A member of the Local Group of galaxies, irregular galaxy Sextans A is 4. Sextans A ( as known as UGCA 205) is a tiny dwarf irregular Galaxy. 3 million light-years distant. The bright Milky Way foreground stars appear yellowish in this view. Beyond them lie the stars of Sextans A with young blue star clusters clearly visible.

The Local Group is the group of galaxies that includes our galaxy, the Milky Way. Galaxy groups and clusters are the largest Gravitationally bound objects to have arisen thus far in the process of cosmic structure formation A galaxy is a massive gravitationally bound system consisting of Stars an Interstellar medium of gas and dust, and Dark matter The Milky Way (a translation of the Latin Via Lactea, in turn derived from the Greek Γαλαξίας (Galaxias sometimes referred to simply The group comprises over 35 galaxies, with its gravitational center located somewhere between the Milky Way and the Andromeda Galaxy. The Andromeda Galaxy (ænˈdrɒmədə also known as Messier 31, M31, or NGC 224; often referred to as the Great Andromeda The galaxies of the Local Group cover a 10 million light-year diameter (see 1 E+22 m for distance comparisons) and have a binary (dumbbell)^[1] shape. A light-year or light year (symbol ly) is a unit of Length, equal to just under ten trillion Kilometres As defined by The group is estimated to have a total mass of (1. 29 ± 0. 14)×10¹²M_☉. The solar mass is a standard way to express Mass in Astronomy, used to describe the masses of other Stars and galaxies. ^[1] The group itself is one of many within the Virgo Supercluster (i. The Virgo Supercluster or Local Supercluster is the galactic Supercluster that contains the Local Group, the latter containing in its turn e. the Local Supercluster). ^[2]

The two most massive members of the group are the Milky Way and the Andromeda Galaxy. The Milky Way (a translation of the Latin Via Lactea, in turn derived from the Greek Γαλαξίας (Galaxias sometimes referred to simply The Andromeda Galaxy (ænˈdrɒmədə also known as Messier 31, M31, or NGC 224; often referred to as the Great Andromeda These two barred spirals each have a system of satellite galaxies. A barred spiral galaxy is a Spiral galaxy with a central bar-shaped structure composed of Stars Bars are found in approximately half of all spiral galaxies

• The Milky Way's satellite system consists of Sagittarius Dwarf Galaxy, 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 Ursa Major Dwarf. The Milky Way Galaxy has several smaller galaxies gravitationally bound to it as part of the Milky Way subgroup. The Sagittarius Dwarf Elliptical Galaxy ( SagDEG) is an elliptically looped shaped Satellite galaxy of the Milky Way Galaxy. The Large Magellanic Cloud (LMC is a nearby Satellite galaxy of our own galaxy the Milky Way. The Small Magellanic Cloud (SMC is a Dwarf galaxy. It contains several hundred million stars The Canis Major Dwarf galaxy is located in the same part of the sky as the Constellation of Canis Major. The Ursa Minor Dwarf Dwarf elliptical galaxy was discovered by A The Draco Dwarf is a spheroidal galaxy which was discovered by Albert George Wilson of Lowell Observatory in 1954 on photographic plates of the The Carina Dwarf Spheroidal is a Dwarf galaxy in the Carina Constellation. The Sextans Dwarf Spheroidal is a Dwarf spheroidal galaxy that was discovered in 1990 by Mike Irwin M The Sculptor Dwarf Galaxy (also called the Sculptor Dwarf Elliptical Galaxy or the Sculptor Dwarf Spheroidal Galaxy) is a Dwarf spheroidal galaxy that The Fornax Dwarf Spheroidal is an elliptical Dwarf galaxy in the Constellation Fornax that was discovered in 1938 by Harlow Shapley. Leo I is a Dwarf spheroidal galaxy in the Constellation Leo. At about 820000 Light-years distant it is a member of the Local Group Leo B (or Leo II) is an dwarf spheroidal Galaxy of the Local Group, part of the Milky Way subgroup in the Constellation of
• 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 Andromeda Galaxy has satellite galaxies just like the Milky Way Galaxy. Messier 32 (also known as NGC 221 and Le Gentil) is a Dwarf elliptical galaxy about 2 Messier 110 (also known as M110 and NGC 205) is a Dwarf elliptical galaxy that is a satellite of the Andromeda Galaxy. NGC 147 (DDO3 is a Dwarf spheroidal galaxy about 258 Mly away in the Constellation Cassiopeia. NGC 185 is a Dwarf elliptical galaxy about 208 million Light-years away in the Constellation Cassiopeia. Andromeda I is a Dwarf spheroidal galaxy (dSph about 240 As of 2005 it is the closest known dSph companion to M31 at an estimated projected distance of ~40 kpc Andromeda II (And II is a Dwarf spheroidal galaxy about 222 Mly away in the Constellation Andromeda. Andromeda III is a Dwarf spheroidal galaxy about 244 million Light-years away in the Constellation Andromeda. Andromeda IV (And IV might be an irregular satellite of the Andromeda Galaxy, but is probably not a Galaxy at all but just a loose Andromeda V is a Dwarf spheroidal galaxy about 252 Mly away in the Constellation Andromeda. The Pegasus Dwarf Spheroidal (also known as Andromeda VI or Peg dSph for short is a Dwarf spheroidal galaxy about 2 The Cassiopeia Dwarf (also known as Andromeda VII) is a Dwarf spheroidal galaxy about 2 Andromeda VIII (And VIII / 8 is a Galaxy discovered in August 2003. Andromeda IX (And 9 is a dwarf spheroidal satellite of the Andromeda Galaxy, it was discovered in 2004 by resolved stellar photometry from Andromeda X (And 10 is a Dwarf spheroidal galaxy about 29 million Light-years away from the Sun in the Constellation Andromeda
• 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 Triangulum Galaxy (also known as Messier 33 or NGC 598) is a Spiral galaxy approximately 3 million light-years away in the A spiral galaxy is a Galaxy belonging to one of the three main classes of galaxy originally described by Edwin Hubble in his 1936 work “The Realm of the Pisces Dwarf is an irregular dwarf Galaxy that is part of the Local Group.

