It “weighs eleven solar masses, and is located in a stars cluster about 160,000 light-up of the Milky Way.
Le Monde with AFP
Astronomers have detected for the first time a black hole in a very young cluster of stars outside our galaxy, thanks to a method promising new discoveries of these difficult objects to Cerner, reveals a study, Thursday 11 November .
“There are so many black holes in the universe, but we do not know them because we can not see them,” said Sara Saracino, astrophysicist at the Institute of Research in Astrophysics of the University from Liverpool, the United Kingdom. The black color that they are attributed to them only translates the fact that these stars are, by definition, invisible. Their gravitational strength is so powerful that even the light can escape.
It can be detected indirectly, by the radiation emitted at their boundary when they absorb from the material, or by the gravitational waves which causes for example the fusion of two black holes. And if not more directly, when the proximity of the black hole with a near star disrupts the orbit of the latter.
“Small” black hole of eleven solar masses
Thanks to this latter technique, the team led by M me Saracino discovered a black hole of a mass of about eleven sun, located in the nGC 1850 stars cluster of the Grand cloud of Magellan, a galaxy close to the Milky Way, about 160,000 light years. This “small” black hole distorts a little close star, which weighs five solar masses. “This is the first time one detects one with this technique in a very young cluster”, apart from our milky way, says the scientist, whose study seems in the Monthly notices of the Royal Astronomical Society.
To find it, scientists have used Muse, a broad field spectrograph, installed in just a few years on the very large telescope of the European Austral European Observatory (ESO) in Chile. It has made it possible to “observe a populated area”, according to Sebastian Kammann, co-author of the study, cited in an ESO statement, “with information on thousands of stars at once, ten times more than with any other instrument “.
The relative youth of the cluster – less than 100 million years – is an asset, because “there is a kind of black holes very different, in the sense they have been trained very recently,” explains Still Sara Saracino. They did not have time to be expelled, “as is the case with the very old stars climb”, or especially to interact with each other.
The fact that it is young and still “lightweight” interests all the more scientists, who seek to characterize the whole range of black holes. Of those with “stellar”, like the one identified by the Sara Sara team, to the supermassants reaching several millions of solar masses, through the “intermediaries”, whose very existence remains played.