Local Group

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The Local Group (also called M31 group or the Andromeda group) is the group of galaxies that includes our galaxy, the Milky Way. The group comprises over 30 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 (see 1 E23 m for distance comparisons). The group belongs to the Virgo Supercluster.

The two most massive members of the group are the Milky Way and the Andromeda Galaxy. These two spirals each have a system of satellite galaxies. The Milky Way's satellite system consists of Sag DEG, Large Magellanic Cloud, Small Magellanic Cloud, Canis Major Dwarf, Ursa Minor Dwarf, Draco Dwarf, Carina Dwarf, Sextans Dwarf, Sculptor Dwarf, Fornax Dwarf, Leo I, Leo II and Tucana Dwarf. Andromeda's 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. M33, the third largest galaxy in the Local Group, may or may not be a companion to the Andromeda galaxy but probably has LGS 3 as a satellite. The other members of the group are gravitationally secluded from these large subgroups.

Image:Local.group.arp.600pix.jpg

• Spiral galaxies
  • Milky Way - type SBbc
  • Andromeda Galaxy (M31, NGC 224) - type SAb in Andromeda
  • Triangulum Galaxy (M33, NGC 598) - type SAc in Triangulum

• Elliptical galaxies
  • M110 (NGC 205) - type E6p in Andromeda
  • M32 (NGC 221) - type E2 in Andromeda

• Irregular galaxies
  • Wolf-Lundmark-Melotte (WLM, DDO 221) - type Ir+ in Cetus
  • IC 10 - type KBm or Ir+ in Cassiopeia
  • Small Magellanic Cloud (SMC, NGC 292) - SB(s)m pec in Tucana
  • Canis Major Dwarf - type Irr in Canis Major
  • Pisces Dwarf (LGS3) - type Irr in Pisces
  • IC 1613 (DDO 8) - type IAB(s)m V in Cetus
  • Phoenix Dwarf - type Irr in Phoenix
  • Large Magellanic Cloud (LMC) - type Irr/SB(s)m in Dorado
  • Leo A (Leo III) - type IBm V in Leo
  • Sextans B (DDO 70) - type Ir+IV-V in Sextans
  • NGC 3109 - type Ir+IV-V in Hydra
  • Sextans A (DDO 75) - type Ir+V in Sextans

• Dwarf elliptical galaxies
  • NGC 147 (DDO 3) - type dE5 pec in Cassiopeia
  • GR 8 (DDO 155) - type Im V
  • SagDIG (Sagittarius Dwarf Irregular Galaxy) - type IB(s)m V in Sagittarius
  • NGC 6822 (Barnards Galaxy) - type IB(s)m IV-V in Sagittarius
  • Aquarius Dwarf (DDO 210) - type Im V in Aquarius
  • IC 5152 - type IAB(s)m IV in Indus
  • Pegasus Dwarf or Pegasus Dwarf Irregular (DDO 216) - type Irr in Pegasus

• Dwarf spheroidal galaxies
  • Cetus Dwarf - type dSph/E4 in Cetus
  • Andromeda III - type dE2 in Andromeda
  • NGC 185 - (type dE3 pec) - Cassiopeia
  • Andromeda I - type dE3 pec? in Andromeda
  • Sculptor Dwarf (E351-G30) - type dE3 in Sculptor
  • Andromeda V - type dSph in Andromeda
  • Andromeda II - type dE0 in Andromeda
  • Fornax Dwarf (E356-G04) - type dSph/E2 in Fornax
  • Carina Dwarf (E206-G220) - type dE3 in Carina
  • Antlia Dwarf - type dE3 in Antlia
  • Leo I (DDO 74) - type dE3 in Leo
  • Sextans Dwarf - type dE3 in Sextans
  • Leo II (Leo B) - type dE0 pec in Leo
  • Ursa Minor Dwarf - type dE4 in Ursa Minor
  • Draco Dwarf (DDO 208) - type dE0 pec in Draco
  • Sag DEG (Sagittarius Dwarf Elliptical Galaxy) - type dSph/E7 in Sagittarius
  • Tucana Dwarf - type dE5 in Tucana
  • Cassiopeia Dwarf (Andromeda VII) - type dSph in Cassiopeia
  • Pegasus Dwarf Spheroidal Galaxy (Andromeda VI) - type dSph in Pegasus
  • Ursa Major Dwarf - type dSph in Ursa Major

• Identification Unclear
  • Andromeda IV - Irregular Galaxy or Star Cloud (Irr?) in Andromeda
  • UGC-A 86 (0355+66) - Irregular, Elliptical or Lenticular Galaxy (Irr, dE or S0) in Camelopardalis
  • UGC-A 92 (EGB0427+63) - Irregular or Lenticular Galaxy (Irr or S0) in Camelopardalis

• Probable non-members
  • NGC 404 - Elliptical or Lenticular Galaxy (E0 or SA(s)0-) in Andromeda
  • NGC 1569 - Irregular Galaxy (Irp+ III-IV) in Camelopardalis
  • NGC 1560 (IC 2062) - Spiral Galaxy (Sd) in Camelopardalis
  • Camelopardalis A - Irregular Galaxy (Irr) in Camelopardalis
  • Argo Dwarf - Irregular Galaxy (Irr) in Carina
  • 2318-42 - Irregular Galaxy (Irr) in Grus
  • UKS 2323-326 - Irregular Galaxy (Irr) in Sculptor
  • UGC 9128 (DDO 187) - Irregular Galaxy (Irp+) in Boötes
  • Capricornus Dwarf (Palomar 12) is a Milky Way Globular Cluster formerly classified as a Dwarf Spheroidal Galaxy in Capricornus
  • Original Ursa Major Dwarf (Palomar 4) is a Milky Way Globular Cluster formerly classified as a Dwarf Spheroidal Galaxy in Ursa Major
  • Sextans C

See also

• Groups and clusters of galaxies
• List of nearest galaxies

External links

• The Local Group of Galaxies, SEDS Messier pages
• A Survey of the Resolved Stellar Content of Nearby Galaxies Currently Forming Stars, Lowell Observatory

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