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Porphyrion (radio Galaxy)
Porphyrion is a Fanaroff–Riley class II radio galaxy located 7.5 billion light years away from Earth, with host galaxy J152932.16+601534.4. It is located in the constellation Draco and it was discovered in Low-Frequency Array (LOFAR) data by an international team led by Martijn Oei. Porphyrion has the longest jets of any radio galaxy identified, with lobed structures spanning across, making it the largest known structure of galactic origin. It superseded Alcyoneus, discovered by the same team in 2022, with lobed structures of . Discovery Porphyrion was first reported in a paper in ''Nature'' by Martijn Oei (Leiden University/Caltech) and colleagues, which featured on the cover of the 19 September 2024 issue, after obtaining results from the Low Frequency Array (LOFAR) Two-metre Sky Survey (LoTSS), an interferometric radio survey of the Northern Sky. Porphyrion was part of a large number of new giant radio galaxies discovered by this team. The giant black hole jet system was n ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Draco (constellation)
Draco is a constellation in the far northern sky. Its name is Latin for dragon. It was one of the 48 Lists of constellations, constellations listed by the 2nd century Greek astronomer Ptolemy, and remains one of the 88 modern constellations today. The north pole of the ecliptic is in Draco. Draco is circumpolar star, circumpolar from northern latitudes, meaning that it never sets and can be seen at any time of year. Features Stars Thuban (α Draconis) was the northern pole star from 3942 BC, when it moved farther north than Theta Boötis, until 1793 BC. The Egyptian Pyramids were designed to have one side facing north, with an entrance passage geometrically aligned so that Thuban would be visible at night. Due to the effects of Axial precession (astronomy), precession, it will again be the pole star around the year AD 21000. It is a blue-white giant star of magnitude 3.7, 309 light-years from Earth. The traditional name of Alpha Draconis, Thuban, means "head of the serpe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Giant Metrewave Radio Telescope
The Giant Metrewave Radio Telescope (GMRT), located near Narayangaon, Pune in India, is an array of thirty fully steerable parabolic radio telescopes of 45 metre diameter, observing at metre wavelengths. It is the largest and most sensitive radio telescope array in the world at low frequencies. It is operated by the National Centre for Radio Astrophysics (NCRA), a part of the Tata Institute of Fundamental Research, Mumbai. It was conceived and built under the direction of Govind Swarup during 1984 to 1996. It is an interferometric array with baselines of up to . It was recently upgraded with new receivers, after which it is also known as the upgraded Giant Metrewave Radio Telescope (uGMRT). Location The Giant Metrewave Radio Telescope (GMRT) Observatory is located about 80 km north of Pune at Khodad. A nearby town is Narayangaon which is around 9 km from the telescope site. The office of National Centre for Radio Astrophysics (NCRA) is located in the Savitribai Phul ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Active Galaxies
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] |
Radio Galaxies
A radio galaxy is a galaxy with giant regions of radio emission extending well beyond its visible structure. These energetic radio lobes are powered by jets from its active galactic nucleus. They have luminosities up to 1039 watt, W at radio waves, radio wavelengths between 10 MHz and 100 GHz. The radio emission is due to the synchrotron radiation, synchrotron process. The observed structure in radio emission is determined by the interaction between twin relativistic jet, jets and the external medium, modified by the effects of relativistic beaming. The host galaxy, host galaxies are almost exclusively large elliptical galaxy, elliptical galaxies. ''Radio-loud'' active galaxies can be detected at large distances, making them valuable tools for observational cosmology. Recently, much work has been done on the effects of these objects on the intergalactic medium, particularly in galaxy groups and clusters. The term "radio galaxy" is often used to refer to the entire j ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
List Of Galaxies
