First detection of gravitational waves involving scientists of the Physics Division

The scientists of the UNICAM Physics Division members of the VIRGO experiment of the Italian Institute of Nuclear Physics (INFN), and the various UNICAM students which has participated to that are proud to annouce this historical event, which has occured just 100 years after the publication of the theory of General Relativity by Einstein, who predicted the existence of gravitational waves. 

On September 14, 2015 at 09:50:45 UTC the two detectors of the Laser Interferometer Gravitational-wave Observatory (LIGO) simultaneously observed a transient gravitational-wave signal.

The signal sweeps upwards in frequency from 35 Hz 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 ring-down 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 202,600 years, equivalent to a significance greater than 5.1s. The source lies at a luminosity distance of 410+160-180 Mpc corresponding to a redshift z = 0.09+0.03-0.04. In the source frame, the initial black hole masses are 36+5-4 M⃝ and 29+4-4 M⃝, and the final black hole mass is 62+4-4 M⃝, with 3.0+0.5-0.5 M⃝c2 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.

For more info click on the links below

LIGO web-site

VIRGO web-site

Phys. Rev. Lett.