The other members of the group are gravitationally secluded from these large subgroups: IC1613, Phoenix Dwarf, Leo A, Tucana Dwarf, Cetus Dwarf, Pegasus Dwarf Irregular, WLM, Aquarius Dwarf, and Sagittarius Dwarf Irregular. IC 1613 is an Irregular galaxy and a Dwarf galaxy in the Cetus constellation near 26 Ceti. The Phoenix Dwarf is a Dwarf galaxy and an Irregular galaxy that was discovered in 1976 by Hans-Emil Schuster and Richard Martin West Leo A ( also known as Leo III) is an irregular Galaxy that is part of the Local Group. The Tucana Dwarf Galaxy is a Dwarf galaxy in the Constellation Tucana. Cetus Dwarf is an Dwarf spheroidal galaxy. It lies ~246 Million light-years from Earth The Pegasus Dwarf Irregular Galaxy (also known as Peg DIG or the Pegasus Dwarf) is an Irregular galaxy and a Dwarf galaxy in the direction The Aquarius Dwarf Galaxy is a Dwarf galaxy and an Irregular galaxy, that was first catalogued in 1966 by the DDO survey. The Sagittarius Dwarf Irregular Galaxy or SagDIG is a Dwarf galaxy in the Constellation of Sagittarius.

History

Edwin Hubble was the first to identify the Local Group in Chapter VI of his book The Realm of Nebulae (Hubble 1936, pp. Edwin Powell Hubble ( November 20, 1889 – September 28, 1953) was an American astronomer. 124-151). There he describes it as "a typical small group of nebulae which is isolated in the general field. " In that book, he delineated by decreasing luminosity its members to be M31, the Milky Way, M33, the Large Magellanic Cloud, the Small Magellanic Cloud, M32, NGC 205, NGC 6822, NGC 185, IC 1613 and NGC 147. The Milky Way (a translation of the Latin Via Lactea, in turn derived from the Greek Γαλαξίας (Galaxias sometimes referred to simply The Large Magellanic Cloud (LMC is a nearby Satellite galaxy of our own galaxy the Milky Way. The Small Magellanic Cloud (SMC is a Dwarf galaxy. It contains several hundred million stars Messier 110 (also known as M110 and NGC 205) is a Dwarf elliptical galaxy that is a satellite of the Andromeda Galaxy. NGC 6822 (also known as Barnard's Galaxy or IC 4895) is a Barred irregular galaxy approximately 1 NGC 185 is a Dwarf elliptical galaxy about 208 million Light-years away in the Constellation Cassiopeia. IC 1613 is an Irregular galaxy and a Dwarf galaxy in the Cetus constellation near 26 Ceti. NGC 147 (DDO3 is a Dwarf spheroidal galaxy about 258 Mly away in the Constellation Cassiopeia. He also identified IC 10 as a possible Local Group member. IC 10 is an Irregular galaxy in the Constellation Cassiopeia. In the ~70 years since his work, the number of known Local Group members has increased from his initial 12 to 36 in 2003. This was by way of almost two dozen low-luminosity galaxies. ^[3]

