An international team of astronomers has confirmed the discovery of a spheroidal dwarf galaxy at the far end of the galaxy of Andromeda, according to the Institute of Astrophysics of the Canary Islands (IAC).
The finding was made in the first instance by the amateur astrophotographer Giuseppe Donatiello, who found it while analyzing diverse images of Andromeda that had captured between the years 2010 and 2013 from the National Park of Pollino, in the south of Italy. The new galaxy is called 'Donatiello I' in his honor.
Observations made with the Gran Telescopio Canarias (GTC) and the Galileo National Telescope (TNG) have revealed that this set of stars is 9.78 million light years.
Based on the position and distance of 'Donatiello I', the researchers handle the hypothesis that it is a dwarf satellite of the elliptical galaxy called 'The Phantom of Mirach', due to its proximity to the star Mirach (the second brightest of the Andromeda constellation).
According to the data analyzed so far, the newly discovered dwarf galaxy is composed mainly of old stars, and its content resembles that of other galaxies relatively close to the Milky Way, such as the Draco Dwarf Galaxy or the Lesser Bear.
In the article that reports the discovery and characteristics of 'Donatiello I', the researcher of the IAC Mike Beasley "The absence of young stars and lack of gas are typical of spheroidal dwarf galaxies that stopped forming stars several billion years ago."
On the other hand, David Martínez Delgado, A researcher at the University of Heidelberg (Germany) and lead author of the article, argues that "it is of great interest for the theory of galaxy formation to carry out a complete inventory of dwarf galaxies in the vicinity of the Local Group ".
The so-called Local Group consists of about 30 small galaxies plus three large spiral galaxies: Andromeda, the Triangle galaxy, and the Milky Way, in which our Solar System is located.
Martínez Delgado comments on the discovery of Donatiello I, noting that "ultra deep images of large areas of the sky taken with small telescopes by amateur astrophotographers can help complete the census of these low surface gloss galaxies", which specifies that" can not currently be detected with the mapping based on the counting of individual stars or the detection of the emission of the neutral hydrogen gas. "