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Low-surface-brightness Galaxy
A low-surface-brightness galaxy, or LSB galaxy, is a diffuse galaxy with a surface brightness that, when viewed from Earth, is at least one magnitude lower than the ambient night sky. Most LSBs are dwarf galaxy, dwarf galaxies, and most of their baryonic matter is in the form of neutral gaseous hydrogen, rather than stars. They appear to have over 95% of their mass as non-baryonic dark matter. There appears to be little supernova (SN) activity in these galaxies, although LSB galaxy IC 217 hosted 2014cl. Rotation curve measurements indicate an extremely high mass-to-light ratio, meaning that stars and luminous gas contribute only very little to the overall mass balance of an LSB. The centers of LSBs show no large overdensities in stars, unlike e.g. the bulge (astronomy), bulges of normal spiral galaxies. Therefore, they seem to be dark matter, dark-matter-dominated even in their centers, which makes them excellent laboratories for the study of dark matter. In comparison to the h ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
NGC 45 GALEX WikiSky
NGC may refer to: Companies * NGC Corporation, the name of US electric company Dynegy, Inc. from 1995 to 1998 * National Gas Company of Trinidad and Tobago, a state-owned natural gas company in Trinidad and Tobago * National Grid plc, a former name of National Grid Electricity Transmission plc, the operator of the British electricity transmission system * Northrop Grumman Corporation, an aerospace and defense conglomerate formed from the merger of Northrop Corporation and Grumman Corporation in 1994 * Numismatic Guaranty Company, a coin certification company in the United States * National Garden Clubs, headquartered in St. Louis, Missouri * Network General, Network General Corporation, a defunct networking hardware company Other uses * National Gallery of Canada, an art gallery founded in 1880 in Ottawa, Canada * National Games of China, the national multi-sport event of China * National Geographic (American TV channel), a documentary and reality television channel established in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Active Galactic Nuclei
An active galactic nucleus (AGN) is a compact region at the center of a galaxy that emits a significant amount of energy across the electromagnetic spectrum, with characteristics indicating that this luminosity is not produced by the stars. Such excess, non-stellar emissions have been observed in the radio, microwave, infrared, optical, ultra-violet, X-ray and gamma ray wavebands. A galaxy hosting an AGN is called an active galaxy. The non-stellar radiation from an AGN is theorized to result from the accretion of matter by a supermassive black hole at the center of its host galaxy. Active galactic nuclei are the most luminous persistent sources of electromagnetic radiation in the universe and, as such, can be used as a means of discovering distant objects; their evolution as a function of cosmic time also puts constraints on models of the cosmos. The observed characteristics of an AGN depend on several properties such as the mass of the central black hole, the rate of gas accret ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Phoenix Dwarf
The Phoenix Dwarf is a dwarf irregular galaxy discovered in 1976 by Hans-Emil Schuster and Richard Martin West and mistaken for a globular cluster. It is currently 1.44 Mly away from Earth. Its name comes from the fact that it is part of the Phoenix constellation. Characteristics The Phoenix Dwarf has an inner part of young stars which is stretched in an east-west direction and an outer part of mainly old stars that is stretched north-south. The central region's rate of star formation seems to have been relatively constant across time (Martínez-Delgado et al. 1999). In 1999, St-Germain et al. discovered a H I region of about 105 just to the west of Phoenix. Its radial velocity The radial velocity or line-of-sight velocity of a target with respect to an observer is the rate of change of the vector displacement between the two points. It is formulated as the vector projection of the target-observer relative velocity ... is −23 km/s and may be physically ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Malin 2
Malin may refer to: Places * Malin, Homalin, a village in Sagaing Region, Burma * Rivière du Malin (Malin River), Quebec, Canada * Malin, Xinning (), a Yao ethnic township of Xinning County, Hunan, China * Malin Head, the northernmost point of Ireland * Malin, County Donegal, Ireland, the village that gives its name to Malin Head * Malin Sea, north of Ireland * Malin, Poland, a village in Lower Silesia * Malin, a village in Nușeni Commune, Bistriţa-Năsăud County, Romania * Malyn, sometimes spelled Malin, a city in Zhytomyr Oblast of Ukraine * Malyn (Malin), a village in Mlyniv Raion in Rivne Oblast of Ukraine * Malin, Oregon, United States, a city ** Malin Airport * Malin Valley, Victoria Land, Antarctica * Malin 1, a galaxy * 4766 (1987 FF1) Malin, an asteroid - see List of minor planets: 4001–5000 People * Malin (given name), a feminine Swedish given name * Malin (surname), a surname * Malin people, an ethnic group in Burma Fictional and mythical charact ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Eridanus II
