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

Abstract

The gravitational-wave signal GW190521 is consistent with a binary black hole (BBH) merger source at redshift 0.8 with unusually high component masses, M e and M e , compared to previously reported

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

“…For the NRSur7dq4 and IMRPhenomPHM runs, we made use of the LALINFERENCE software package [49] while the SEOBNRv4PHM runs were done using the RIFT algorithm [86]. We find that despite differences in how these waveform models are computed, and the fact that we needed to sample over parameters outside their calibration regions [87], all yield broadly consistent results [39]. In addition, direct comparison of the data to numerical relativity simulations [88][89][90], using the RIFT algorithm, yields consistent results.…”

“…However, for any transient with high inferred masses, there are few cycles observable in ground-based detectors, and therefore alternative signal models may also fit the data. This is further addressed in the companion paper [39] that also provides details about physical parameter estimation, and the astrophysical implications of the observation of GWs from this massive system.…”

“…Despite the short time separation, the inferred sky positions of GW190521 and S190521r are disjointed at high confidence, and so the events are not related by gravitational lensing. Further discussions pertaining to gravitational lensing and GW190521 are presented in the companion paper [39].…”

“…Hence, its astrophysical interpretation as a quasicircular compact binary merger warrants more discussion than previous events. Alternative scenarios, such as an eccentric collision [82], become more relevant and are discussed in the companion paper [39]. Nevertheless, the quasicircular BH merger scenario remains the most plausible and we will proceed under this assumption in the rest of this Letter.…”

“…The NRSur7dq4 results are summarized in Table I. Results for all three models are presented in the companion paper [39]. Figure 2 shows our estimated 90% credible regions for the individual masses of GW190521.…”