GWTC-2: Compact Binary Coalescences Observed by LIGO and Virgo During the First Half of the Third Observing Run

Abstract

UTC. By imposing a false-alarm-rate threshold of two per year in each of the four search pipelines that constitute our search, we present 39 candidate gravitational wave events. At this threshold, we expect a contamination fraction of less than 10%. Of these, 26 candidate events were reported previously in near real-time through GCN Notices and Circulars; 13 are reported here for the first time. The catalog contains events whose sources are black hole binary mergers up to a redshift of ∼ 0.8, as well as events which could plausibly originate from binary neutron stars, neutron star-black hole binaries, or binary black holes. For the latter group, we are unable to determine the nature based on estimates of the component masses and spins from gravitational wave data alone. The range of candidate events which are unambiguously identified as binary black holes (both objects ≥ 3 M ) is increased compared to GWTC-1, with total masses from ∼ 14M for GW190924 021846 to ∼ 150M for GW190521. For the first time, this catalog includes binary systems with asymmetric mass ratios, which had not been observed in data taken before April 2019. Given the increased sensitivity of Advanced LIGO and Advanced Virgo, the detection of 39 candidate events in ∼26 weeks of data (∼1.5 per week) is consistent with GWTC-1.

Ancestral Black Holes of Binary Merger GW190521

“…Integrals involving M k were approximated as Monte Carlo integrals. For the prior probability π(m 1 , m 2 ) we adopted the average over the posterior population distribution of the model fit on the GWTC-2 gravitational wave catalog (power law + peak model; Abbott et al 2021). This model takes into account the mass distributions for both black holes, including the correlation between them Talbot & Thrane 2018.…”

The GW-Universe Toolbox II: constraining the binary black hole population with second and third generation detectors

“…The era of gravitational wave (GW) astronomy has begun with the first detection of a binary black hole (BBH) merger in 2015 (Abbott et al 2016). There have been ∼ 90 BBH systems discovered with ∼ 3 years observation in the LIGO/Virgo O1/O2/O3 runs (GWTC-1&2 catalogues: Abbott et al (2019Abbott et al ( , 2020). The number is catching up on that of the discovered Galactic black holes (BH) in Xray binaries during the last half century (Corral-Santana et al 2016).…”

Partial-envelope stripping and nuclear-timescale mass transfer from evolved supergiants at low metallicity

“…Similarly, Type Ic supernovae with broad lines in the spectra are typically found in metal-poor hosts, whereas normal Type Ic supernovae avoid dwarf galaxies (Modjaz et al 2011). It has been suggested that BHs with masses above ∼ 30 M , frequently found in binary BH mergers detected in GW by LIGO/Virgo (Abbott et al 2020), may originate from metal-poor environments, where the reduced strength of line-driven winds allows for the formation of more massive BHs (e.g. Belczynski et al 2010;Vink et al 2021).…”