The Sloan Digital Sky Survey has just released details of the discovery of a "new" dwarf galaxy, found toward the constellation Virgo.
http://www.sdss.org/news/releases/20...erdensity.html
Their researchers believe it is a dwarf galaxy that is merging into the Milky Way. It's a huge faint structure covering an area more than 5000 times the size of a full moon, and some of the stars in it have been observed in telescopes for years, but have only been identified as part of this structure as a result of this survey.