Observation of gravitational waves from a binary black hole merger

On September 14, 2015 at 09:50:45 UTC the two detectors of the Laser Interferometer Gravitational-Wave Observatory simultaneously observed a transient gravitational-wave signal. The signal sweeps upwards in frequency from 35 to 250 Hz with a peak gravitational-wave strain of 1.0 × 10−21. It matches the waveform predicted by general relativity for the inspiral and merger of a pair of black holes and the ringdown of the resulting single black hole. The signal was observed with a matched-filter signal-to-noise ratio of 24 and a false alarm rate estimated to be less than 1 event per 203 000 years, equivalent to a significance greater than5.1σ.Thesourceliesataluminositydistanceof410þ160 Mpccorrespondingtoaredshiftz1⁄40.09þ0.03. −180 −0.04 In the source frame, the initial black hole masses are 36þ5M and 29þ4M , and the final black hole mass is −4⊙ −4⊙ 62þ4M , with 3.0þ0.5M c2 radiated in gravitational waves. All uncertainties define 90% credible intervals. −4 ⊙ −0.5 ⊙ These observations demonstrate the existence of binary stellar-mass black hole systems. This is the first direct detection of gravitational waves and the first observation of a binary black hole merger.