They find a possible satellite galaxy of M33: the largest after Andromeda and the Milky Way

A Spanish research led by the Institute of Astrophysics of Andalusia (IAA-CSIC) has detected a possible satellite galaxy of M33, the third largest of the Local Group after Andromeda and the Milky Way, in a project that discusses its models of formation. The Lambda-Cold Dark Matter cosmological model that explains the origin and evolution of the universe presupposes that observations of some Galaxies in the Local Group, such as neighboring M33, should show numerous satellites even if only one has been detected so far. An investigation led by the Institute of Astrophysics of Andalusia (south) has found a candidate satellite of M33, which could be the starting point for new observations. With between thirty and forty billion stars, the spiral galaxy M33 (or Triangle galaxy) is the third largest of the Local Group, to which the Milky Way belongs and is gravitationally linked to Andromeda, the largest of the group. M33 represents a clear exponent of what is known as the “lost satellites” problem, as simulations estimate that it should have between nine and twenty-five satellite galaxies, but to date only one has been found.” The discovery of a new M33 satellite candidate can change our understanding of the system and the formation of galaxies, and for that reason it is important to carry out a census of dwarf galaxies using the deepest possible data”, explained the researcher Talentia Senior of the IAA-CSIC who leads the work, David Martínez-Delgado.La new galaxy, Called Pisces VII, it was detected by amateur astronomer Giuseppe Donatiello in the public data of the DESI Legacy sampling and, to confirm it, the scientific team used deeper data obtained with a 3.5-meter telescope, which allowed to measure its distance and its absolute magnitude. Analyses have suggested that it could be a satellite of M33, but the distance estimate is very complex and there is another possibility since, if it were farther away, it could be the most isolated dwarf galaxy detected so far.” We plan to confirm whether the motion of this new galaxy is consistent with that of a dwarf galaxy in the Local Group, for which we need spectroscopic observations with an eight- or ten-meter telescope, such as the Large Telescope of the Spanish archipelago of the Canary Islands or the Keck,” added University of Surrey researcher involved in the finding Michelle Collins.

Original source in Spanish