Half of Andromeda's dwarf satellite galaxies orbit in a disk planethat is aligned with Milky Way!

Half of Andromeda’s satellite galaxies orbit in a mysterious disk | Ars
Technica
http://arstechnica.com/science/2013/...sterious-disk/

"Large galaxies such as the Milky Way have many smaller satellite
galaxies, bound to them by gravitation. According to the widely accepted
theories of galaxy formation, these satellites were leftovers from the
slow merger process that made the larger galaxies. We'd expected these
satellite galaxies to be evenly distributed around the Milky way, but
recent studies showed that many of them lie close to a single plane,
tilted with respect to the Milky Way's disk. New observations may have
revealed a similar structure of satellites around our closest large
neighbor M31, also known as the Andromeda Galaxy."