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NGC 1404
NGC 1404 is an elliptical galaxy in the Southern constellation Eridanus. It was discovered on November 28, 1837, by the astronomer John Herschel. Based on the tip of the red-giant branch distance indicator, it lies at a distance of approximately 60 million light-years from the Milky Way. It is one of the brightest members of the Fornax Cluster. Characteristics As usual with most elliptical galaxies, NGC 1404 is rich in globular clusters, with a population of them that has been estimated to be around 725; however it has been proposed it could have lost most of its globular clusters due to gravitational interactions with NGC 1399, the brightest galaxy of the Fornax Cluster. Studies with the help of the X-ray telescope Chandra show too how ram-pressure stripping caused by the motion of NGC 1404 through Fornax' intracluster medium is stripping this galaxy of its hot gas, leaving behind a large trail.http://chandra.harvard.edu/photo/2004/fornax/ Fornax Cluster: Motions of Nearb ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Falling In Fornax
Falling or fallin' may refer to: * Falling (physics), movement due to gravity * Falling (accident) * Falling (execution) * Falling (sensation) People *Christine Falling (born 1963), American serial killer who murdered six children Books * ''Falling'' (Provoost novel), a 1994 novel by Anne Provoost * ''Falling'' (Howard novel), a 1999 novel by Elizabeth Jane Howard *"Falling", a 1967 poem by James Dickey Film and television * ''Falling'' (2008 film), a film by Richard Dutcher * ''Falling'' (2015 film), starring Adesua Etomi and Blossom Chukwujekwu * ''Falling'' (2020 film), an American-British-Canadian drama film * ''The Falling'' (1987 film), an American film by Deran Sarafian * ''The Falling'' (2014 film), a British film by Carol Morley *''Falling'' (Dutch: ''Vallen''), a 2001 film by Hans Herbots based on the novel by Anne Provoost *''Falling'', a 2005 ITV adaptation of the novel by Elizabeth Jane Howard *"Falling", an episode of the Adult Swim television series '' Off th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Monthly Notices Of The Royal Astronomical Society
''Monthly Notices of the Royal Astronomical Society'' (MNRAS) is a peer-reviewed scientific journal covering research in astronomy and astrophysics. It has been in continuous existence since 1827 and publishes letters and papers reporting original research in relevant fields. Despite the name, the journal is no longer monthly, nor does it carry the notices of the Royal Astronomical Society. History The first issue of MNRAS was published on 9 February 1827 as ''Monthly Notices of the Astronomical Society of London'' and it has been in continuous publication ever since. It took its current name from the second volume, after the Astronomical Society of London became the Royal Astronomical Society (RAS). Until 1960 it carried the monthly notices of the RAS, at which time these were transferred to the newly established ''Quarterly Journal of the Royal Astronomical Society'' (1960–1996) and then to its successor journal ''Astronomy & Geophysics'' (since 1997). Until 1965, MNRAS ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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 four main classes of galaxy described by Edwin Hubble in his Hubble sequence and 1936 work ''The Realm of the Nebulae'', with their intermediate scale disks, a subset of the "early-type" galaxy population. Most elliptical galaxies are composed of older, low-mass stars, with a sparse interstellar medium and minimal star formation activity, and they tend to be surrounded by large numbers of globular clusters. Elliptical galaxies are believed to make up approximately 10–15% of galaxies in the Virgo Supercluster, and they are not the dominant type of galaxy in the universe overall. They are preferentially found close to the centers of galaxy clusters. Elliptical galaxies range in size from dwarf ellipticals with tens of millions of stars, to supergiants of over one hundred trillion stars that dominate their galaxy clusters. Originally, Ed ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Spitzer Space Telescope
