The Local Group is a collection of about forty galaxies, the Milky Way and Andromeda are gravitationally dominant members, with mostly small satellite “dwarf galaxies” bound to these two.
According to the Space report, “The new Local Group members are even smaller and fainter than other known dwarf galaxies, with luminosities ranging from only a thousand to at most a few hundred thousand times that of our Sun.”
They were detected over the last two years by the Sloan Digital Sky Survey.