Observation of Gravitational Waves from a Binary Black Hole Merger

B. P. Abbott et al. (LIGO Scientific Collaboration and Virgo Collaboration)

(Received 21 January 2016; published 11 February 2016)

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 ${\displaystyle 1.0\cdot 10^{-21}}$. 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 ${\displaystyle 5.1\sigma }$. The source lies at a luminosity distance of ${\displaystyle 410_{-180}^{+160}}$ Mpc corresponding to a redshift ${\displaystyle z=0.09_{-0.04}^{+0.03}}$. In the source frame, the initial black hole masses are ${\displaystyle 36_{-4}^{+5}{M}_{\odot }}$ and ${\displaystyle 29_{-4}^{+4}{M}_{\odot }}$, and the final black hole mass is ${\displaystyle 62_{-4}^{+4}{M}_{\odot }}$, with ${\displaystyle 3.0_{-0.5}^{+0.5}{M}_{\odot }{c}^2}$ 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.