Population Properties of Compact Objects from the Second LIGO–Virgo Gravitational-Wave Transient Catalog

By The Ligo Scientific Collaboration, T. Abbott, T. Abbott, S. Abraham, F. Acernese, K. Ackley, A. Adams, C. Adams, Rana X. Adhikari, V. Adya and 1,329 more. 2020

703 citations recorded by the source corpus.

We report on the population of 47 compact binary mergers detected with a false-alarm rate of < 1yr−1 in the second LIGO–Virgo Gravitational-Wave Transient Catalog. We observe several characteristics of the merging binary black hole (BBH) population not discernible until now. First, the primary mass spectrum contains structure beyond a power law with a sharp high-mass cutoff; it is more consistent with a broken power law with a break at 39.7−9.1+20.3M⊙ or a power law with a Gaussian feature peaking at 33.1−5.6+4.0M⊙ (90% credible interval). While the primary mass distribution must extend to ∼65M⊙ or beyond, only 2.9−1.7+3.5% of systems have primary masses greater than 45M⊙ . Second, we find that a fraction of BBH systems have component spins misaligned with the orbital angular momentum, giving rise to precession of the orbital plane. Moreover, 12 %– 44 % of BBH systems have spins tilted by more than 90°, giving rise to a negative effective inspiral spin parameter, χeff . Under the assumption that such systems can only be formed by dynamical interactions, we infer that between 25% and 93% of BBHs with nonvanishing ∣χeff∣>0.01 are dynamically assembled. Third, we estimate merger rates, finding RBBH=23.9−8.6+14.3Gpc−3yr−1 for BBHs and RBNS=320−240+490Gpc−3yr−1 for binary neutron stars. We find that the BBH rate likely increases with redshift ( 85% credibility) but not faster than the star formation rate ( 86% credibility). Additionally, we examine recent exceptional events in the context of our population models, finding that the asymmetric masses of GW190412 and the high component masses of GW190521 are consistent with our models, but the low secondary mass of GW190814 makes it an outlier.

Subfields: Astronomy and Astrophysics

View Paper: https://www.semanticscholar.org/paper/6de3f709463838e136c105a4c8aaee7e705ca6a2

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In Astronomy and Astrophysics

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Citations in the corpus

• 4-OGC: Catalog of Gravitational Waves from Compact Binary Mergers (2021, methodology): “For example, we allow the maximum mass parameter mmax to vary up to 150Me compared to 100Me in the GWTC- 3 analysis (Abbott et al. 2021h).”
• Rates of compact object coalescences (2021, methodology): “Similarly, the NS-BH merger rate estimate relies on two events, GW200105 and GW200115, and is sensitive to assumptions regarding the mass distribution of such sources as well as low-number statistics (Abbott et al., 2021a).”
• GWTC-2: Compact Binary Coalescences Observed by LIGO and Virgo During the First Half of the Third Observing Run (2020, background): “In addition to BBHs, Advanced LIGO and Advanced Virgo detected the first gravitational-wave signal from a binary neutron star (BNS) coalescence, GW170817 [12], which is also the first joint detection of gravitational waves and electromagnetic emission [13,14].”
• Constraints on the Cosmic Expansion History from GWTC–3 (2021, methodology): “…BBH detections, 2 are the BNS events GW170817 (Abbott et al. 2017a) and GW190425 (Abbott et al. 2020a), 2 are the NSBH Constraints on the cosmic expansion history from GWTC–3 5 events GW200105 and GW200115 (Abbott et al. 2021) and one is the asymmetric mass binary GW190814 (Abbott et al. 2020b).”
• Evidence for Hierarchical Black Hole Mergers in the Second LIGO–Virgo Gravitational Wave Catalog (2020, methodology): “Among the GWTC-2 systems there are high-mass BBHs that have components with masses of 45 Me (Abbott et al. 2021a), the most massive being the source of GW190521 (Abbott et al. 2020b).”