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 1in 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 85⁺²¹₋₁₄ M⊙ and 66⁺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, and has only a 0.32 % probability of being below 65 M⊙. We calculate the mass of the remnant to be 142⁺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⁻³yr⁻¹.