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Sculptor Dwarf Irregular Galaxy
The Sculptor Dwarf Irregular Galaxy (SDIG) is an irregular galaxy in the constellation Sculptor. It is a member of the NGC 7793 subgroup of the Sculptor Group. The galaxy was discovered in 1976. __NOTOC__ Nearby galaxies and galaxy group information The Sculptor Dwarf Irregular Galaxy and the dwarf galaxy UGCA 442 are both companions of the spiral galaxy NGC 7793. These galaxies all lie within the Sculptor Group, a weakly bound, filament-like group of galaxies located near the Local Group. See also * Sculptor Dwarf Galaxy The Sculptor Dwarf Galaxy (also known as Sculptor Dwarf Elliptical Galaxy or the Sculptor Dwarf Spheroidal Galaxy, and formerly as the Sculptor System) is a dwarf spheroidal galaxy that is a satellite of the Milky Way. The galaxy lies within the ... – a dwarf spheroidal or elliptical galaxy, also in Sculptor, but significantly closer; a satellite of the Milky Way. References External links * Dwarf irregular galaxies Sculptor Group Sculptor (cons ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sculptor Galaxy
The Sculptor Galaxy (also known as the Silver Coin, Silver Dollar Galaxy, NGC 253, or Caldwell 65) is an intermediate spiral galaxy in the constellation Sculptor. The Sculptor Galaxy is a starburst galaxy, which means that it is currently undergoing a period of intense star formation. Observation Observational history The galaxy was discovered by Caroline Herschel in 1783 during one of her systematic comet searches. About half a century later, John Herschel observed it using his 18-inch metallic mirror reflector at the Cape of Good Hope. He wrote: "very bright and large (24′ in length); a superb object.... Its light is somewhat streaky, but I see no stars in it except 4 large and one very small one, and these seem not to belong to it, there being many near..." In 1961, Allan Sandage wrote in the ''Hubble Atlas of Galaxies'' that the Sculptor Galaxy is "the prototype example of a special subgroup of Sc systems....photographic images of galaxies of the group are dominated by t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sculptor Group
The Sculptor Group is a loose group of galaxies visible near the south galactic pole. The group is one of the closest groups of galaxies to the Local Group; the distance to the center of the group from the Milky Way is approximately . The Sculptor Galaxy (NGC 253) and a few other galaxies form a gravitationally-bound core in the center of this group. A few other galaxies at the periphery may be associated with the group but may not be gravitationally bound. Because most of the galaxies in this group are actually weakly gravitationally bound, the group may also be described as a filament. It is considered to be at an early stage of evolution in which galaxies are still falling into the group along filamentary structures. Members The table below lists galaxies that have been identified as associated with the Sculptor Galaxy (and hence associated with the group) by I. D. Karachentsev and collaborators. The object names used in the above table differ from the names used by Kar ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dwarf Irregular Galaxies
An irregular galaxy is a galaxy that does not have a distinct regular shape, unlike a Spiral galaxy, spiral or an elliptical galaxy. Irregular galaxies do not fall into any of the regular classes of the Hubble sequence, and they are often chaotic in appearance, with neither a bulge (astronomy), nuclear bulge nor any trace of spiral arm structure. Collectively they are thought to make up about a quarter of all galaxies. Some irregular galaxies were once spiral or elliptical galaxies but were deformed by an uneven external gravitational force. Irregular galaxies may contain abundant amounts of gas and dust. This is not necessarily true for dwarf irregulars. Irregular galaxies are commonly small, about one tenth the mass of the Milky Way galaxy. Due to their small sizes, they are prone to environmental effects like crashing with large galaxies and intergalactic clouds. Types There are three major types of irregular galaxies: * An Irr-I galaxy (Irr I) is an irregular galaxy that f ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Local Group
The Local Group is the galaxy group that includes the Milky Way. It has a total diameter of roughly , and a total mass of the order of . It consists of two collections of galaxies in a "dumbbell" shape: the Milky Way and its satellites form one lobe, and the Andromeda Galaxy and its satellites constitute the other. The two collections are separated by about and are moving toward one another with a velocity of . The group itself is a part of the larger Virgo Supercluster, which may be a part of the Laniakea Supercluster. The exact number of galaxies in the Local Group is unknown as some are occluded by the Milky Way; however, at least 80 members are known, most of which are dwarf galaxies. The two largest members, the Andromeda Galaxy and the Milky Way, are both spiral galaxies with masses of about solar masses each. Each has its own system of satellite galaxies: * The Andromeda Galaxy's satellite system consists of Messier 32 (M32), Messier 110 (M110), NGC 147, NGC 185, A ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Group Of Galaxies
A galaxy group or group of galaxies (GrG) is an aggregation of galaxies comprising about 50 or fewer gravitationally bound members, each at least as luminous as the Milky Way (about 1010 times the luminosity of the Sun); collections of galaxies larger than groups that are first-order clustering are called galaxy clusters. The groups and clusters of galaxies can themselves be clustered, into superclusters of galaxies. The Milky Way galaxy is part of a group of galaxies called the Local Group. Characteristics Groups of galaxies are the smallest aggregates of galaxies. They typically contain no more than 50 galaxies in a diameter of 1 to 2 megaparsecs (Mpc).see 1022 m for distance comparisons Their mass is approximately 1013 solar masses. The spread of velocities for the individual galaxies is about 150 km/s. However, this definition should be used as a guide only, as larger and more massive galaxy systems are sometimes classified as galaxy groups. Groups are the most commo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Spiral Galaxy
