2026/05/26 by The LIGO Scientific Collaboration, the Virgo Collaboration, the KAGRA Collaboration +1813 · 2 voices · 3 citations
#astro-ph.HE #gr-qc
We present the population properties of merging compact binaries inferred using 267 mergers from the cumulative Gravitational-Wave Transient Catalog 5.0. As this data set contains no new sources with a neutron star, we primarily focus on the properties of the binary black hole mergers. We infer the merger rate of binary black holes with component masses between 2.5 M_\odot and 200 M_\odot to be 27.5-- 49.4 Gpc-3 yr-1 (all intervals at 90% credible levels) at redshift z = 0.2. We find evidence for a subpopulation of binary black hole mergers that host a rapidly spinning black hole (dimensionless spins χ∼ 0.7), consistent with signatures of hierarchical mergers. We find that these occur at two mass scales, the first at primary masses ∼ 10--20 M_\odot and the second above ∼ 45 M_\odot , and we estimate their total rate at z=0.2 to be 0.2-- 3.11 \rm Gpc-3 \rm yr-1. We infer that, above 40 M_\odot , the mass distribution of the less massive (secondary) black hole declines more steeply than that of the more massive (primary) one. This is consistent with a flatter mass-ratio distribution and indicates the prevalence of unequal-mass binaries with large primary masses. We find evidence for two features in the black hole mass spectrum: a peak around 10 M_\odot and a change of slope at around 35 M_\odot . Black holes of ∼ 35 M_\odot pair preferentially with companions of similar mass. Additionally, we find that the effective inspiral spin distribution of binary black holes is asymmetric about zero, based on which we infer that at least 9 % of mergers occur in channels with some preference for spin-orbit alignment. We find evidence that...