Component galaxies

Map

Map of the Local Group of Galaxies

Galactic bodies

Other notable objects

• Smith's Cloud - High velocity cloud, between 32,000 and 49,000 light years from Earth^[5], and 8000 light years the disk of the Milky Way Galaxy^[6]. NGC 6822 (also known as Barnard's Galaxy or IC 4895) is a Barred irregular galaxy approximately 1 The Pegasus Dwarf Irregular Galaxy (also known as Peg DIG or the Pegasus Dwarf) is an Irregular galaxy and a Dwarf galaxy in the direction The Pegasus Dwarf Irregular Galaxy (also known as Peg DIG or the Pegasus Dwarf) is an Irregular galaxy and a Dwarf galaxy in the direction Pegasus (ˈpɛɡəsəs is a northern Constellation, named after the mythological winged horse Pegasus. Dwarf spheroidal galaxy ( dSph) is a term in Astronomy applied to low luminosity Galaxies that are Companions to the Milky The Boötes Dwarf Galaxy ( Boo dSph) is the faintest galaxy yet discovered as of 2006, with a total luminosity of 100000 Suns and an absolute magnitude Boötes ( Greek Βοώτης or herdsman) is one of the 88 modern Constellations and was also one of the 48 constellations listed by Ptolemy. Cetus Dwarf is an Dwarf spheroidal galaxy. It lies ~246 Million light-years from Earth The Canes Venatici Dwarf ( CVn dSph) is one of the most distant Satellite galaxy of the Milky Way as of 2006 together with Leo I Canes Venatici ( Hunting dogs) is a small northern Constellation that was introduced by Johannes Hevelius in the 17th century Andromeda III is a Dwarf spheroidal galaxy about 244 million Light-years away in the Constellation Andromeda. NGC 185 is a Dwarf elliptical galaxy about 208 million Light-years away in the Constellation Cassiopeia. Andromeda I is a Dwarf spheroidal galaxy (dSph about 240 As of 2005 it is the closest known dSph companion to M31 at an estimated projected distance of ~40 kpc The Sculptor Dwarf Galaxy (also called the Sculptor Dwarf Elliptical Galaxy or the Sculptor Dwarf Spheroidal Galaxy) is a Dwarf spheroidal galaxy that The Sculptor Dwarf Galaxy (also called the Sculptor Dwarf Elliptical Galaxy or the Sculptor Dwarf Spheroidal Galaxy) is a Dwarf spheroidal galaxy that Sculptor (ˈskʌlptɚ is a minor southern Constellation which was introduced by Nicolas Louis de Lacaille. Andromeda V is a Dwarf spheroidal galaxy about 252 Mly away in the Constellation Andromeda. Andromeda II (And II is a Dwarf spheroidal galaxy about 222 Mly away in the Constellation Andromeda. The Fornax Dwarf Spheroidal is an elliptical Dwarf galaxy in the Constellation Fornax that was discovered in 1938 by Harlow Shapley. The Fornax Dwarf Spheroidal is an elliptical Dwarf galaxy in the Constellation Fornax that was discovered in 1938 by Harlow Shapley. Fornax (ˈfɔrnæks Furnace) is a southern Constellation which was first introduced by Nicolas Louis de Lacaille under the name Fornax Chemica The Carina Dwarf Spheroidal is a Dwarf galaxy in the Carina Constellation. The Carina Dwarf Spheroidal is a Dwarf galaxy in the Carina Constellation. Carina ( Keel) is a southern Constellation which forms part of the old constellation of Argo Navis. Antlia Dwarf is a Dwarf elliptical galaxy. It lies 43 Mly from Earth in the constellation Antlia. Antlia ( Pump, from Ancient Greek: ἀντλία - antlia "bilge-water filth" is a relatively new constellation as it was only Leo I is a Dwarf spheroidal galaxy in the Constellation Leo. At about 820000 Light-years distant it is a member of the Local Group Leo I is a Dwarf spheroidal galaxy in the Constellation Leo. At about 820000 Light-years distant it is a member of the Local Group The Sextans Dwarf Spheroidal is a Dwarf spheroidal galaxy that was discovered in 1990 by Mike Irwin M Leo B (or Leo II) is an dwarf spheroidal Galaxy of the Local Group, part of the Milky Way subgroup in the Constellation of Leo B (or Leo II) is an dwarf spheroidal Galaxy of the Local Group, part of the Milky Way subgroup in the Constellation of The Ursa Minor Dwarf Dwarf elliptical galaxy was discovered by A The Draco Dwarf is a spheroidal galaxy which was discovered by Albert George Wilson of Lowell Observatory in 1954 on photographic plates of the Draco (ˈdreɪkoʊ Dragon) is a far northern Constellation that is circumpolar for many Northern hemisphere observers