Gravitational observatories LIGO and VIRGO for the first time simultaneously detected a surge of gravitational waves generated by the fusion of two black holes and localized their source - one of the galaxies in the constellation of Hours.

"Combining the efforts of LIGO and VIRGO not only increased the accuracy of the localization of sources of gravitational waves by a factor of 20, but also enabled us to proceed to search for traces of objects generating gravitational waves in other types of radiation. Today we have really entered the era of full-fledged gravitational astronomy, "said David Shoemaker, head of the LIGO collaboration at the meeting in Turin.

The LIGO detectors are L-shaped interferometers that, due to laser beams, follow with an incredible accuracy the length of both their 4-kilometer "arms": a passing gravitational wave can cause brief distortions, which is recorded by instruments.

The efforts of scientists have justified themselves - in September 2015, virtually immediately after the inclusion of the updated LIGO, scientists discovered a surge of gravitational waves generated by merging black holes with a total mass of 53 Suns. Subsequently, LIGO recorded three more bursts of gravitational waves, however, only one of which was officially recognized by the scientific community.

Scientists could not determine exactly where the sources of these gravitational waves were located, since LIGO has only two detectors. The researchers then only managed to allocate a fairly narrow band in the night sky, where these black holes could be located. Inside it, despite its modest size, there are millions of galaxies, which makes the search for the "final product" of these mergers a virtually useless occupation.

In June 2017, the European LIGO, the gravitational observatory VIRGO, built in the vicinity of the Italian Pisa in 2003, resumed its work.. The work of VIRGO was suspended in 2011, after which the engineering team of the observatory carried out its deep modernization, bringing it closer to sensitivity to the current level of LIGO.

One of the features of the European detector, as Jo van den Brand, the head of the VIRGO collaboration, added, is that he will turn slightly in the opposite direction compared to a pair of his American "brethren". This allows scientists to use them to measure the polarization of gravitational waves and to test some of the main provisions of the theory of relativity, as well as to search for parallel worlds.

All inspections of the VIRGO detectors were completed by August 1, 2017, and the observatory now began joint observations with two LIGO detectors. Its sensitivity is somewhat lower than that of the American gravitational telescope, but the data obtained by it can solve two of the most important scientific problems: to improve the quality and reliability of the signal obtained by LIGO and to determine the three-dimensional position of the source of gravitational waves.

The first results were achieved unexpectedly quickly - on August 14 they were able to detect a burst of GW170814, which originated in the distant galaxy at a distance of 1.8 billion. light years from the Earth. As in the previous three cases, these waves were generated by unusually large black holes, whose mass exceeded the solar one by 30.5 and 25 times. During their confluence, approximately three solar masses "evaporated" and were spent on the radiation of gravitational waves.

The use of three detectors by scientists made it possible to significantly improve the accuracy of the localization of the source of gravitational waves - the galaxy in which the black holes that spawned them are located in a small area of ??the sky in the constellation of the Clock in the night sky of the southern hemisphere of the Earth. In addition, scientists plan to use this data to search for possible traces of this outbreak in the radio and X-ray ranges.

Sensations in this case did not happen - a preliminary analysis of the data collected by LIGO and VIRGO during this outbreak shows that gravitational waves move through space and behave exactly as predicted by Einstein's theory. In the future, when the sensitivity of LIGO and VIRGO will be increased, scientists hope to find the final answer to this question. This is reported on the site Science Alert.