We report the discovery of a new dwarf galaxy, Andromeda XXVIII, using data from the recently-released SDSS DR8. The galaxy is a likely satellite of Andromeda, and, at a separation of $365^{ +17}_{ -1}$ kpc, would be one of the most distant of Andromeda's satellites. Its heliocentric distance is $650^{ +150}_{ -80}$ kpc, and analysis of its structure and luminosity show that it has an absolute magnitude of $M_V = -8.5^{ +0.4}_{ -1.0}$ and half-light radius of $r_h = 210^{ +60}_{ -50}$ pc, similar to many other faint Local Group dwarfs. With presently-available imaging we are unable to determine if there is ongoing or recent star formation, which prevents us from classifying it as a dwarf spheroidal or dwarf irregular.
Categories: astro-ph.GA