes.

Abstract

One fundamental goal of the newly born gravitational wave astronomy is discovering the origin of the observed binary black hole mergers. Towards this end, identifying features in the growing wealth of data may help in distinguishing different formation pathways. While large uncertainties still affect the binary formation models, spin-mass relations remain characteristic features of specific classes of channels. By focusing on the effective inspiral spin $\chi_\text{eff}$, the best reconstructed spin-related merger parameter, we show that current GWTC-3 data support the hypothesis that a fraction of events may display mass-spin correlations similar to one expected by dynamical formation channels of either astrophysical or primordial nature. We quantify the Bayesian evidence in favour of those models, which are substantially preferred when compared to the Gaussian phenomenological model adopted to describe the distribution of $\chi_\text{eff}$ in the recent LIGO/Virgo/KAGRA population analyses.