The Spitzer Space Telescope, formerly the Space Infrared Telescope Facility (SIRTF), was an infrared space telescope launched in 2003. Operations ended on 30 January 2020. Spitzer was the third space telescope dedicated to infrared astronomy, following IRAS (1983) and ISO (1995–1998). It was the first spacecraft to use an Earth-trailing orbit, later used by the Kepler planet-finder. The planned mission period was to be 2.5 years with a pre-launch expectation that the mission could extend to five or slightly more years until the onboard liquid helium supply was exhausted. This occurred on 15 May 2009. Without liquid helium to cool the telescope to the very low temperatures needed to operate, most of the instruments were no longer usable. However, the two shortest-wavelength modules of the IRAC camera continued to operate with the same sensitivity as before the helium was exhausted, and continued to be used into early 2020 in the Spitzer Warm Mission. During the warm mission, t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Intracluster Medium
In astronomy, the intracluster medium (ICM) is the superheated plasma that permeates a galaxy cluster. The gas consists mainly of ionized hydrogen and helium and accounts for most of the baryonic material in galaxy clusters. The ICM is heated to temperatures on the order of 10 to 100 megakelvins, emitting strong X-ray radiation. Composition The ICM is composed primarily of ordinary baryons, mainly ionised hydrogen and helium. This plasma is enriched with heavier elements, including iron. The average amount of heavier elements relative to hydrogen, known as metallicity in astronomy, ranges from a third to a half of the value in the sun. Studying the chemical composition of the ICMs as a function of radius has shown that cores of the galaxy clusters are more metal rich than at larger radii. In some clusters (e.g. the Centaurus cluster) the metallicity of the gas can rise to above that of the sun. Due to the gravitational field of clusters, metal-enriched gas ejected from supernova ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ram-pressure Stripping
Ram pressure is a pressure exerted on a body moving through a fluid medium, caused by relative bulk motion of the fluid rather than random thermal motion. It causes a drag force to be exerted on the body. Ram pressure is given in tensor form as :P_\text= \rho u_i u_j, where \rho is the density of the fluid; P_\text is the momentum flux per second in the i direction through a surface with normal in the j direction. u_i,u_j are the components of the fluid velocity in these directions. The total Cauchy stress tensor \sigma_ is the sum of this ram pressure and the isotropic thermal pressure (in the absence of viscosity). In the simple case when the relative velocity is normal to the surface, and momentum is fully transferred to the object, the ram pressure becomes :P_\text = \rho u^2. Derivation The Eulerian form of the Cauchy momentum equation for a fluid is :\rho\frac = -\vec \nabla p - \rho(\vec u \cdot \vec \nabla)\vec u + \rho \vec g for isotropic pressure p, where \v ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chandra
Chandra ( sa, चन्द्र, Candra, shining' or 'moon), also known as Soma ( sa, सोम), is the Hindu god of the Moon, and is associated with the night, plants and vegetation. He is one of the Navagraha (nine planets of Hinduism) and Dikpala (guardians of the directions). Etymology and other names The word "Chandra" literally means "bright, shining or glittering" and is used for the "Moon" in Sanskrit and other Indian languages.''Graha Sutras'' by Ernst Wilhelm, published by Kala Occult Publishers p. 51 It is also the name of various other figures in Hindu mythology, including an asura and a Suryavanshi king. It is also a common Indian name and surname. Both male and female name variations exists in many South Asian languages that originate from Sanskrit. Some of the synonyms of Chandra include ''Soma'' (distill), ''Indu'' (bright drop), ''Atrisuta'' (son of Atri), ''Shashin'' or ''Shachin'' (marked by hare), ''Taradhipa'' (lord of stars) and ''Nishakara'' (the ni ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Telescope
A telescope is a device used to observe distant objects by their emission, absorption, or reflection of electromagnetic radiation. Originally meaning only an optical instrument using lenses, curved mirrors, or a combination of both to observe distant objects, the word ''telescope'' now refers to a wide range of instruments capable of detecting different regions of the electromagnetic spectrum, and in some cases other types of detectors. The first known practical telescopes were refracting telescopes with glass lenses and were invented in the Netherlands at the beginning of the 17th century. They were used for both terrestrial applications and astronomy. The reflecting telescope, which uses mirrors to collect and focus light, was invented within a few decades of the first refracting telescope. In the 20th century, many new types of telescopes were invented, including radio telescopes in the 1930s and infrared telescopes in the 1960s. Etymology The word ''telescope'' was coin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
