Properties and Astrophysical Implications of the 150 M Binary Black Hole Merger GW190521


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 di Salerno
K. Ackley, Monash 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, Friedrich Schiller Universität Jena
K. Agatsuma, University of Birmingham
N. Aggarwal, Northwestern University
O. D. Aguiar, Instituto Nacional de Pesquisas Espaciais
A. Aich, University of Texas Rio Grande Valley
L. Aiello, Gran Sasso Science Institute
A. Ain, Inter-University Centre for Astronomy and Astrophysics India
P. Ajith, Tata Institute of Fundamental Research, Mumbai
S. Akcay, Friedrich Schiller Universität Jena
G. Allen, University of Illinois at Urbana-Champaign
A. Allocca, Istituto Nazionale di Fisica Nucleare, Sezione di Pisa
P. A. Altin, The Australian National University
A. Amato, Université de Lyon
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
S. Antier, APC - AstroParticule et Cosmologie
S. Appert, California Institute of Technology
K. Arai, California Institute of Technology
Tiffany Z. Summerscales, Andrews UniversityFollow

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© 2020. The American Astronomical Society. All rights reserved. The gravitational-wave signal GW190521 is consistent with a binary black hole (BBH) merger source at redshift 0.8 with unusually high component masses, 85-14+21 M o˙ and 66-18+17 M o˙, compared to previously reported events, and shows mild evidence for spin-induced orbital precession. The primary falls in the mass gap predicted by (pulsational) pair-instability supernova theory, in the approximate range 65-120 M o˙. The probability that at least one of the black holes in GW190521 is in that range is 99.0%. The final mass of the merger (142-16+28 M o˙) classifies it as an intermediate-mass black hole. Under the assumption of a quasi-circular BBH coalescence, we detail the physical properties of GW190521's source binary and its post-merger remnant, including component masses and spin vectors. Three different waveform models, as well as direct comparison to numerical solutions of general relativity, yield consistent estimates of these properties. Tests of strong-field general relativity targeting the merger-ringdown stages of the coalescence indicate consistency of the observed signal with theoretical predictions. We estimate the merger rate of similar systems to be 0.13-0.11+0.30 Gpc-3 yr-1. We discuss the astrophysical implications of GW190521 for stellar collapse and for the possible formation of black holes in the pair-instability mass gap through various channels: via (multiple) stellar coalescences, or via hierarchical mergers of lower-mass black holes in star clusters or in active galactic nuclei. We find it to be unlikely that GW190521 is a strongly lensed signal of a lower-mass black hole binary merger. We also discuss more exotic possible sources for GW190521, including a highly eccentric black hole binary, or a primordial black hole binary.

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Astrophysical Journal Letters







First Department