An extraordinary shot, the first real image of the black hole at the center of the galaxy. An exceptional scientific discovery that bears the signature of Sardinia .
The photograph, presented today worldwide, was created thanks to an international collaboration Event Horizon Telescope (Eht) and with the Italian contribution of the National Institute of Astrophysics ( Inaf ), of the National Institute of Nuclear Physics (Infn), of the Federico II University of Naples and the University of Cagliari .
The image is definitive proof that there is a black hole in the center of the Milky Way . Published in 10 articles in The Astrophysical Journal Letters, the result is announced all over the world starting from Germany, with the European Southern Observatory (Eso); in Italy by Inaf, Infn and the two universities.
Three years after the first photo of a black hole, that of the galaxy M87 , the new image definitively confirms the existence of a black hole at the center of our galaxy. An " overwhelming proof ", as the researchers defined it at the press conference organized in Rome. Among the others Ciriaco Goddi of the University of Cagliari, Inaf and Infn , and alongside him Elisabetta Liuzzo Nicola Marchili and Kazi Rygl, all three of INAF and, in connection, Mariafelicia De Laurentis of the Federico II University of Naples and Infn, and Rocco Lico of the Instituto de Astrofísica de Andalucía and Inaf.
Also in this historical shot, the result of the work of more than 300 researchers from 80 institutes around the world that together form the Eht Collaboration, the black hole is not directly visible because it does not emit light: you can see a thick ring of bright gas, some dimensions it would have if it were around the Moon, which surrounds a dark central region called the "shadow".
"Obtaining this image has always been our goal since the beginning of the project and being able to reveal it to the world today repays us for many years of hard work", explains Ciriaco Goddi . "The EHT network is constantly expanding and the subject of major technological updates: so we can have even more impressive images and even films of black holes in the near future."
THE SHOT - The ring is produced by the light distorted by the powerful gravity of the black hole , which has a mass equal to four million times that of the Sun and is 27,000 light years away from Earth, in the direction of the constellation of Sagittarius.
Although the two black holes look very similar, that of the Milky Way is over a thousand times smaller and less massive than that of M87.
The photo was obtained thanks to a global network of eight radio telescopes , including the most powerful in the world: Alma (Atacama Large illimeter / submillimeter Array), in which Italy participates through the European Southern Observatory (Eso) and hosts the Italian node of the Alma European Regional Center at the INAF headquarters in Bologna.
THE RADIOTELESCOPES - The radio telescopes work in unison, as if they were an instrument the size of the Earth and together they were pointed towards the heart of the galaxy for several nights in April 2017 , collecting data for many hours in a row, similar to when you take a long exposure with a camera. Although Sagiuttarius A * is much closer than the first black hole immortalized in a photo, obtaining an image of it was much more difficult: since it is smaller, the gas rotates around it very quickly, taking a few minutes to complete an orbit around the black hole (versus the days taken by the gas around the black hole of M87). Consequently, to obtain the image it was necessary to make an average of the numerous images obtained in the search campaign.
(Unioneonline / vl)