The black hole at the center of our galaxy, the Milky Way, has been photographed, and the closest one, thanks to international collaboration Event Horizon Telescope (Eht) and with the Italian contribution of National Institute of Astrophysics (Inaf), National Institute of Nuclear Physics (Infn), Federico II University of Naples and Cagliari.
The image is definitive proof that there is a black hole at the center of the Milky Way. Published in 10 articles on 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 M87 galaxy, the new image definitively confirms the existence of a black hole at the center of our galaxy: “overwhelming proof”, as the researchers defined it in the press conference organized in Rome: Ciriaco Goddi of the University of Cagliari, Inaf and Infn, Elisabetta Liuzzo Nicola Marchili and Kazi Rygl, all three from INAF and, in connection, Mariafelicia De Laurentiis of the Federico II University of Naples and Infn, and Rocco Lico of the Institute of Astrophysics of Andalusia and Inaf.
Even in this historic shot, the result of work of more than 300 researchers from 80 institutes worldwide which together form the EHT Collaboration, the black hole is not directly visible because it does not emit light: we see a thick ring of bright gas, about the size it would be if it were around the Moon, surrounding a dark central region called the 'shadow'.
The ring is produced by light distorted by the powerful gravity of the black hole, which has a mass four million times that of the Sunglasses ed It is 27.000 light years away from Earth., in the direction of the Sagittarius constellation. Although the two black holes appear very similar, the Milky Way's is over a thousand times smaller and less massive than the one in M87.
The photo was obtained through a global network of eight radio telescopes, including the most powerful in the world: the soul (Atacama Large illimeter/submillimeter Array), to which theItaly participates through the European Southern Observatory (ESO) and hosts the Italian node of the Alma European Regional Centre at the Inaf headquarters in Bologna.
The radio telescopes work in unison, as if they were one Earth-sized instrument, and together they were pointed at the heart of the galaxy for several nights in April 2017, collecting data for many hours at a time, similar to taking a long exposure with a camera.
Although Sagiuttarius A* is much closer than the first black hole ever photographed, obtaining an image of it was much more difficult: because it is smaller, the gas around it rotates very quickly, taking only minutes to complete an orbit around the black hole (compared to the days taken by the gas around the black hole in M87). Consequently, obtaining the image required averaging the many images obtained in the search campaign.
Article published on May 12, 2022 - 15:21 pm
