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Whole Earth Blazar Telescope
The Whole Earth Blazar Telescope (WEBT) is an international consortium of astronomers created in 1997, with the aim to study a particular category of Active Galactic Nuclei (AGN) called blazars, which are characterized by strong and fast brightness variability, on time scales down to hours or less. This collaboration involves many telescopes observing at optical, near-infrared, and radio (millimetric and centimetric) wavelengths. Thanks to their different geographic location all around the world, the emission variations of the pointed source can be monitored 24 hours a day, with the observing task moving from east to west as the Earth rotates. WEBT observations are often carried out in conjunction with observations at higher frequencies, from ultraviolet to gamma rays, performed by both space and ground-based telescopes. In this way, information on blazar emission over almost the whole electromagnetic spectrum can be obtained. The multi-wavelength studies performed by the WEBT hav ... [...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 has a much-higher-than-normal luminosity over at least some portion of the electromagnetic spectrum with characteristics indicating that the luminosity is not produced by stars. Such excess non-stellar emission has 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 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
3C 66A
3C 66A is a blazar located in the constellation Andromeda. The "distance" of a far away galaxy depends on the distance measurement used. With a redshift of 0.444, light from this active galaxy is estimated to have taken around 4.5 billion years to reach Earth. But as a result of the expansion of the Universe, the present (co-moving) distance to this galaxy is about 5.4 billion light-years (1647 M pc). Even at this great distance this blazar has an apparent magnitude of about 15.5. Although 0.444 is used as the common redshift value, 0.3347 is a new strict lower limit "inferred through observing the far-UV absorption by the low-z IGM." 3C 66A underwent an optical outburst in 2007 August, as monitored by the Tuorla blazar monitoring program. The event was monitored by the Whole Earth Blazar Telescope The Whole Earth Blazar Telescope (WEBT) is an international consortium of astronomers created in 1997, with the aim to study a particular category of Active Galactic Nuclei ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
CTA 102
CTA 102, also known by its B1950 coordinates as 2230+114 (QSR B2230+114) and its J2000 coordinates as J2232+1143 (QSO J2232+1143), is a blazar-type quasar discovered in the early 1960s by a radio survey carried out by the California Institute of Technology. It has been observed by a large range of instruments since its discovery, including WMAP, EGRET, GALEX, VSOP and Parkes, and has been regularly imaged by the Very Long Baseline Array since 1995. It has also been detected in gamma rays, and a gamma-ray flare has been detected from it. In 1963 Nikolai Kardashev proposed that the then-unidentified radio source could be evidence of a Type II or III extraterrestrial civilization on the Kardashev scale. Follow-up observations were announced in 1965 by Gennady Sholomitskii, who found that the object's radio emission was varying; a public announcement of these results on April 12, 1965, caused a worldwide sensation. The idea that the emission was caused by a civilization was rejected ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
3C 371
3C 371 is a BL Lac object located in the constellation Draco. With a redshift of 0.051, this active galaxy is about 730 million light-years away. 3C 371 is a well known object, first associated with the BL Lac class by Miller in 1975, and is among the nearest and brightest BL Lacs. Optical jet emission from 3C 371 was first detected in ground-based images by Nilsson et al. in 1997, and confirmed with HST (Scarpa et al.) in 1999. The implied viewing angle may be less than 18 degrees. But no superluminal motion has been detected, despite frequent monitoring by the Very Long Baseline Array (VLBA). There are photos of this object dating back to 1895, and they suggest that this objects magnitude can vary by ±1.5. References External links * Wikiskimageof 3C 371 New X-ray Jet in Nearby BL Lacertae Object 3C371(Brandeis University Radio Astronomy) {{DEFAULTSORT:3C 371 Blazars Quasars BL Lacertae objects 371 __NOTOC__ Year 371 (CCCLXXI) was a common year start ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
3C 273
3C 273 is a quasar located in the constellation of Virgo (constellation), Virgo. It was the first quasar ever to be identified. It is the optically brightest quasar in the sky from Earth (apparent magnitude, m ~12.9), and one of the closest with a redshift, ''z'', of 0.158. A luminosity distance of DL = may be calculated from ''z''. It is also one of the most luminous quasars known, with an absolute magnitude of −26.7, meaning that if it were only as distant as Pollux (star), Pollux (~10 parsecs) it would Apparent magnitude, appear nearly as bright in the sky as the Sun. Since the Sun's absolute magnitude is 4.83, it means that the quasar is over 4 trillion times more luminosity, luminous than Solar luminosity, the Sun at visible wavelengths. The mass of its central black hole has been measured to be 886 ± 187 million solar masses through broad emission-line reverberation mapping. Large-scale jet The quasar has a large-scale visible astrophysical jet, jet, which measures ~ lo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Enrico Fermi
Enrico Fermi (; 29 September 1901 – 28 November 1954) was an Italian (later naturalized American) physicist and the creator of the world's first nuclear reactor, the Chicago Pile-1. He has been called the "architect of the nuclear age" and the "architect of the atomic bomb". He was one of very few physicists to excel in both theoretical physics and experimental physics. Fermi was awarded the 1938 Nobel Prize in Physics for his work on induced radioactivity by neutron bombardment and for the discovery of transuranium elements. With his colleagues, Fermi filed several patents related to the use of nuclear power, all of which were taken over by the US government. He made significant contributions to the development of statistical mechanics, Quantum mechanics, quantum theory, and nuclear physics, nuclear and particle physics. Fermi's first major contribution involved the field of statistical mechanics. After Wolfgang Pauli formulated his Pauli exclusion principle, exclusion pri ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fermi Gamma-ray Space Telescope
