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Interacting Galaxy
Interacting galaxies (''colliding galaxies'') are galaxy, galaxies whose gravity, gravitational fields result in a disturbance of one another. Major mergers occur between galaxies with similar amounts of mass, whereas minor mergers involve galaxies with masses that vary significantly. An example of a minor interaction is a satellite galaxy disturbing the primary galaxy's spiral arms. An example of a major interaction is a galactic collision, which may lead to a galaxy merger. Satellite interaction A giant galaxy interacting with its satellite galaxy, satellites is common. A satellite's gravity could attract one of the primary's spiral arms. Alternatively, the secondary satellite can dive into the primary galaxy, as in the Sagittarius Dwarf Spheroidal Galaxy, Sagittarius Dwarf Elliptical Galaxy diving into the Milky Way. That can possibly trigger a small amount of star formation. Such orphaned clusters of stars were sometimes referred to as "blue blobs" before they were recognize ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
NGC 3169 NGC 3166
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] |
Galaxy Cluster
A galaxy cluster, or a cluster of galaxies, is a structure that consists of anywhere from hundreds to thousands of galaxies that are bound together by gravity, with typical masses ranging from 1014 to 1015 solar masses. Clusters consist of galaxies, heated gas, and dark matter. They are the second-largest known gravitationally bound structures in the universe after superclusters. They were believed to be the largest known structures in the universe until the 1980s, when superclusters were discovered. Small aggregates of galaxies are referred to as galaxy groups rather than clusters of galaxies. Together, galaxy groups and clusters form superclusters. Basic properties Galaxy clusters typically have the following properties: * They contain 100 to 1,000 galaxies, hot X-ray emitting gas and large amounts of dark matter. Details are described in the "Composition" section. * They have total masses of 1014 to 1015 solar masses. * They typically have diameters from 1 to 5 Mpc ( ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
The Astrophysical Journal
''The Astrophysical Journal'' (''ApJ'') is a peer-reviewed scientific journal of astrophysics and astronomy, established in 1895 by American astronomers George Ellery Hale and James Edward Keeler. The journal discontinued its print edition and became an electronic-only journal in 2015. Since 1953, ''The Astrophysical Journal Supplement Series'' (''ApJS'') has been published in conjunction with ''The Astrophysical Journal'', with generally longer articles to supplement the material in the journal. It publishes six volumes per year, with two 280-page issues per volume. ''The Astrophysical Journal Letters'' (''ApJL''), established in 1967 by Subrahmanyan Chandrasekhar as Part 2 of ''The Astrophysical Journal'', is now a separate journal focusing on the rapid publication of high-impact astronomical research. The three journals were published by the University of Chicago Press for the American Astronomical Society until, in January 2009, publication was transferred to IOP Publis ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
LEDA 2108986
LEDA 2108986, also known by its Case Western Reserve University designation "Case Galaxy 611" (CG 611), is an extremely isolated, early-type dwarf galaxy with an embedded spiral structure residing in what is likely an intermediate-scale disk. The galaxy was discovered in 1987 by Sanduleak and Pesch, and is located at a distance of about in the Boötes Void and has no significant neighbours within 2.5 Mpc. The galaxy may be a counterpart to the rectangular-shaped galaxy LEDA 74886, in that they both appear to contain an intermediate-scale disk. In the case of LEDA 74886, that disk is orientated edge-on to our line-of-sight. The "early-type galaxy" class is commonly known to contain elliptical galaxies An elliptical galaxy is a type of galaxy with an approximately ellipsoidal shape and a smooth, nearly featureless image. They are one of the three main classes of galaxy described by Edwin Hubble in his Hubble sequence and 1936 work ''The Re ... (E) with no substantial ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Astronomy & Astrophysics
''Astronomy & Astrophysics (A&A)'' is a monthly peer-reviewed scientific journal covering theoretical, observational, and instrumental astronomy and astrophysics. It is operated by an editorial team under the supervision of a board of directors representing 27 sponsoring countries plus a representative of the European Southern Observatory. The journal is published by EDP Sciences and the current editors-in-chief are Thierry Forveille and João Alves. History Origins ''Astronomy & Astrophysics'' was created as an answer to the publishing situation found in Europe in the 1960s. At that time, multiple journals were being published in several countries around the continent. These journals usually had a limited number of subscribers, and articles were written in languages other than English. They were less widely read than American and British journals and the research they reported had therefore less impact in the community. Starting in 1963, conversations between astronomers from ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Disc Galaxy
A disc galaxy (or disk galaxy) is a galaxy characterized by a galactic disc. This is a flattened circular volume of stars that are mainly orbiting the galactic core in the same plane. These galaxies may or may not include a central non-disc-like region (a galactic bulge). They will typically have an orbiting mass of gas and dust in the same plane as the stars. Interacting galaxy, Interactions with other nearby galaxies can perturb and stretch the galactic disk. Disc galaxy types include: * Spiral galaxy, Spiral galaxies: ** Unbarred spiral galaxy, Unbarred spiral galaxies: (types S, SA) ** Barred spiral galaxy, Barred spiral galaxies: (type SB) ** Intermediate spiral galaxy, Intermediate spiral galaxies: (type SAB) * Lenticular galaxy, Lenticular galaxies: (types E8, S0, SA0, SB0, SAB0) Galaxies that are not disc types include: * Elliptical galaxy, Elliptical galaxies: (type dE) * Irregular galaxy, Irregular galaxies: (type dI) See also * thick disk * thin disk References [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dwarf Elliptical Galaxy
