[gary]

Originally Posted by Adrian Cho, Science, 27 Sept 2017

For a fourth time, physicists have spotted gravitational waves—ripples in space itself—set off by the merger of two massive black holes. But this time, they detected the waves not only with two detectors in the United States, but also with a third detector in Europe: the Virgo detector near Pisa, Italy. The three-way detection enabled researchers to home in on the location of the black holes on the sky with 10 times greater precision than before, and to probe the polarization of gravitational waves in new ways. The result also independently confirms the blockbuster discovery of gravitational waves made 2 years ago.

Originally Posted by Govert Schilling, Sky & Telescope, 27 Sep 2017

According to a Physical Review Letters paper by the LIGO-Virgo Collaboration, the gravitational waves that reached Earth on Monday, August 14th, at 10:30:43 UT were unleashed by the collision of two black holes, weighing in at 31 and 25 solar masses. During the merger event, which took place at a distance of some 1.8 billion light-years, the energy equivalent of 3 solar masses was radiated away in the form of gravitational waves, leaving a 53-solar-mass black hole behind.

https://www.sciencemag.org/news/2017...tational-waves

http://www.skyandtelescope.com/astro...vent-detected/

https://www.theguardian.com/science/...ion-ligo-virgo

https://astronomynow.com/2017/09/27/...igo-and-virgo/