|
Carl Seyfert
Carl Keenan Seyfert (February 11, 1911 – June 13, 1960) was an American astronomer. He is best known for his 1943 research paper on high-excitation line emission from the centers of some spiral galaxies, which are named Seyfert galaxies after him. Seyfert's Sextet, a group of galaxies, is also named after him. Biography Seyfert was born and raised in Cleveland, Ohio, then attended Harvard University, starting in 1929. He earned his B.S. and M.S. degrees in 1933, and his Ph.D. in astronomy in 1936. His thesis was "Studies of the External Galaxies", supervised by Harlow Shapley. The thesis dealt with colors and magnitudes of galaxies. In 1935 Seyfert married astronomer Muriel Elizabeth Mussels, who was a former Harvard computer who made contributions to the study of ring nebulae. They had two children, daughter Gail Carol and son Carl Keenan Seyfert, Jr. In 1936 Seyfert joined the staff of the new McDonald Observatory in Texas, where he helped get the observatory started. He ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cleveland
Cleveland is a city in the U.S. state of Ohio and the county seat of Cuyahoga County. Located along the southern shore of Lake Erie, it is situated across the Canada–U.S. maritime border and approximately west of the Ohio-Pennsylvania state border. Cleveland is the most populous city on Lake Erie, the second-most populous city in Ohio, and the 53rd-most populous city in the U.S. with a population of 372,624 in 2020. The city anchors the Cleveland metropolitan area, the 33rd-largest in the U.S. at 2.18 million residents, as well as the larger Cleveland– Akron– Canton combined statistical area with 3.63 million residents. Cleveland was founded in 1796 near the mouth of the Cuyahoga River as part of the Connecticut Western Reserve in modern-day Northeast Ohio by General Moses Cleaveland, after whom the city was named. The city's location on the river and the lake shore allowed it to grow into a major commercial and industrial metropolis by the late 19th century, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Case Institute Of Technology
Case Western Reserve University (CWRU) is a Private university, private research university in Cleveland, Ohio, United States. It was established in 1967 by a merger between Western Reserve University and the Case Institute of Technology. Case Western Reserve University comprises eight schools that offer more than 100 undergraduate programs and about 160 graduate and professional options across fields in STEM, medicine, arts, and the humanities. In 2024, the university enrolled 12,475 students (6,528 undergraduate plus 5,947 graduate and professional) from all 50 states and 106 countries and employed more than 1,182 full-time faculty members. The university's athletic teams, Case Western Reserve Spartans, play in NCAA Division III as a founding member of the University Athletic Association. Case Western Reserve University is a member of the Association of American Universities and is Carnegie Classification of Institutions of Higher Education, classified among "R1: Doctoral Univ ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Quarterly Journal Of The Royal Astronomical Society
''Astronomy & Geophysics'' (''A&G'') is a scientific journal and trade magazine published on behalf of the Royal Astronomical Society (RAS) by Oxford University Press. It is distributed bimonthly to members of the RAS. A&G publishes content of interest to professional astronomers and geophysicists, including: news reports, interviews, topical reviews, historical investigations, obituaries, meeting reports and updates on the activities of the RAS. Full-length articles are peer-reviewed, but A&G does not publish original research papers. A&G was established in 1997 as a glossy magazine replacement for the ''Quarterly Journal of the Royal Astronomical Society'' (QJRAS; 1960–1996); it continues the same volume numbering from QJRAS. The editor is Sue Bowler of the University of Leeds. Scope The journal covers astronomy, astrophysics, cosmology, planetary science, solar-terrestrial physics, global and regional geophysics, and the history of these subjects. It also publishes them ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Biographical Encyclopedia Of Astronomers
The ''Biographical Encyclopedia of Astronomers'' (''BEA'') is a two-volume biographical dictionary, first published in 2007, with a second edition released in 2014. The work covers astronomers from all geographies, born from antiquity to mid-1918. It includes more than 1500 biographies of both well-known and more obscure astronomers, produced by 410 contributors. The encyclopedia has been published in both a print and online format by the publisher, Springer. Editions * References External links Publisher's webpage(1st Edition) Publisher's webpage(2nd Edition) Astronomers An astronomer is a scientist in the field of astronomy who focuses on a specific question or field outside the scope of Earth. Astronomers observe astronomical objects, such as stars, planets, moons, comets and galaxies – in either observ ... Historiography of science 21st-century encyclopedias 2007 non-fiction books {{science-hist-book-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Active Galactic Nucleus
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 waves, radio, microwave, infrared, visible spectrum, 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 (astrophysics), 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 cosmology, models of the cosmos. The observed characteristics of an AGN depend on several properties s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Seyfert (crater)
Seyfert is a prominent lunar impact crater that is located on the far side of the Moon. It lies behind the eastern limb of the Moon, to the east of the crater Espin. Just to the north of Seyfert is the crater Harriot and equally close to the south is Polzunov. The outer rim of this crater is slightly elongated to the north, and the northeastern rim is overlain by the satellite crater Seyfert A. This overlapping impact crater has a central ridge on its interior floor. There is a low ridge near the midpoint of Seyfert, but it is less prominent. The inner wall of Seyfert is wider along the northern edge, west of Seyfert A. Several small craters lie along the rim and interior of Seyfert, including a merged group of small craters along the eastern inner wall, a small crater intruding into the southeastern rim, and a pair of small craters along the southern rim of Seyfert A. The interior floor of Seyfert is relatively level, and is marked by a number of tiny craterlets. Traces of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
