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Cygnus A
Cygnus A ( 3C 405) is a radio galaxy, one of the strongest radio sources in the sky. Discovery and Identification A concentrated radio source in Cygnus was discovered by Grote Reber in 1939. In 1946 Stanley Hey and his colleague James Phillips identified that the source scintillated rapidly, and must therefore be a compact object. In 1951, Cygnus A, along with Cassiopeia A, and Puppis A were the first "radio sources" identified with an optical instrument. Of these, Cygnus A became the first radio galaxy, the other two being nebulae inside the Milky Way. In 1953 Roger Jennison and M K Das Gupta showed it to be a double source. Like all radio galaxies, it contains an active galactic nucleus (AGN). The supermassive black hole at the core has a mass of . Jets from the AGN have also been observed to induce hotspots in the radio lobes and subsequently holes in the surround Intergalactic medium (IGM). Cygnus A is the cD galaxy in a rich galaxy cluster of the same name, and has ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
False-color
False colors and pseudo colors respectively refers to a group of color rendering methods used to display images in colors which were recorded in the visible or non-visible parts of the electromagnetic spectrum. A false-color image is an image that depicts an object in colors that differ from those a photograph (a true-color image) would show. In this image, colors have been assigned to three different wavelengths that human eyes cannot normally see. In addition, variants of ''false colors'' such as pseudocolors, density slicing, and choropleths are used for information visualization of either data gathered by a single grayscale channel or data not depicting parts of the electromagnetic spectrum (e.g. elevation in relief maps or tissue types in magnetic resonance imaging). Types of color renderings True color The concept behind true color can help in understanding false color. An image is called a ''true-color'' image when it offers a natural color rendition, or when i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
DB (astronomical Catalog)
DB, dB or db may refer to: Arts, entertainment and media * ''Daily Bugle'' or ''DB'', a fictional New York City newspaper in Marvel Comics * ''Doing Business Report'', by the World Bank Group * Dragon Ball, a Japanese media franchise Music * D♭ (musical note) * DB Records, Atlanta, Georgia, US * The dB's, an American band in the 1980s * DJ DB, a New York–based British DJ Brands and enterprises * DB (car), a French automobile maker * Brit Air (IATA airline code) * DB Breweries, a New Zealand company * DB Networks, an American information security firm * Deutsche Bahn, a German railway company since 1994 * Deutsche Bank (NYSE symbol), a multinational investment bank headquartered in Frankfurt, Germany * Deutsche Bundesbahn, national railway company of the Federal Republic of Germany, 1949–1994 * Dolderbahn, a rack railway in Zürich, Switzerland Places * Dâmbovița County (ISO 3166-2:RO code), Romania * DB Draw, a bridge over the Passaic River, US * Discovery Bay, a resid ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mrinal Kumar Das Gupta
Mrinal Kumar Das Gupta FNI (1 September 1923 – 28 November 2005, Kolkata) was an Indian astronomer. He was born in erstwhile Barishal district in present-day Bangladesh. He received his B.Sc and M.Sc degrees in Physics from Dhaka University in 1944 and 1945 respectively. Later he joined the department of Radio Physics and Electronics of the University of Calcutta as a researcher. In 1954, he obtained his Ph.D. from the University of Manchester. Later he became the head of the department of the Institute of Radio Physics and Electronics at Calcutta University. Das Gupta worked with Robert Hanbury Brown and Roger Jennison, in building the first intensity interferometers at radio wavelength in the early 1950s and measured the apparent angular structures of two radio sources, Cygnus A and Cassiopeia A. Das Gupta was elected as a ''Fellow of the National Academy of Science'' in 1974 by the Indian National Science Academy, New Delhi and as a ''Fellow of the Academy of Science'' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Roger Clifton Jennison