Dwarf elliptical galaxies (dEs) are elliptical galaxies that are smaller than ordinary elliptical galaxies. They are quite common in galaxy groups and clusters, and are usually companions to other galaxies. Examples "Dwarf elliptical" galaxies should not be confused with the rare "compact elliptical" galaxy class, of which M32, a satellite of the Andromeda Galaxy, is the prototype. In 1944 Walter Baade confirmed dwarf ellipticals NGC 147 and NGC 185 as members of the Local Group by resolving them into individual stars, thanks to their relatively little distance. In the 1950s, dEs were also discovered in the nearby Fornax and Virgo clusters. Relation to other elliptical galaxy types Dwarf elliptical galaxies have blue absolute magnitudes within the range fainter than ordinary elliptical galaxies. The surface brightness profiles of ordinary elliptical galaxies was formerly approximated using ''de Vaucouleur's model'', while dEs were approximated with an exponentia ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dwarf Spheroidal Galaxy
A dwarf spheroidal galaxy (dSph) is a term in astronomy applied to small, low-luminosity galaxies with very little dust and an older stellar population. They are found in the Local Group as companions to the Milky Way and as systems that are companions to the Andromeda Galaxy (M31). While similar to dwarf elliptical galaxies in appearance and properties such as little to no gas or dust or recent star formation, they are approximately spheroidal in shape and generally have lower luminosity. Discovery Despite the radii of dSphs being much larger than those of globular clusters, they are much more difficult to find due to their low luminosities and surface brightnesses. Dwarf spheroidal galaxies have a large range of luminosities, and known dwarf spheroidal galaxies span several orders of magnitude of luminosity. Their luminosities are so low that Ursa Minor, Carina, and Draco, the known dwarf spheroidal galaxies with the lowest luminosities, have mass-to-light ratios (M/L) ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Angular Momentum
Angular momentum (sometimes called moment of momentum or rotational momentum) is the rotational analog of Momentum, linear momentum. It is an important physical quantity because it is a Conservation law, conserved quantity – the total angular momentum of a closed system remains constant. Angular momentum has both a direction (geometry), direction and a magnitude, and both are conserved. Bicycle and motorcycle dynamics, Bicycles and motorcycles, flying discs, Rifling, rifled bullets, and gyroscopes owe their useful properties to conservation of angular momentum. Conservation of angular momentum is also why hurricanes form spirals and neutron stars have high rotational rates. In general, conservation limits the possible motion of a system, but it does not uniquely determine it. The three-dimensional angular momentum for a point particle is classically represented as a pseudovector , the cross product of the particle's position vector (relative to some origin) and its mo ... [...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☉/yr or more. In a starburst galaxy, the rate of star formation is so large that the galaxy consumes 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 factor ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Barred Spiral Galaxy
A barred spiral galaxy is a spiral galaxy with a central bar-shaped structure composed of stars. Bars are found in about two thirds of all spiral galaxies in the local universe, and generally affect both the motions of stars and interstellar gas within spiral galaxies and can affect spiral arms as well. The Milky Way Galaxy, where the Solar System is located, is classified as a barred spiral galaxy. Edwin Hubble classified spiral galaxies of this type as "SB" (spiral, barred) in his Hubble sequence and arranged them into sub-categories based on how open the arms of the spiral are. SBa types feature tightly bound arms, while SBc types are at the other extreme and have loosely bound arms. SBb-type galaxies lie in between the two. SB0 is a barred lenticular galaxy. A new type, SBm, was subsequently created to describe somewhat Barred irregular galaxy, irregular barred spirals, such as the Magellanic Clouds, which were once classified as irregular galaxies, but have since been found t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Computer Simulation
Computer simulation is the running of a mathematical model on a computer, the model being designed to represent the behaviour of, or the outcome of, a real-world or physical system. The reliability of some mathematical models can be determined by comparing their results to the real-world outcomes they aim to predict. Computer simulations have become a useful tool for the mathematical modeling of many natural systems in physics (computational physics), astrophysics, climatology, chemistry, biology and manufacturing, as well as human systems in economics, psychology, social science, health care and engineering. Simulation of a system is represented as the running of the system's model. It can be used to explore and gain new insights into new technology and to estimate the performance of systems too complex for analytical solutions. Computer simulations are realized by running computer programs that can be either small, running almost instantly on small devices, or large-scale ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
