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Yuan-Tseh Lee Array For Microwave Background Anisotropy
The Yuan-Tseh Lee Array for Microwave Background Anisotropy, also known as the Array for Microwave Background Anisotropy (AMiBA), is a radio telescope designed to observe the cosmic microwave background and the Sunyaev-Zel'dovich effect in clusters of galaxies. It is located on Mauna Loa in Hawaii, at above sea level. AMiBA was originally configured as a 7-element interferometer atop a hexapod mount. Observations at a wavelength of 3 mm (86–102 GHz) started in October 2006, and the detections of six clusters by the Sunyaev-Zel'dovich effect were announced in 2008. In 2009 the telescope was upgraded to 13 elements, and it is capable of further expansion to 19 elements. AMiBA is the result of a collaboration between the Academia Sinica Institute of Astronomy and Astrophysics, the National Taiwan University and the Australia Telescope National Facility, and also involves researchers from other universities. After completion of the SZE campaigns, the telescope has ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Radio Telescope
A radio telescope is a specialized antenna (radio), antenna and radio receiver used to detect radio waves from astronomical radio sources in the sky. Radio telescopes are the main observing instrument used in radio astronomy, which studies the radio frequency portion of the electromagnetic spectrum, just as optical telescopes are used to make observations in the visible light, visible portion of the spectrum in traditional optical astronomy. Unlike optical telescopes, radio telescopes can be used in the daytime as well as at night. Since astronomical radio sources such as planets, stars, nebulas and galaxy, galaxies are very far away, the radio waves coming from them are extremely weak, so radio telescopes require very large antennas to collect enough radio energy to study them, and extremely sensitive receiving equipment. Radio telescopes are typically large Parabolic antenna, parabolic ("dish") antennas similar to those employed in tracking and communicating with satellites an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
System Temperature
In electronics, noise temperature is one way of expressing the level of available noise power introduced by a component or source. The power spectral density of the noise is expressed in terms of the temperature (in kelvins) that would produce that level of Johnson–Nyquist noise, thus: :\frac = k_\text T where: * P_\text is the noise power (in W, watts) * B is the total bandwidth (Hz, hertz) over which that noise power is measured * k_\text is the Boltzmann constant (, joules per kelvin) * T is the noise temperature (K, kelvin) Thus the noise temperature is proportional to the power spectral density of the noise, P_\text/ B. That is the power that would be absorbed from the component or source by a matched load. Noise temperature is generally a function of frequency, unlike that of an ideal resistor which is simply equal to the actual temperature of the resistor at all frequencies. Noise voltage and current A noisy component may be modelled as a noiseless component in se ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Abell 2261
Abell 2261 is one of 25 galaxy clusters being studied as part of the Cluster Lensing And Supernova survey with Hubble (CLASH) program, a major project to build a library of scientific data on lensing clusters. It also has the galaxy A2261-BCG (short for Abell 2261 Brightest Cluster Galaxy) which has one of the largest galaxy cores ever observed. In January 2021, astronomers using the Hubble Space Telescope were reported to be unable to locate a supermassive black hole presumed to be at the center of the galaxy. A newer and larger space telescope, the James Webb Space Telescope The James Webb Space Telescope (JWST) is a space telescope designed to conduct infrared astronomy. As the largest telescope in space, it is equipped with high-resolution and high-sensitivity instruments, allowing it to view objects too old, Lis ..., launched in December 2021, may help determine the object's whereabouts, according to the astronomers. References Galaxy clusters Hercules (constellat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Abell 2163
Abell 2163 is one of the richest and most distant of the clusters of galaxies found in the Abell catalogue. Its abell richness class is 2 and position is at a redshift z=0.2. Data from Chandra X-ray Observatory have shown that it is the hottest galaxy cluster in the Abell catalogue. It is also a merging cluster. The galaxy density and mass distribution in the central region of this cluster have also been determined by weak gravitational lensing. These analyses show very similar mass and galaxy distributions, with two coincident maxima and a flat shape elongated in the east-west direction, but the weak lensing signal is surprisingly faint in comparison to what could be expected from the cluster X-ray properties. However, these detailed studies are limited to the inner 8’×8’ region of the cluster, and do not include the peripheral clumps such as A2163-B. La Barbera et al. (2004) estimated the photometric redshifts of galaxies in A2163-B, showing that this structure lies at the t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Abell 2142
Abell 2142, or A2142, is a huge, X-ray luminous galaxy cluster in the constellation Corona Borealis. It is the result of a still ongoing merger between two galaxy clusters. The combined cluster is six million light years across, contains hundreds of galaxies and enough gas to make a thousand more. It is "one of the most massive objects in the universe." X-Ray image The adjacent image was taken 20 August 1999 with the Chandra X-ray Observatory's 0.3-10.0 k eV Advanced CCD Imaging Spectrometer (ACIS), and covers an area of 7.5 x 7.2 arc minutes. It shows a colossal cosmic "weather system" produced by the collision of two giant clusters of galaxies. For the first time, the pressure fronts in the system have been traced in detail, and show a bright, but relatively cool 50 million degree Celsius central region (white) embedded in large elongated cloud of 70 million degree Celsius gas (magenta), all of which is roiling in a faint "atmosphere" of 100 million degree Celsius gas (faint ma ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Abell 1995
{{disambiguation, geo ...
