GW190521: A Binary Black Hole Merger with a Total Mass of 150 𝑀⊙

On May 21, 2019 at 03:02:29 UTC Advanced LIGO and Advanced Virgo observed a short duration gravitational-wave signal, GW190521, with a three-detector network signal-to-noise ratio of 14.7, and an estimated false-alarm rate of 1 in 4900 yr using a search sensitive to generic transients. If GW190521 is from a quasicircular binary inspiral, then the detected signal is consistent with the merger of two black holes with masses of 8⁢5+21 −14  𝑀⊙ and 6⁢6+17 −18  𝑀⊙ (90% credible intervals). We infer that the primary black hole mass lies within the gap produced by (pulsational) pair-instability supernova processes, with only a 0.32% probability of being below 65  𝑀⊙. We calculate the mass of the remnant to be 14⁢2+28 −16  𝑀⊙, which can be considered an intermediate mass black hole (IMBH). The luminosity distance of the source is 5.3+2.4 −2.6  Gpc, corresponding to a redshift of 0.82+0.28 −0.34. The inferred rate of mergers similar to GW190521 is 0.13+0.30 −0.11  Gpc−3 yr−1.