The Rate of Binary Black Hole Mergers Inferred From Advanced Ligo Observations Surrounding Gw150914

Abstract

A transient gravitational-wave signal, GW150914, was identified in the twin Advanced LIGO detectors on 2015 September 2015 at 09:50:45 UTC. To assess the implications of this discovery, the detectors remained in operation with unchanged configurations over a period of 39 days around the time of the signal. At the detection statistic threshold corresponding to that observed for GW150914, our search of the 16 days of simultaneous two-detector observational data is estimated to have a false-alarm rate (FAR) of <´--4.9 10 yr

Production of high stellar-mass primordial black holes in trapped inflation

“…The discovery opens up a new era of gravity-wave astronomy and cosmology. The detected gravity-wave source GW150914 provides an evidence for the existence of high stellar-mass binary black-hole (BBH) systems with masses 29M ⊙ and 36M ⊙ that inspiral and merge within the age of the Universe, with an inferred merger rate of 2 − 400Gpc −3 yr −1 [2]. So far, neither electromagnetic nor neutrino counterparts have been confirmed, implying that gas accretion onto the BH binary is insignificant at the time of merging.…”

GW150914: Implications for the Stochastic Gravitational-Wave Background from Binary Black Holes

“…In addition, the coalescence rate of binary black holes like GW150914 in the local Universe is estimated to be 16 þ38 −13 Gpc −3 yr −1 (Table I [ 16]) median with a 90% credible interval. This rate excludes the lower end of predetection rate estimates [15], while being consistent with the higher end.…”

“…The deltafunction mass distributions assumed in all models are motivated by the observed candidates, but are not realistic. We have analyzed two alternative broad mass distributions considered in [16], flat in the log-mass of the component black holes and a Salpeter-like mass function for the larger black hole with a flat mass ratio; these yield broadly consistent energy densities. We have not carried out a systematic study of black hole spin.…”

“…(vi) LowMass is the same as the Fiducial model except we add a second class of lower-mass binary black hole sources corresponding to a smaller range for individual detections during O1. As an example, we assume a chirp mass of half the mass of GW150914, M c ¼ 15M ⊙ and a local merger rate of 61 Gpc −3 yr −1 [5,16], corresponding to the second most significant event (LVT151012) identified in [4,39] with insufficient significance to decisively claim a detection. Here, we assume that the metallicity threshold is Z c ¼ Z ⊙ .…”

“…We normalize the overall merger rate so that the local merger rate at z ¼ 0 matches the most conservative median inferred rate, 16 Gpc −3 yr −1 [16].…”