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NGC 4570
NGC 4570 is an edge-on lenticular galaxy located about 57 million light-years away in the constellation Virgo. NGC 4570 was discovered by astronomer William Herschel on April 13, 1784 and is a member of the Virgo Cluster. Structure NGC 4570 has a nuclear disc that extends to a radius of about ~. In between the nuclear disk and the surrounding two stellar rings and the outer disk, there is a gap that separates the outer edge of the nuclear disk and the inner edge of the main disk by about ~. This multi-disc structure may have been shaped through secular evolution induced by a small nuclear bar. However, observations of the globular clusters surrounding NGC 4570 have found a significant population with ages ranging from about 1–3 billion years. Surprisingly, the estimated ages of the young globular clusters appears to be in good agreement with the estimated age of the stellar population of the nuclear disc (≤2 Gyr). This suggests that the young globular clusters and the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
New General Catalogue
The ''New General Catalogue of Nebulae and Clusters of Stars'' (abbreviated NGC) is an astronomical catalogue of deep-sky objects compiled by John Louis Emil Dreyer in 1888. The NGC contains 7,840 objects, including galaxies, star clusters and emission nebulae. Dreyer published two supplements to the NGC in 1895 and 1908, known as the ''Index Catalogues'' (abbreviated IC), describing a further 5,386 astronomical objects. Thousands of these objects are best known by their NGC or IC numbers, which remain in widespread use. The NGC expanded and consolidated the cataloguing work of William and Caroline Herschel, and John Herschel's ''General Catalogue of Nebulae and Clusters of Stars''. Objects south of the celestial equator are catalogued somewhat less thoroughly, but many were included based on observation by John Herschel or James Dunlop. The NGC contained multiple errors, but attempts to eliminate them were made by the ''Revised New General Catalogue'' (RNGC) by Jack W. Sulent ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Accretion (astrophysics)
In astrophysics, accretion is the accumulation of particles into a massive object by gravitationally attracting more matter, typically gaseous matter, in an accretion disk. Most astronomical objects, such as galaxies, stars, and planets, are formed by accretion processes. Overview The accretion model that Earth and the other terrestrial planets formed from meteoric material was proposed in 1944 by Otto Schmidt, followed by the ''protoplanet theory'' of William McCrea (1960) and finally the ''capture theory'' of Michael Woolfson. For details of Kant's position, see In 1978, Andrew Prentice resurrected the initial Laplacian ideas about planet formation and developed the ''modern Laplacian theory''. None of these models proved completely successful, and many of the proposed theories were descriptive. The 1944 accretion model by Otto Schmidt was further developed in a quantitative way in 1969 by Viktor Safronov. He calculated, in detail, the different stages of terrestrial plane ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
UGC Objects
UGC may refer to: Science and technology * Universal gravitational constant G, in physics * Uppsala General Catalogue, an astronomical catalogue of galaxies * UGC, a codon for cysteine * Unique games conjecture In computational complexity theory, the unique games conjecture (often referred to as UGC) is a conjecture made by Subhash Khot in 2002. The conjecture postulates that the problem of determining the approximate ''value'' of a certain type of gam ..., a conjecture in computational complexity Organisations * UGC (cinema operator), a European cinema chain, formerly Union Générale Cinématographique * UGC Fox Distribution, a former French-American film production company formed in 1995 * Union Graduate College, Schenectady, New York * United Grain Company, a Russian grain trading company based in Moscow * University Grants Commission (other) * University Grants Committee (other) * UnitedGlobalCom, former name of the cable TV operator Liberty Global * Un ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Principal Galaxies Catalogue Objects
Principal may refer to: Title or rank * Principal (academia), the chief executive of a university ** Principal (education), the office holder/ or boss in any school * Principal (civil service) or principal officer, the senior management level in the UK Civil Service * Principal dancer, the top rank in ballet * Principal (music), the top rank in an orchestra Law * Principal (commercial law), the person who authorizes an agent ** Principal (architecture), licensed professional(s) with ownership of the firm * Principal (criminal law), the primary actor in a criminal offense * Principal (Catholic Church), an honorific used in the See of Lisbon Places * Principal, Cape Verde, a village * Principal, Ecuador, a parish Media * ''The Principal'' (TV series), a 2015 Australian drama series * ''The Principal'', a 1987 action film * Principal (music), the lead musician in a section of an orchestra * Principal photography, the first phase of movie production * "The Principal", a song on ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
NGC Objects
The ''New General Catalogue of Nebulae and Clusters of Stars'' (abbreviated NGC) is an astronomical catalogue of deep-sky objects compiled by John Louis Emil Dreyer in 1888. The NGC contains 7,840 objects, including galaxies, star clusters and emission nebulae. Dreyer published two supplements to the NGC in 1895 and 1908, known as the ''Index Catalogues'' (abbreviated IC), describing a further 5,386 astronomical objects. Thousands of these objects are best known by their NGC or IC numbers, which remain in widespread use. The NGC expanded and consolidated the cataloguing work of William and Caroline Herschel, and John Herschel's ''General Catalogue of Nebulae and Clusters of Stars''. Objects south of the celestial equator are catalogued somewhat less thoroughly, but many were included based on observation by John Herschel or James Dunlop. The NGC contained multiple errors, but attempts to eliminate them were made by the ''Revised New General Catalogue'' (RNGC) by Jack W. Sulenti ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lenticular Galaxies