There are an estimated 100 billion galaxies in all of the observable universe. On the order of 100,000 galaxies make up the Virgo Supercluster, Local Supercluster, and about 51 galaxies are in the Local Group (see list of nearest galaxies for a complete list). The first attempts at systematic catalogues of galaxies were made in the 1960s, with the Catalogue of Galaxies and Clusters of Galaxies listing 29,418 galaxies and galaxy clusters, and with the Morphological Catalogue of Galaxies, a putatively complete list of galaxies with photographic magnitude above 15, listing 30,642. In the 1980s, the Lyons Groups of Galaxies listed 485 galaxy groups with 3,933 member galaxies. Galaxy Zoo is a project aiming at a more comprehensive list: launched in July 2007, it has classified over one million galaxy images from The Sloan Digital Sky Survey, The Hubble Space Telescope and the Cosmic Assembly Near-Infrared Deep Extragalactic Legacy Survey. __TOC__ Named galaxies This is a list of g ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
List Of Largest Galaxies
This is a list of largest galaxies known, sorted by order of increasing major axis diameters. The unit of measurement used is the light-year (approximately 9.46 kilometers). Overview Galaxies are vast collections of stars, planets, nebulae and other objects that are surrounded by an interstellar medium and held together by gravity. They do not have a definite boundary by nature, and are characterized with gradually decreasing stellar density as a function of increasing distance from its center. Because of this, measuring the sizes of galaxies can often be difficult and have a wide range of results depending on the sensitivity of the detection equipment and the methodology being used. Some galaxies emit more strongly in wavelengths outside the visible spectrum, depending on its stellar population, whose stars may emit more strongly in other wavelengths that are beyond the detection range. It is also important to consider the morphology of the galaxy when attempting to measure i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Newsweek
''Newsweek'' is an American weekly news magazine based in New York City. Founded as a weekly print magazine in 1933, it was widely distributed during the 20th century and has had many notable editors-in-chief. It is currently co-owned by Dev Pragad, the president and chief executive officer (CEO), and Johnathan Davis, who sits on the board; each owns 50% of the company. In August 2010, revenue decline prompted Graham Holdings, the Washington Post Company to sell ''Newsweek'' to the audio pioneer Sidney Harman for one US dollar and an assumption of the magazine's liabilities. Later that year, ''Newsweek'' merged with the news and opinion website ''The Daily Beast'', forming The Newsweek Daily Beast Company, later called ''NewsBeast''. ''Newsweek'' was jointly owned by the estate of Harman and the company IAC (company), IAC. ''Newsweek'' continued to experience financial difficulties, leading to the suspension of print publication at the end of 2012. In 2013, IBT Media acquired ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
The Guardian
''The Guardian'' is a British daily newspaper. It was founded in Manchester in 1821 as ''The Manchester Guardian'' and changed its name in 1959, followed by a move to London. Along with its sister paper, ''The Guardian Weekly'', ''The Guardian'' is part of the Guardian Media Group, owned by the Scott Trust Limited. The trust was created in 1936 to "secure the financial and editorial independence of ''The Guardian'' in perpetuity and to safeguard the journalistic freedom and liberal values of ''The Guardian'' free from commercial or political interference". The trust was converted into a limited company in 2008, with a constitution written so as to maintain for ''The Guardian'' the same protections as were built into the structure of the Scott Trust by its creators. Profits are reinvested in its journalism rather than distributed to owners or shareholders. It is considered a newspaper of record in the UK. The editor-in-chief Katharine Viner succeeded Alan Rusbridger in 2015. S ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hawaii (island)
Hawaii is the List of islands of the United States by area, largest island in the United States, located in the Hawaii, state of Hawaii, the southernmost state in the union. It is the southeasternmost of the Hawaiian Islands, a chain of volcanic islands in the Pacific Ocean, North Pacific Ocean. With an area of , it has 63% of the Hawaiian archipelago's combined landmass. However, it has only 13% of the archipelago's population. The island of Hawaii is the third largest island in Polynesia, behind the North Island, North and South Islands of New Zealand. The island is often referred to as the Island of Hawaii or Hawaii Island to distinguish it from the state. It is also referred to as The Big Island, due to its size relative to the other islands. In Hawaiian language, Hawaiian, the island is sometimes called ''Moku o Keawe''. The word ''keawe'' has several meanings. One definition, "southern cross", is said to be the name of an ancient chief. Another definition is "the bearer". ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
