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 365−1+17 kpc, would be one of the most distant of Andromeda's satellites. Its heliocentric distance is 650−80+150 kpc, and analysis of its structure and luminosity show that it has an absolute magnitude of MV=−8.5−1.0+0.4 and half-light radius of rh=210−50+60 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.
@article{arxiv.1110.5903,
title = {Andromeda XXVIII: A Dwarf Galaxy More Than 350 kpc from Andromeda},
author = {Colin T. Slater and Eric F. Bell and Nicolas F. Martin},
journal= {arXiv preprint arXiv:1110.5903},
year = {2015}
}