Spiral galaxies form a class of galaxy originally described by Edwin Hubble in his 1936 work ''The Realm of the Nebulae''Alt URL pp. 124–151) and, as such, form part of the . Most spiral galaxies consist of a flat, rotating containing s, gas and dust, and a central concentration of stars known as the |
UGCA 442
The Uppsala General Catalogue of Galaxies (UGC) is a catalogue of 12,921 galaxies visible from the northern hemisphere. It was first published in 1973. The catalogue includes essentially all galaxies north of declination In astronomy, declination (abbreviated dec; symbol ''δ'') is one of the two angles that locate a point on the celestial sphere in the equatorial coordinate system, the other being hour angle. Declination's angle is measured north or south of the ... -02°30' and to a limiting diameter of 1.0 arcminute or to a limiting apparent magnitude of 14.5. The primary source of data is the blue prints of the Palomar Observatory Sky Survey (POSS). It also includes galaxies smaller than 1.0 arcminute in diameter but brighter than 14.5 magnitude from the Catalogue of Galaxies and of Clusters of Galaxies (CGCG). The catalogue contains descriptions of the galaxies and their surrounding areas, plus conventional system classifications and position angles for flattened gala ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dwarf Galaxy
A dwarf galaxy is a small galaxy composed of about 1000 up to several billion stars, as compared to the Milky Way's 200–400 billion stars. The Large Magellanic Cloud, which closely orbits the Milky Way and contains over 30 billion stars, is sometimes classified as a dwarf galaxy; others consider it a full-fledged galaxy. Dwarf galaxies' formation and activity are thought to be heavily influenced by interactions with larger galaxies. Astronomers identify numerous types of dwarf galaxies, based on their shape and composition. Formation One theory states that most galaxies, including dwarf galaxies, form in association with dark matter, or from gas that contains metals. However, NASA's Galaxy Evolution Explorer space probe identified new dwarf galaxies forming out of gases with low metallicity. These galaxies were located in the Leo Ring, a cloud of hydrogen and helium around two massive galaxies in the constellation Leo. Because of their small size, dwarf galaxies have ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
NGC 7793
NGC 7793 is a flocculent spiral galaxy in the southern constellation of Sculptor. It was discovered in 1826 by Scottish astronomer James Dunlop. The galaxy is located at a distance of million light years and is receding with a heliocentric radial velocity of . NGC 7793 is one of the five brightest galaxies within the Sculptor Group. The morphological class of NGC 7793 is SA(s)d, indicating it is unbarred spiral galaxy (SA) with no inner ring structure (s) and the arms are loosely wound and disorganized (d). It is flocculent in appearance with a very small bulge and a star cluster at the nucleus. The galactic disk is inclined at an angle of 53.7° to the line of sight from the Earth. The visible profile is elliptical in form with an angular size of and a major axis aligned along a position angle of 99.3°. There are two nearby dwarf galaxy companions. On March 25, 2008, a type II-P supernova designated SN 2008bk was discovered in NGC 7793. At apparent magnitude 12.5, it be ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sculptor Dwarf Galaxy
The Sculptor Dwarf Galaxy (also known as Sculptor Dwarf Elliptical Galaxy or the Sculptor Dwarf Spheroidal Galaxy, and formerly as the Sculptor System) is a dwarf spheroidal galaxy that is a satellite of the Milky Way. The galaxy lies within the constellation Sculptor (constellation), Sculptor. It was discovered in 1937 by American astronomer Harlow Shapley using the 24-inch Bruce refractor at Boyden Observatory. The galaxy is located about 290,000 light-years away from the Solar System. The Sculptor Dwarf contains only 4 percent of the carbon and other heavy elements in our own galaxy, the Milky Way, making it similar to primitive galaxies seen at the edge of the universe. Metallicity The metallicity of Sculptor dwarf appears to be broken up into two distinct groups, one with [Fe/H] = −2.3 and the other with [Fe/H] = −1.5. Similar to many of the other Local Group galaxies, the older metal-poor segment appears more extended than the younger metal-rich segment. Using cosmologi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Constellation
A constellation is an area on the celestial sphere in which a group of visible stars forms Asterism (astronomy), a perceived pattern or outline, typically representing an animal, mythological subject, or inanimate object. The origins of the earliest constellations likely go back to prehistory. People used them to relate stories of their beliefs, experiences, creation myth, creation, or mythology. Different cultures and countries adopted their own constellations, some of which lasted into the early 20th century before today's constellations were internationally recognized. The recognition of constellations has changed significantly over time. Many changed in size or shape. Some became popular, only to drop into obscurity. Some were limited to a single culture or nation. The 48 traditional Western constellations are Greek. They are given in Aratus' work ''Phenomena'' and Ptolemy's ''Almagest'', though their origin probably predates these works by several centuries. Constellation ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Irregular Galaxy
An irregular galaxy is a galaxy that does not have a distinct regular shape, unlike a spiral or an elliptical galaxy. Irregular galaxies do not fall into any of the regular classes of the Hubble sequence, and they are often chaotic in appearance, with neither a nuclear bulge nor any trace of spiral arm structure. Collectively they are thought to make up about a quarter of all galaxies. Some irregular galaxies were once spiral or elliptical galaxies but were deformed by an uneven external gravitational force. Irregular galaxies may contain abundant amounts of gas and dust. This is not necessarily true for dwarf irregulars. Irregular galaxies are commonly small, about one tenth the mass of the Milky Way galaxy. Due to their small sizes, they are prone to environmental effects like crashing with large galaxies and intergalactic clouds. Types There are three major types of irregular galaxies: * An Irr-I galaxy (Irr I) is an irregular galaxy that features some structure but not ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
