Credit: Richard Powell, Source: http://www.atlasoftheuniverse.com.
Published under the terms of the Creative Commons Attribution-ShareAlike 2.5 License.
The Local Group is the group of galaxies that includes our galaxy, the Milky Way. The group comprises over 35 galaxies, with its gravitational center located somewhere between the Milky Way and the Andromeda Galaxy. The galaxies of the Local Group cover a 10 million light-year diameter and have a binary (dumbbell) shape. The group is estimated to have a total mass of (1.29 ± 0.14) X 1012 solar masses. The group itself is one of many within the Virgo Supercluster (i.e. the Local Supercluster).
The two most massive members of the group are the Milky Way and the Andromeda Galaxy. These two barred spirals each have a system of satellite galaxies.
- The Milky Way’s satellite system consists of Sagittarius Dwarf Galaxy, Ursa Major II, Large Magellanic Cloud, Small Magellanic Cloud, Boötes Dwarf, Ursa Minor Dwarf, Sculptor Dwarf, Draco Dwarf, Sextans Dwarf, Ursa Major I, Carina Dwarf, Fornax Dwarf.
- Andromeda’s satellite system comprises M32, M110, NGC 147, NGC 185, And I, And II, And III, And IV, And V, Pegasus dSph, Cassiopeia Dwarf, And VIII, And IX, and And X.
The Triangulum Galaxy, the third largest and only ordinary spiral galaxy in the Local Group, may or may not be a companion to the Andromeda galaxy but probably has Pisces Dwarf as a satellite. The other members of the group are gravitationally secluded from these large subgroups.
The Andromeda Galaxy.