A group of researchers from the National Institute of Astrophysics (INAF) has discovered that the Shapley supercluster, a giant made up of a thousand galaxies, located between 500 and 700 million light years from Earth, has been hit and crossed like a bullet from another cluster, smaller in proportion, but still colossal, made up of another hundred galaxies; the cosmic “bullet” dragged behind a trail of excited matter, several million light years long, very difficult to see with optical telescopes but possible to detect at radio frequencies and X-rays. In this regard, the INAF group coordinated an international research which was also attended by a South African and an Indian radio telescope, as well as ESO’s Vlt Survey Telescope and ESA’s XMM-Newton space telescope. The results will appear in an article in the journal Astronomy & Astrophysics.
Superclusters of galaxies are the largest objects in the Universe. What we are now talking about, discovered and studied by the astronomer Harlow Shapley between the 1920s and 1940s, is particularly turbulent: it hosts several mega-collisions between clusters and is invaluable as a laboratory for the analysis of large structures in which articulates the Cosmos.
Says Tiziana Venturi, director of the INAF Radio Astronomy Institute in Bologna, first author of the article on Astronomy & Astrophysics: «This emission is exceptional also because it finally allows us to study the regions of cosmic space located between clusters of galaxies»; it is precisely there that the gravitational bridge of excited matter extends. The astronomer Venturi also points out that the research has made it possible to identify two previously unknown galaxies of unusual nature, whose characteristics were influenced precisely by the collision between clusters. These discoveries will have to be studied for years.