The first binary black-hole merger observed by LIGO
In 2015 scientists have observed for the first time gravitational waves, arriving at the earth from a cataclysmic event in the distant universe. The gravitational waves were detected on September 14, 2015 at 5:51 a.m. Eastern Daylight Time (9:51 a.m. UTC) by both of the twin Laser Interferometer Gravitational-wave Observatory (LIGO) detectors, located in Livingston, Louisiana, and Hanford, Washington, USA. The signal was observed for about 0.2 seconds during which it increased both in frequency and amplitude. Its frequency lay between 35 Hz and 250 Hz and it had a peak amplitude (gravitational-wave strain) of 10-21.
The signal matches the predictions of general relativity for those of an inspiral and merger of two black holes with masses of 36 and 29 solar masses, respectively. The black hole resulting from the merger has mass of about 62 solar masses. About 3 times the mass of the sun was converted into gravitational waves in a fraction of a second—with a peak power output about 50 times that of the whole visible Universe. From the observations a distance of about 410 Megaparsecs (1.3 billion light years) to the black hole system was inferred.
The numerical-relativity simulations below show inspiral und merger of the binary black hole system as observed by LIGO.
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