Roger Clifton Jennison (18 December 1922 – 29 December 2006) worked as a radio astronomer at Jodrell Bank under the guidance of Robert Hanbury Brown. Jennison made a number of discoveries in the field of radio astronomy, including the discovery of the double nature of radio source Cygnus A ( 3C 405.0) with M K Das Gupta and the mapping of Cassiopeia A with V Latham. Early life Jennison was born in Grimsby, England, in 1922. His education was at Clee Grammar School for Boys. He was commissioned from RAF aircrew to the Technical Branch-Signals, where he developed radar and microwave systems using the magnetron. Radio astronomy In the 1950s he developed a new observable for obtaining information about visibility phases in an interferometer when delay errors are present called the closure phase. He performed the first measurements of closure phase at optical wavelengths. Jennison saw greater potential for his technique in radio interferometry, and proposed that it should be te ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Milky Way
The Milky Way or Milky Way Galaxy is the galaxy that includes the Solar System, with the name describing the #Appearance, galaxy's appearance from Earth: a hazy band of light seen in the night sky formed from stars in other arms of the galaxy, which are so far away that they cannot be individually distinguished by the naked eye. The Milky Way is a barred spiral galaxy with a Galaxy#Isophotal diameter, D25 isophotal diameter estimated at , but only about 1,000 light-years thick at the spiral arms (more at the bulge). Recent simulations suggest that a dark matter area, also containing some visible stars, may extend up to a diameter of almost 2 million light-years (613 kpc). The Milky Way has several List of Milky Way's satellite galaxies, satellite galaxies and is part of the Local Group of galaxies, forming part of the Virgo Supercluster which is itself a component of the Laniakea Supercluster. It is estimated to contain 100–400 billion stars and at least that number of pla ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nebula
A nebula (; or nebulas) is a distinct luminescent part of interstellar medium, which can consist of ionized, neutral, or molecular hydrogen and also cosmic dust. Nebulae are often star-forming regions, such as in the Pillars of Creation in the Eagle Nebula. In these regions, the formations of gas, dust, and other materials "clump" together to form denser regions, which attract further matter and eventually become dense enough to form stars. The remaining material is then thought to form planets and other planetary system objects. Most nebulae are of vast size; some are hundreds of light-years in diameter. A nebula that is visible to the human eye from Earth would appear larger, but no brighter, from close by. The Orion Nebula, the brightest nebula in the sky and occupying an area twice the angular diameter of the full Moon, can be viewed with the naked eye but was missed by early astronomers. Although denser than the space surrounding them, most nebulae are far less dens ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Puppis A
Puppis A (Pup A) is a supernova remnant (SNR) about 100 light-years in diameter and roughly 6500–7000 light-years distant. Its apparent angular diameter is about 1 degree. The light of the supernova explosion reached Earth approximately 3700 years ago. Although it overlaps the Vela Supernova Remnant, it is four times more distant. A hypervelocity neutron star known as the Cosmic Cannonball has been found in this SNR. Puppis X-1 Puppis X-1 (Puppis A) was discovered by a Skylark flight in October 1971, viewed for 1 min with an accuracy ≥ 2 arcsec, probably at 1M 0821-426, with Puppis A ( RA 08h 23m 08.16s Dec -42° 41′ 41.40″) as the likely visual counterpart. Puppis A is one of the brightest X-ray sources in the X-ray sky. Its X-ray designation is 2U 0821-42. Gallery Image:Puppis labeled.jpg, wide-field composite view of the supernova remnant Puppis A (X-rays from ROSAT ROSAT (short for Röntgensatellit; in German X-rays are called Röntgenstrahlen, in honour ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cassiopeia A
Cassiopeia A (Cas A) () is a supernova remnant (SNR) in the constellation Cassiopeia and the brightest extrasolar radio source in the sky at frequencies above 1 GHz. The supernova occurred approximately away within the Milky Way; given the width of the Orion Arm, it lies in the next-nearest arm outwards, the Perseus Arm, about 30 degrees from the Galactic anticenter. The expanding cloud of material left over from the supernova now appears approximately across from Earth's perspective. It has been seen in wavelengths of visible light with amateur telescopes down to 234 mm (9.25 in) with filters. It is estimated that light from the supernova itself first reached Earth near the 1660s, although there are no definitively corresponding records from then. Cas A is circumpolar at and above mid-Northern latitudes which had extensive records and basic telescopes. Its likely omission in records is probably due to interstellar dust absorbing optical wavelen ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Twinkling
