2011ApJ...742L..14S

We report the discovery of a new dwarf galaxy, Andromeda XXVIII, using data from the recently released Sloan Digital Sky Survey Data Release 8. 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 shows 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 whether there is ongoing or recent star formation, which prevents us from classifying it as a dwarf spheroidal or a dwarf irregular.