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 10×10 −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 than 51σ The source lies at a luminosity distance of 410 +160 −180   Mpc corresponding to a redshift z=009 +003 −004 In the source frame the initial black hole masses are 36 +5 −4 M ⊙ and 29 +4 −4 M ⊙ and the final black hole mass is 62 +4 −4 M ⊙ with 30 +05 −05 M ⊙ c 2 radiated in gravitational waves All uncertainties define 90% credible intervals 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.