The two closest neighbors, both already mentioned, have only recently been discovered: The nearest of all, discovered in 2003, is an already almost
disrupted dwarf galaxy, the Canis Major Dwarf, the nucleus of which is about 25,000 light - years away from us and about 45,000 light - years from the Galactic Center.
The novel Singularity (2012), by Ian Douglas, presents as fact that Omega Centauri and Kapteyn's Star originate from
a disrupted dwarf galaxy, and this origin is central to the novel's plot.