The Sagittarius Dwarf Elliptical Galaxy ( SagDEG) is an elliptically looped shaped Satellite galaxy of the Milky Way Galaxy. The Sagittarius Dwarf Elliptical Galaxy ( SagDEG) is an elliptically looped shaped Satellite galaxy of the Milky Way Galaxy. The Tucana Dwarf Galaxy is a Dwarf galaxy in the Constellation Tucana. The Cassiopeia Dwarf (also known as Andromeda VII) is a Dwarf spheroidal galaxy about 2 The Cassiopeia Dwarf (also known as Andromeda VII) is a Dwarf spheroidal galaxy about 2 The Pegasus Dwarf Spheroidal (also known as Andromeda VI or Peg dSph for short is a Dwarf spheroidal galaxy about 2 The Pegasus Dwarf Spheroidal (also known as Andromeda VI or Peg dSph for short is a Dwarf spheroidal galaxy about 2 Ursa Major ( is a Constellation visible throughout the year in most of the northern hemisphere The Virgo Stellar Stream (also known as Virgo Overdensity, Virgo Dwarf Galaxy, or Virgo super star cluster) is the proposed Virgo ( Virgin, symbol, Unicode ♍ is a Constellation of the Zodiac. Willman 1 or SDSS J1049+5103 discovered by a team lead by Beth Willman of New York University, using Sloan Digital Sky Survey data Andromeda IV (And IV might be an irregular satellite of the Andromeda Galaxy, but is probably not a Galaxy at all but just a loose UGCA 86 is an Irregular galaxy within the IC 342/Maffei Group. Camelopardalis ( from Ancient Greek καμηλοπάρδαλις - kamēlopardalis Giraffe) is the name of a large but faint northern UGC 8091 (also known as GR 8) is a gas-rich dwarf irregular Galaxy. UGC 8091 (also known as GR 8) is a gas-rich dwarf irregular Galaxy. Virgo ( Virgin, symbol, Unicode ♍ is a Constellation of the Zodiac. IC 5152 is an Irregular galaxy 58 million Light years from Earth in the Indus Constellation. Indus (ˈɪndəs is a southern Constellation that represents a native of the Americas. NGC 55 is a Barred irregular galaxy located about 7 million Light-years away in the Constellation Sculptor. Sculptor (ˈskʌlptɚ is a minor southern Constellation which was introduced by Nicolas Louis de Lacaille. The Aquarius Dwarf Galaxy is a Dwarf galaxy and an Irregular galaxy, that was first catalogued in 1966 by the DDO survey. The Aquarius Dwarf Galaxy is a Dwarf galaxy and an Irregular galaxy, that was first catalogued in 1966 by the DDO survey. Aquarius ( Water -bearer or cup-bearer is the eleventh sign of the Zodiac, situated between Capricornus and Pisces. NGC 404 is a small Galaxy visible in amateur telescopes near the star Mirach in the Constellation Andromeda. NGC 1569 is a dwarf Irregular galaxy in Camelopardalis. While this faint galaxy is not a popular amateur astronomy target it is well studied by professional Grus (ˈgrʌs/ /ˈgruːs crane) is a southern Constellation. The constellation was one of twelve constellations created by Pieter Dirkszoon Keyser and Palomar 12 is a Globular cluster in the Constellation Capricornus that belongs to the halo of the Milky Way galaxy Palomar 12 is a Globular cluster in the Constellation Capricornus that belongs to the halo of the Milky Way galaxy Capricornus ( Latin for "horned (male Goat " or "goat horn " is one of the Constellations of the Zodiac. A globular cluster is a spherical collection of Stars that orbits a galactic core as a Satellite. Palomar 4 is a Globular cluster of the Milky Way Galaxy. It was discovered in 1949 by Edwin Hubble and again in 1955 Smith's Cloud is a High velocity cloud of Hydrogen gas located in the constellation Aquila at Galactic coordinates l  = 39° Interstellar cloud is the generic name given to an accumulation of gas plasma and dust in our and other galaxies.
• HVC 127-41-330 - High velocity cloud, 2. HVC 127-41-330 is a High velocity cloud located at that galactic longitude latitude and velocity towards Earth Interstellar cloud is the generic name given to an accumulation of gas plasma and dust in our and other galaxies. 3 million light-years from Earth

See also

• Groups and clusters of galaxies
• List of nearest galaxies
• List of galaxy clusters
• Local Supercluster

References

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
• van den Bergh, Sidney (2000). "Updated Information on the Local Group". The Publications of the Astronomical Society of the Pacific 112 (770): 529-536.