NGC 6027
NGC 6027 is a lenticular galaxy which is the brightest member of Seyfert's Sextet, a compact group of galaxies. It was discovered by French astronomer Édouard Stephan on 20 March 1882. See also * NGC 6027a * NGC 6027b * NGC 6027c * NGC 6027d * NGC 6027e * Seyfert's Sextet * List of NGC objects (6001–7000) This is a list of NGC objects 6001–7000 from the New General Catalogue (NGC). The astronomical catalogue is composed mainly of star clusters, nebulae, and galaxies. Other objects in the catalogue can be found in the other subpages of the list of ... References External links * * Lenticular galaxies 10116 NED01 056575 +04-38-008 6027 Serpens Astronomical objects discovered in 1882 Discoveries by Édouard Stephan {{lenticular-galaxy-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Jason John Nassau
Jason John Nassau (1893–1965) was an American astronomer. He performed his doctoral studies at Syracuse, and gained his Ph.D. mathematics in 1920. (His thesis was ''Some Theorems in Alternants''.) He then became an assistant professor at the Case Institute of Technology in 1921, teaching astronomy. He continued to instruct at that institution, becoming the university's first chair of astronomy from 1924 until 1959 and chairman of the graduate division from 1936 until 1940. After 1959 he was professor emeritus. From 1924 until 1959 he was also the director of the Case Western Reserve University (CWRU) Warner and Swasey Observatory in Cleveland, Ohio. He was a pioneer in the study of galactic structure. He also discovered a new star cluster, co-discovered 2 novae in 1961, and developed a technique of studying the distribution of red (M-class or cooler) stars. In 1922, Nassau led the formation of the Cleveland Astronomical Society, "a club among those citizens of Cleveland ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Seyfert Galaxies
Seyfert galaxies are one of the two largest groups of active galactic nucleus, active galaxies, along with quasar host galaxies. They have quasar-like Active galactic nucleus, nuclei (very luminous sources of electromagnetic radiation that are outside of our own galaxy) with very high surface brightnesses whose spectrum, spectra reveal strong, high-ionisation emission lines, but unlike quasars, their host galaxies are clearly detectable. Seyfert galaxies account for about 10% of all galaxies and are some of the most intensely studied objects in astronomy, as they are thought to be powered by the same phenomena that occur in quasars, although they are closer and less luminous than quasars. These galaxies have supermassive black holes at their centers which are surrounded by accretion discs of in-falling material. The accretion discs are believed to be the source of the observed ultraviolet radiation. Ultraviolet Spectral line, emission and absorption lines provide the best diagnos ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Messier 77
Messier 77 (M77), also known as NGC 1068 or the Squid Galaxy, is a barred spiral galaxy in the constellation Cetus. It is about away from Earth, and was discovered by Pierre Méchain in 1780, who originally described it as a nebula. Méchain then communicated his discovery to Charles Messier, who subsequently listed the object in his catalog. Both Messier and William Herschel described this galaxy as a star cluster. Today, however, the object is known to be a galaxy. It is one of the brightest Seyfert galaxies visible from Earth and has a D25 isophotal diameter of about . Morphology The morphological classification of NGC 1068 in the De Vaucouleurs system is (R)SA(rs)b, where the '(R)' indicates an outer ring-like structure, 'SA' denotes a non-barred spiral, '(rs)' means a transitional inner ring/spiral structure, and 'b' says the spiral arms are moderately wound. Ann et al. (2015) gave it a class of SAa, suggesting tightly wound arms. However, infrared images of the i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Emission Line
A spectral line is a weaker or stronger region in an otherwise uniform and continuous spectrum. It may result from emission or absorption of light in a narrow frequency range, compared with the nearby frequencies. Spectral lines are often used to identify atoms and molecules. These "fingerprints" can be compared to the previously collected ones of atoms and molecules, and are thus used to identify the atomic and molecular components of stars and planets, which would otherwise be impossible. Types of line spectra Spectral lines are the result of interaction between a quantum system (usually atoms, but sometimes molecules or atomic nuclei) and a single photon. When a photon has about the right amount of energy (which is connected to its frequency) to allow a change in the energy state of the system (in the case of an atom this is usually an electron changing orbitals), the photon is absorbed. Then the energy will be spontaneously re-emitted, either as one photon at the same f ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Reflecting Telescope
A reflecting telescope (also called a reflector) is a telescope that uses a single or a combination of curved mirrors that reflect light and form an image. The reflecting telescope was invented in the 17th century by Isaac Newton as an alternative to the refracting telescope which, at that time, was a design that suffered from severe chromatic aberration. Although reflecting telescopes produce other types of optical aberrations, it is a design that allows for very large diameter Objective (optics), objectives. Almost all of the major telescopes used in astronomy research are reflectors. Many variant forms are in use and some employ extra optical elements to improve image quality or place the image in a mechanically advantageous position. Since reflecting telescopes use mirrors, the design is sometimes referred to as a catoptrics, catoptric telescope. From the time of Newton to the 1800s, the mirror itself was made of metalusually speculum metal. This type included Newton's first ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
