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First cosmic event observed in both gravitational waves and light



Credit: ESO/L. Calįada/M. Kornmesser

Astronomers from different collaborations announced on Monday 16 October the detection of two colliding neutron stars by the gravitational-wave observatories LIGO and VIRGO and also by 70 other, more traditional, electromagnetic-wave observatories. This is the first time scientists have detected gravitational waves in addition to light from the same cosmic event, opening a new window in observational astronomy, the ‘multi-messenger’ astronomy.

After the signal being detected by the two LIGO detectors in USA and VIRGO in Italy, the position of the event could be precisely triangulated and scientists could locate it in a relatively small patch in the southern sky. Fermi Observatory was able to provide a localization that was later confirmed and greatly refined with the coordinates provided by the LIGO-Virgo detection. With these coordinates some 70 ground- and space-based observatories could point their telescopes to the event and perform follow-up observations in all the range of the electromagnetic spectrum.

The observed event was the merging of two neutron stars located at the relatively close distance of about 130 million light-years from Earth. As these neutron stars spiraled together, they emitted gravitational waves that were detectable for about 100 seconds; when they collided, a flash of light in the form of gamma rays was emitted and seen on Earth about 2 seconds after the gravitational waves. In the days and weeks following the smashup, other forms of or electromagnetic radiation -- including X-ray, ultraviolet, optical, infrared and radio waves -- were detected.


NSF press release


Interview to R. Emparan on Catalunya Rādio

New details and discoveries made in the ongoing search for gravitational waves Online retransmission of NSF press conference

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