Authors

R. Abbott, California Institute of Technology
T. D. Abbott, Louisiana State University
S. Abraham, Inter-University Centre for Astronomy and Astrophysics India
F. Acernese, Università degli Studi di Salerno
K. Ackley, Monash University
A. Adams, Christopher Newport University
C. Adams, LIGO Livingston
R. X. Adhikari, California Institute of Technology
V. B. Adya, The Australian National University
C. Affeldt, Max Planck Institute for Gravitational Physics (Albert Einstein Institute)
M. Agathos, University of Cambridge
K. Agatsuma, University of Birmingham
N. Aggarwal, Northwestern University
O. D. Aguiar, Instituto Nacional de Pesquisas Espaciais
L. Aiello, Gran Sasso Science Institute
A. Ain, Istituto Nazionale di Fisica Nucleare, Sezione di Pisa
P. Ajith, Tata Institute of Fundamental Research, Mumbai
S. Akcay, Friedrich-Schiller-Universität Jena
G. Allen, University of Illinois Urbana-Champaign
A. Allocca, Istituto Nazionale di Fisica Nucleare, Sezione di Pisa
P. A. Altin, The Australian National University
A. Amato, Université Claude Bernard Lyon 1
S. Anand, California Institute of Technology
A. Ananyeva, California Institute of Technology
S. B. Anderson, California Institute of Technology
W. G. Anderson, University of Wisconsin-Milwaukee
S. V. Angelova, University of Strathclyde
S. Ansoldi, Università degli Studi di Udine
J. M. Antelis, Embry-Riddle Aeronautical University, Prescott
S. Antier, Université de Paris
S. Appert, California Institute of Technology
K. Arai, California Institute of Technology
M. C. Araya, California Institute of Technology

Document Type

Article

Publication Date

6-1-2021

Abstract

We report on gravitational-wave discoveries from compact binary coalescences detected by Advanced LIGO and Advanced Virgo in the first half of the third observing run (O3a) between 1 April 2019 15:00 UTC and 1 October 2019 15:00 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 gamma-ray coordinates network 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 approximately 0.8, as well as events whose components cannot be unambiguously identified as black holes or neutron stars. 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 event masses which are unambiguously identified as binary black holes (both objects ≥3 Mo˙) is increased compared to GWTC-1, with total masses from approximately 14 Mo˙ for GW190924_021846 to approximately 150 Mo˙ for GW190521. For the first time, this catalog includes binary systems with significantly asymmetric mass ratios, which had not been observed in data taken before April 2019. We also find that 11 of the 39 events detected since April 2019 have positive effective inspiral spins under our default prior (at 90% credibility), while none exhibit negative effective inspiral spin. Given the increased sensitivity of Advanced LIGO and Advanced Virgo, the detection of 39 candidate events in approximately 26 weeks of data (approximately 1.5 per week) is consistent with GWTC-1.

Publication Source (Journal or Book title)

Physical Review X

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