The population of merging compact binaries inferred using gravitational waves through GWTC-3

Abstract

We report on the population properties of compact binary mergers inferred from gravitational-wave observations of these systems during the first three LIGO-Virgo observing runs. The Gravitational-Wave Transient Catalog 3 contains signals consistent with three classes of binary mergers: binary black hole, binary neutron star, and neutron star-black hole mergers. We infer the binary neutron star merger rate to be between 10 and 1700 Gpc${}^{-3}yr$^{-1}$andtheneutronstar-blackholemergerratetobebetween7.8and140Gpc$^{-3} yr${}^{-1}$, assuming a constant rate density in the comoving frame and taking the union of 90% credible intervals for methods used in this work. We infer the binary black hole merger rate, allowing for evolution with redshift, to be between 17.9 and 44 Gpc${}^{-3}$ yr${}^{-1}$ at a fiducial redshift (z=0.2). The rate of binary black hole mergers is observed to increase with redshift at a rate proportional to $(1+z{)}^{\hat{I}}º$ with $\hat{I}º=2.9_{-1.8}^{+1.7}$ for $z\lesssim 1$. Using both binary neutron star and neutron star-black hole binaries, we obtain a broad, relatively flat neutron star mass distribution extending from $1.2_{-0.2}^{+0.1}$ to $2.0_{-0.3}^{+0.3}{M}_{\odot }$. We confidently determine that the merger rate as a function of mass sharply declines after the expected maximum neutron star mass, but cannot yet confirm or rule out the existence of a lower mass gap between neutron stars and black holes. We also find the binary black hole mass distribution has localized over- and underdensities relative to a power-law distribution, with peaks emerging at chirp masses of $8.3_{-0.5}^{+0.3}$ and $27.9_{-1.8}^{+1.9}{M}_{\odot }$. While we continue to find that the mass distribution of a binary's more massive component strongly decreases as a function of primary mass, we observe no evidence of a strongly suppressed merger rate above approximately $60M_{\odot }$ [abridged]

v2: minor edits, most to Table 1 and caption; v3: rerun with public data; Data release: https://zenodo.org/record/5655785; v4: update Fig 14; v5: updated to match published version