Twinkling, also called scintillation, is a generic term for variations in apparent brightness, colour, or position of a distant luminous object viewed through a medium.Wang, Ting-I; Williams, Donn"Scintillation technology bests NIST" , ''InTech'', May 1, 2005. If the object lies outside the Earth's atmosphere, as in the case of stars and planets, the phenomenon is termed ''astronomical scintillation''; for objects within the atmosphere, the phenomenon is termed ''terrestrial scintillation''. As one of the three principal factors governing astronomical seeing (the others being light pollution and cloud cover), atmospheric scintillation is defined as variations in illuminance only. In simple terms, twinkling of stars is caused by the passing of light through different layers of a turbulent atmosphere. Most scintillation effects are caused by anomalous atmospheric refraction caused by small-scale fluctuations in air density usually related to temperature gradients. Scintillatio ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
James Stanley Hey
James Stanley Hey (3 May 1909 – 27 February 2000) was an English physicist and radio astronomer. With the targeted application of radar technology for astronomical research, he laid the basis for the development of radio astronomy. While working in Richmond Park during the Second World War, Hey discovered that the Sun radiates radio waves and localised for the first time an extragalactic radio source in the constellation Cygnus. Early life and education He was born in 1909 in Nelson, Lancashire, the third son of a cotton manufacturer, which was the main industry in Lancashire. Hey studied physics at the University of Manchester, graduating in 1930, and obtained his master's degree in X-ray crystallography the next year as a student of Lawrence Bragg. Career After graduating, Hey became a teacher, and taught physics at Burnley Grammar School for some years. In 1940 Hey joined the Air Defence Research and Development Establishment's (ADRDE) Operational Research Group, l ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Grote Reber
Grote Reber (December 22, 1911 – December 20, 2002) was an American pioneer of radio astronomy, which combined his interests in amateur radio and amateur astronomy. He was instrumental in investigating and extending Karl Jansky's pioneering work and conducted the first sky survey in the radio frequencies. His 1937 radio antenna was the second ever to be used for astronomical purposes and the first parabolic reflecting antenna to be used as a radio telescope. For nearly a decade he was the world's only radio astronomer.Wayne Orchiston, The New Astronomy: Opening the Electromagnetic Window and Expanding our View of Planet Earth: A Meeting to Honor Woody Sullivan on his 60th Birthday, Springer Science & Business Media – 2006, p. 63Robert Bless (1996), ''Discovering the Cosmos'', University Science Books, p. 215 Life Reber was born and raised in Wheaton, Illinois, a suburb of Chicago, and graduated from Armour Institute of Technology (now Illinois Institute of Technology) in 19 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Astronomical Radio Source
An astronomical radio source is an object in outer space that emits strong radio waves. Radio emission comes from a wide variety of sources. Such objects are among the most extreme and energetic physical processes in the universe. History In 1932, American physicist and radio engineer Karl Jansky detected radio waves coming from an unknown source in the center of the Milky Way galaxy. Jansky was studying the origins of radio frequency interference for Bell Laboratories. He found "...a steady hiss type static of unknown origin", which eventually he concluded had an extraterrestrial origin. This was the first time that radio waves were detected from outer space. The first radio sky survey was conducted by Grote Reber and was completed in 1941. In the 1970s, some stars in the Milky Way were found to be radio emitters, one of the strongest being the unique binary MWC 349. Sources: Solar System The Sun As the nearest star, the Sun is the brightest radiation source in most frequenc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