A lenticular galaxy (denoted S0) is a type of galaxy intermediate between an elliptical (denoted E) and a spiral galaxy in galaxy morphological classification schemes. It contains a large-scale disc but does not have large-scale spiral arms. Lenticular galaxies are disc galaxies that have used up or lost most of their interstellar matter and therefore have very little ongoing star formation. They may, however, retain significant dust in their disks. As a result, they consist mainly of aging stars (like elliptical galaxies). Despite the morphological differences, lenticular and elliptical galaxies share common properties like spectral features and scaling relations. Both can be considered early-type galaxies that are passively evolving, at least in the local part of the Universe. Connecting the E galaxies with the S0 galaxies are the ES galaxies with intermediate-scale discs. Morphology and structure Classification Lenticular galaxies are unique in that they have a visibl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
NGC 5866
NGC 5866 (also called the Spindle Galaxy or Messier 102) is a relatively bright lenticular galaxy in the constellation Draco. NGC 5866 was most likely discovered by Pierre Méchain or Charles Messier in 1781, and independently found by William Herschel in 1788. Measured orbital velocities of its globular cluster system imply that dark matter makes up only 34±45% of the mass within 5 effective radii, a notable paucity. Dust lane One of the most outstanding features of NGC 5866 is the extended dust disk, which is seen almost exactly edge-on. This dust lane is highly unusual for a lenticular galaxy. The dust in most lenticular galaxies is generally found only near the nucleus and generally follows the light profile of the galaxies' bulges. This dust disk may contain a ring-like structure, although the shape of this structure is difficult to determine given the edge-on orientation of the galaxy. It is also possible that the galaxy is a spiral galaxy that was misclassified as a len ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
List Of NGC Objects (4001–5000)
This is a list of NGC objects 4001–5000 from the New General Catalogue (NGC). The astronomical catalogue is composed mainly of star clusters, nebulae, and galaxies. Other objects in the catalogue can be found in the other subpages of the list of NGC objects. The constellation information in these tables is taken from ''The Complete New General Catalogue and Index Catalogue of Nebulae and Star Clusters by Jjiko. L. E. Dreyer'', which was accessed using the "VizieR Service". Galaxy types are identified using the ''NASA/IPAC Extragalactic Database''. The other data of these tables are from the SIMBAD Astronomical Database unless otherwise stated. 4001–4100 4101–4200 4201-4300 4301–4400 4401–4500 4501–4600 4601–4700 4701–4800 4801–4900 4901–5000 See also * Lists of astronomical objects This is a list of lists, grouped by type of astronomical object. Solar System * List of Solar System objects * List of gravitationally rounded ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Starburst Galaxy
A starburst galaxy is one undergoing an exceptionally high rate of star formation, as compared to the long-term average rate of star formation in the galaxy or the star formation rate observed in most other galaxies. For example, the star formation rate of the Milky Way galaxy is approximately 3 M☉/yr, while starburst galaxies can experience star formation rates of 100 M☉ or more. In a starburst galaxy, the rate of star formation is so large that the galaxy will consume all of its gas reservoir, from which the stars are forming, on a timescale much shorter than the age of the galaxy. As such, the starburst nature of a galaxy is a phase, and one that typically occupies a brief period of a galaxy's evolution. The majority of starburst galaxies are in the midst of a merger or close encounter with another galaxy. Starburst galaxies include M82, NGC 4038/NGC 4039 (the Antennae Galaxies), and IC 10. Definition Starburst galaxies are defined by these three interrelated factors: ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Galaxy Merger
Galaxy mergers can occur when two (or more) galaxies collide. They are the most violent type of galaxy interaction. The gravitational interactions between galaxies and the friction between the gas and dust have major effects on the galaxies involved. The exact effects of such mergers depend on a wide variety of parameters such as collision angles, speeds, and relative size/composition, and are currently an extremely active area of research. Galaxy mergers are important because the merger rate is a fundamental measurement of galaxy evolution. The merger rate also provides astronomers with clues about how galaxies bulked up over time. Description During the merger, stars and dark matter in each galaxy become affected by the approaching galaxy. Toward the late stages of the merger, the gravitational potential (i.e. the shape of the galaxy) begins changing so quickly that star orbits are greatly altered, and lose any trace of their prior orbit. This process is called “violent r ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sloan Digital Sky Survey
The Sloan Digital Sky Survey or SDSS is a major multi-spectral imaging and spectroscopic redshift survey using a dedicated 2.5-m wide-angle optical telescope at Apache Point Observatory in New Mexico, United States. The project began in 2000 and was named after the Alfred P. Sloan Foundation, which contributed significant funding. A consortium of the University of Washington and Princeton University was established to conduct a redshift survey. The Astrophysical Research Consortium (ARC) was established in 1984 with the additional participation of New Mexico State University and Washington State University to manage activities at Apache Point. In 1991 the Sloan Foundation granted the ARC funding for survey efforts and the construction of equipment to carry out the work.. Background At the time of its design, the SDSS was a pioneering combination of novel instrumentation as well as data reduction and storage techniques that drove major advances in astronomical observations, di ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Billion Years Ago
bya or b.y.a. is an abbreviation for "1000000000 (number), billion years ago". It is commonly used as a unit of time to denote length of time before the present in 109 years. This Acronym#Nomenclature, initialism is often used in the sciences of astronomy, geology, and paleontology. The "billion" in bya is the 109 "billion" of the Long and short scales, short scale of the United States, U.S.,Gale, Joseph (2009). ''Astrobiology of Earth: The Emergence''. Oxford: Oxford University Press, p21./ref> not the long-scale 1012 "billion" of some European usage. Billion by this convention (109) is often called a "thousand million" in the UK and a "milliard" in some other countries.Chartrand, Mark (2004). ''Satellite Communications for the Nonspecialist''. New York: SPIE Press, p73./ref> For this reason, there is potential for some confusion, and some scientists prefer the unit Gya, while others prefer Giga-annum, Ga (Giga-annum), however bya remains in more widespread use. In 1974, the UK sw ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