X-ray
An X-ray, or, much less commonly, X-radiation, is a penetrating form of high-energy electromagnetic radiation. Most X-rays have a wavelength ranging from 10 picometers to 10 nanometers, corresponding to frequencies in the range 30 petahertz to 30 exahertz ( to ) and energies in the range 145 eV to 124 keV. X-ray wavelengths are shorter than those of UV rays and typically longer than those of gamma rays. In many languages, X-radiation is referred to as Röntgen radiation, after the German scientist Wilhelm Conrad Röntgen, who discovered it on November 8, 1895. He named it ''X-radiation'' to signify an unknown type of radiation.Novelline, Robert (1997). ''Squire's Fundamentals of Radiology''. Harvard University Press. 5th edition. . Spellings of ''X-ray(s)'' in English include the variants ''x-ray(s)'', ''xray(s)'', and ''X ray(s)''. The most familiar use of X-rays is checking for fractures (broken bones), but X-rays are also used in other ways. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Brightest Cluster Galaxy
A brightest cluster galaxy (BCG) is defined as the brightest galaxy in a cluster of galaxies. BCGs include the most massive galaxies in the universe. They are generally elliptical galaxies which lie close to the geometric and kinematical center of their host galaxy cluster, hence at the bottom of the cluster potential well. They are also generally coincident with the peak of the cluster X-ray emission. Formation scenarios for BCGs include: * Cooling flow—Star formation from the central cooling flow in high density cooling centers of X-ray cluster halos. The study of accretion populations in BCGs has cast doubt over this theory and astronomers have seen no evidence of cooling flows in radiative cooling clusters. The two remaining theories exhibit healthier prospects. * Galactic cannibalism—Galaxies sink to the center of the cluster due to dynamical friction and tidal stripping. * Galactic merger—Rapid galactic mergers between several galaxies take place during cluster col ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
NGC 1399
NGC 1399 is a large elliptical galaxy in the Southern constellation Fornax (constellation), Fornax, the central galaxy in the Fornax Cluster. The galaxy is 66 million light-years away from Earth. With a diameter of 130 000 light-years, it is one of the largest galaxies in the Fornax Cluster and slightly larger than the Milky Way. William Herschel discovered this galaxy on October 22, 1835. Characteristics It is a type-cD galaxy, with a bright center and a vast, diffuse envelope surrounding it. It is also an early-type galaxy, the largest one in the Fornax Cluster. Despite their name, early-type galaxies are much older than spiral galaxies, and mostly comprise old, red-colored stars. Very little star formation occurs in these galaxies; the lack of star formation in elliptical galaxies appears to start at the center and then slowly propagates outward. Globular clusters NGC 1399 is very rich in globular clusters. The population is estimated to be between 5700 and 6500. It h ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Globular Cluster
A globular cluster is a spheroidal conglomeration of stars. Globular clusters are bound together by gravity, with a higher concentration of stars towards their centers. They can contain anywhere from tens of thousands to many millions of member stars. Their name is derived from Latin (small sphere). Globular clusters are occasionally known simply as "globulars". Although one globular cluster, Omega Centauri, was observed in antiquity and long thought to be a star, recognition of the clusters' true nature came with the advent of telescopes in the 17th century. In early telescopic observations globular clusters appeared as fuzzy blobs, leading French astronomer Charles Messier to include many of them in his catalog of astronomical objects that he thought could be mistaken for comets. Using larger telescopes, 18th-century astronomers recognized that globular clusters are groups of many individual stars. Early in the 20th century the distribution of globular clusters in the sky w ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