The Eridanus II Dwarf is a low-surface brightness dwarf galaxy in the constellation Eridanus. Eridanus II was independently discovered by two groups in 2015, using data from the Dark Energy Survey ( Bechtol et al., 2015; Koposov et al. 2015). This galaxy is probably a distant satellite of the Milky Way ( Li et al., 2016). Eridanus II contains a centrally located globular cluster; and is the smallest, least luminous galaxy known to contain a globular cluster. Crnojević et al., 2016. Eridanus II is significant, in a general sense, because the widely accepted Lambda CDM cosmology predicts the existence of many more dwarf galaxies than have yet been observed. The search for just such bodies was one of the motivations for the ongoing Dark Energy Survey observations. Eridanus II has special significance because of its apparently stable globular cluster. The stability of this cluster, near the center of such a small, diffuse, galaxy places constraints on the nature of dark matter ( ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
NGC 45
NGC 45 is a low surface brightness spiral galaxy in the equatorial constellation of Cetus. It was discovered on 11 November 1835 by the English astronomer John Herschel. The galaxy is located at a distance of 22 million light years and is receding with a heliocentric radial velocity of . It is located in the vicinity of the Sculptor Group, but is most likely a background galaxy. The morphological class of NGC 45 is SA(s)dm, indicating this is a spiral galaxy with no prominent inner bar (SA) or ring (s) feature. There is no central bulge to speak of. The galactic plane is inclined at an angle of to the line of sight from the Earth, with the major axis of the elliptical profile being aligned along a position angle of . Star formation is proceeding at a modest rate of ·yr−1. Unlike the Milky Way, NGC 45 has no clearly defined spiral arms, and its center bar nucleus is also very small and distorted. NGC 45 thus does not have a galactic habitable zone. For the Milk ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
IC 10
IC 10 is an irregular galaxy in the constellation Cassiopeia. It was discovered by American astronomer Lewis Swift on 8 October 1887. In 1935 Nicholas Mayall became the first to suggest that the object is extragalactic. Edwin Hubble suspected it might belong to the Local Group of galaxies, but its status remained uncertain for decades. The radial velocity of IC 10 was measured in 1962, and it was found to be approaching the Milky Way at approximately 350 km/s, strengthening the evidence for its membership in the Local Group. Its membership in the group was finally confirmed in 1996 by direct measurements of its distance based on observations of Cepheids; most estimates place the galaxy 2–3 million light years from Earth, with some estimates ranging from 1.5–4.5 million light years. Despite its closeness, the galaxy is rather difficult to study because it lies near the plane of the Milky Way and is therefore heavily obscured by interstellar matter. The apparent di ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Antlia Dwarf
The Antlia Dwarf is a dwarf spheroidal/irregular galaxy. It lies about 1.3 Mpc (4.3 million light-years) from Earth in the constellation Antlia. It is the fourth and faintest member of the nearby Antlia-Sextans Group of galaxies. The galaxy contains stars of all ages, contains significant amounts of gas, and has experienced recent star formation. The Antlia Dwarf is believed to be tidally interacting with the small barred spiral galaxy NGC 3109. Discovery The Antlia Dwarf was first cataloged in 1985 by H. Corwin, Gérard de Vaucouleurs, and A. de Vaucouleurs. Later in 1985 and 1987, it was noted as a possible nearby dwarf galaxy by two groups of astronomers. It was finally confirmed as a dwarf galaxy in 1997 by Alan Whiting, Mike Irwin and George Hau during a survey of the northern sky. They for the first time resolved it into stars and determined the distance to it—1.15 Mpc (the modern distance estimate is slightly larger). The same year, Antonio Aparicio, Jul ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pegasus Dwarf Spheroidal Galaxy
The Pegasus Dwarf Spheroidal (also known as ''Andromeda VI'' or ''Peg dSph'' for short) is a dwarf spheroidal galaxy about 2.7 million light-years away in the constellation Pegasus. The Pegasus Dwarf is a member of the Local Group and a satellite galaxy of the Andromeda Galaxy (M31). General information The Pegasus Dwarf Spheroidal is a galaxy with mainly metal-poor stellar populations. Its metallicity is e/H≃ −1.3. It is located at the right ascension 23h51m46.30s and declination +24d34m57.0s in the equatorial coordinate system (epoch J2000.0), and in a distance of 820 ± 20 kpc from Earth and a distance of 294 ± 8 kpc from the Andromeda Galaxy. The galaxy was discovered in 1999 by various authors on the Second Palomar Observatory Sky Survey (POSS II) films. See also * List of Andromeda's satellite galaxies * Pegasus Dwarf Irregular Galaxy (Peg DIG) * Pegasus galaxy, the Stargate Atlantis ''Stargate Atlantis'' (usually stylized in all caps and often abbreviate ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Andromeda V
Andromeda V is a dwarf spheroidal galaxy about 2.52 Mly away in the constellation Andromeda. Andromeda V was discovered by Armandroff et al. and published in 1998 after their analysis of the digitized version of the second Palomar Sky Survey. The metallicity of Andromeda V is above the average metallicity to luminosity ratio of the Local Group's dwarf galaxies. See also * List of Andromeda's satellite galaxies The Andromeda Galaxy (M31) has satellite galaxies just like the Milky Way. Orbiting M31 are at least 35 dwarf galaxies: the brightest and largest is M110, which can be seen with a basic telescope. The second-brightest and closest one to M31 is ... References External links SEDS: Dwarf Spheroidal Galaxy Andromeda VSIMBAD: And V -- Galaxy {{DEFAULTSORT:Andromeda 05 Dwarf spheroidal galaxies 3097824 Local Group Andromeda Subgroup Andromeda (constellation) ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