The Fermi Gamma-ray Space Telescope (FGST, also FGRST), formerly called the Gamma-ray Large Area Space Telescope (GLAST), is a space observatory being used to perform gamma-ray astronomy observations from low Earth orbit. Its main instrument is the Large Area Telescope (LAT), with which astronomers mostly intend to perform an all-sky survey studying astrophysical and cosmological phenomena such as active galactic nuclei An active galactic nucleus (AGN) is a compact region at the center of a galaxy that has a much-higher-than-normal luminosity over at least some portion of the electromagnetic spectrum with characteristics indicating that the luminosity is not prod ..., pulsars, other high-energy sources and dark matter. Another instrument aboard Fermi, the Gamma-ray Burst Monitor (GBM; formerly GLAST Burst Monitor), is being used to study gamma-ray bursts and solar flares. Fermi, named for high-energy physics pioneer Enrico Fermi, was launched on 11 June 2008 at 16:05 UTC ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Satellites
A satellite or artificial satellite is an object intentionally placed into orbit in outer space. Except for passive satellites, most satellites have an electricity generation system for equipment on board, such as solar panels or radioisotope thermoelectric generators (RTGs). Most satellites also have a method of communication to ground stations, called transponders. Many satellites use a standardized bus to save cost and work, the most popular of which is small CubeSats. Similar satellites can work together as a group, forming constellations. Because of the high launch cost to space, satellites are designed to be as lightweight and robust as possible. Most communication satellites are radio relay stations in orbit and carry dozens of transponders, each with a bandwidth of tens of megahertz. Satellites are placed from the surface to orbit by launch vehicles, high enough to avoid orbital decay by the atmosphere. Satellites can then change or maintain the orbit by propulsion, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gamma-ray
A gamma ray, also known as gamma radiation (symbol γ or \gamma), is a penetrating form of electromagnetic radiation arising from the radioactive decay of atomic nucleus, atomic nuclei. It consists of the shortest wavelength electromagnetic waves, typically shorter than those of X-rays. With frequency, frequencies above 30 exahertz (), it imparts the highest photon energy. Paul Ulrich Villard, Paul Villard, a French chemist and physicist, discovered gamma radiation in 1900 while studying radiation emitted by radium. In 1903, Ernest Rutherford named this radiation ''gamma rays'' based on their relatively strong penetration of matter; in 1900 he had already named two less penetrating types of decay radiation (discovered by Henri Becquerel) alpha particle, alpha rays and beta particle, beta rays in ascending order of penetrating power. Gamma rays from radioactive decay are in the energy range from a few kiloelectronvolts (keV) to approximately 8 megaelectronvolts (MeV), corres ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Scientific Publications
: ''For a broader class of literature, see Academic publishing.'' Scientific literature comprises scholarly publications that report original empirical and theoretical work in the natural and social sciences. Within an academic field, scientific literature is often referred to as the literature. Academic publishing is the process of contributing the results of one's research into the literature, which often requires a peer-review process. Original scientific research published for the first time in scientific journals is called the primary literature. Patents and technical reports, for minor research results and engineering and design work (including computer software), can also be considered primary literature. Secondary sources include review articles (which summarize the findings of published studies to highlight advances and new lines of research) and books (for large projects or broad arguments, including compilations of articles). Tertiary sources might include en ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
3C 279
3C 279 (also known as 4C–05.55, NRAO 413, and PKS 1253–05) is an optically violent variable quasar (OVV), which is known in the astronomical community for its variations in the visible, radio and x-ray bands. The quasar was observed to have undergone a period of extreme activity from 1987 until 1991. The Rosemary Hill Observatory (RHO) started observing 3C 279 in 1971, the object was further observed by the Compton Gamma Ray Observatory in 1991, when it was unexpectedly discovered to be one of the brightest gamma ray objects in the sky. It is also one of the brightest and most variable sources in the gamma ray sky monitored by the Fermi Gamma-ray Space Telescope. It was used as a calibrator source for Event Horizon Telescope The Event Horizon Telescope (EHT) is a large Astronomical interferometer, telescope array consisting of a global network of radio telescopes. The EHT project combines data from several very-long-baseline interferometry (VLBI) stations around Ear ... ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
3C 454
3C may refer to: In astronomy: * 3C, the ''Third Cambridge Catalogue of Radio Sources'', an astronomical reference series In business: * Long March 3C, a 2008 Chinese orbital rocket * 3C Records, a record label * 3C (radio), a defunct digital radio station * Team 3C Casalinghi Jet Androni Giocattoli, a defunct Italian professional cycling team * 3C, the IATA code for defunct American airline RegionsAir * Three-cent piece * 3C (trade association) is an American trade association. In computing: * Three Cs (Compulsory, Capacity, and Conflict), three categories of CPU cache misses * 3C, or Computer Control Company, Inc., a pioneering minicomputer company (1953–1966) * Agile model: 3C (Card, Conversation, Confirmation) * 3C, an abbreviation often used in Taiwan for "computer, communication, and consumer electronics" In genetics: * Alpha-tubulin 3C, a human gene * 3C, or Chromosome conformation capture, a technique used in molecular biology Substituted amphetamines (2C family an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
