GW170104: observation of a 50-solar-mass binary black hole coalescence at redshift 0.2

LIGO Scientific Collaboration, Virgo Collaboration, A. P. Lundgren

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We describe the observation of GW170104, a gravitational-wave signal produced by the coalescence of a pair of stellar-mass black holes. The signal was measured on January 4, 2017 at 10∶11:58.6 UTC by the twin advanced detectors of the Laser Interferometer Gravitational-Wave Observatory during their second observing run, with a network signal-to-noise ratio of 13 and a false alarm rate less than 1 in 70 000 years. The inferred component black hole masses are 31.2 + 8.4− 6.0 M⊙ and 19.4+5.3− 5.9 M⊙ (at the 90% credible level). The black hole spins are best constrained through measurement of the effective inspiral spin parameter, a mass-weighted combination of the spin components perpendicular to the orbital plane, χ eff =− 0.12+.21− 0.30. This result implies that spin configurations with both component spins positively aligned with the orbital angular momentum are disfavored. The source luminosity distance is 88 0+ 450−390 Mpc corresponding to a redshift of z=0.18+0.08− 0.07. We constrain the magnitude of modifications to the gravitational-wave dispersion relation and perform null tests of general relativity. Assuming that gravitons are dispersed in vacuum like massive particles, we bound the graviton mass to
mg≤7.7×10−23 eV/c2. In all cases, we find that GW170104 is consistent with general relativity.
Original languageEnglish
Article number221101
JournalPhysical Review Letters
Issue number22
Publication statusPublished - 1 Jun 2017


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