Abell may refer to: People *Abell (surname) * George O. Abell, of the astronomical catalogues fame Places ;United States * Abell, Maryland, a location in St. Mary's County, Maryland * Abell, a neighborhood in Baltimore, Maryland * Abells Corners, Wisconsin, an unincorporated community Astronomy *Abell catalogue of rich clusters of galaxies (ACO) *Abell Catalog of Planetary Nebulae (A) Bibliographical database *ABELL, the ''Annual Bibliography of English Language and Literature'' See also *Abel (other) Abel was a son of Adam and Eve in the Bible. According to the Bible, he was the first person to die, murdered by his brother Cain. Abel may also refer to: People and fictional characters * Abel (given name), including a list of people and ficti ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Abell 1689
Abell 1689 is a galaxy cluster in the constellation Virgo (constellation), Virgo over 2.3 billion light-years away. Details Abell 1689 is one of the biggest and most massive galaxy clusters known and acts as a gravitational lens, distorting the images of galaxies that lie behind it. It has the largest system of gravitational arcs ever found. Abell 1689 shows over 160,000 globular clusters, the largest population ever found. There is evidence of merging and gases in excess of 100 million degrees. The very large mass of this cluster makes it useful for the study of dark matter and gravitational lensing. At the time of its discovery in 2008, one of the lensed galaxies, A1689-zD1, was the most List of the most distant astronomical objects, distant galaxy found. Gallery File:Gravitationell-lins-4.jpg, Yellow galaxies belong to the cluster itself. Red and blue are background galaxies gravitational lens, gravitationally lensed. File:Abell 1689.jpg, Mass map of Abell 1689. File:Glob ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Arcminute
A minute of arc, arcminute (abbreviated as arcmin), arc minute, or minute arc, denoted by the symbol , is a unit of angular measurement equal to of a degree. Since one degree is of a turn, or complete rotation, one arcminute is of a turn. The nautical mile (nmi) was originally defined as the arc length of a minute of latitude on a spherical Earth, so the actual Earth's circumference is very near . A minute of arc is of a radian. A second of arc, arcsecond (abbreviated as arcsec), or arc second, denoted by the symbol , is a unit of angular measurement equal to of a minute of arc, of a degree, of a turn, and (about ) of a radian. These units originated in Babylonian astronomy as sexagesimal (base 60) subdivisions of the degree; they are used in fields that involve very small angles, such as astronomy, optometry, ophthalmology, optics, navigation, land surveying, and marksmanship. To express even smaller angles, standard SI prefixes can be employed; the milliarcse ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Multipole
A multipole expansion is a mathematical series representing a function that depends on angles—usually the two angles used in the spherical coordinate system (the polar and azimuthal angles) for three-dimensional Euclidean space, \R^3. Multipole expansions are useful because, similar to Taylor series, oftentimes only the first few terms are needed to provide a good approximation of the original function. The function being expanded may be real- or complex-valued and is defined either on \R^3, or less often on \R^n for some other Multipole expansions are used frequently in the study of electromagnetic and gravitational fields, where the fields at distant points are given in terms of sources in a small region. The multipole expansion with angles is often combined with an expansion in radius. Such a combination gives an expansion describing a function throughout three-dimensional space. The multipole expansion is expressed as a sum of terms with progressively finer angular featu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Anisotropies
Anisotropy () is the structural property of non-uniformity in different directions, as opposed to isotropy. An anisotropic object or pattern has properties that differ according to direction of measurement. For example, many materials exhibit very different physical or mechanical properties when measured along different axes, e.g. absorbance, refractive index, conductivity, and tensile strength. An example of anisotropy is light coming through a polarizer. Another is wood, which is easier to split along its grain than across it because of the directional non-uniformity of the grain (the grain is the same in one direction, not all directions). Fields of interest Computer graphics In the field of computer graphics, an anisotropic surface changes in appearance as it rotates about its geometric normal, as is the case with velvet. Anisotropic filtering (AF) is a method of enhancing the image quality of textures on surfaces that are far away and viewed at a shallow angle. Older te ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Yuan-Tseh Lee
Yuan Tseh Lee (; born 19 November 1936) is a Taiwanese chemist who was awarded the Nobel Prize in Chemistry in 1986 for his contributions to the development of reaction dynamics. Lee is a professor emeritus at the University of California, Berkeley, and honorary director of the Nagoya University Institute for Advanced Study along with Ryoji Noyori. He was awarded the Nobel with John C. Polanyi and Dudley R. Herschbach for "contributions to the dynamics of chemical elementary processes". He was the first Taiwanese person be awarded the Nobel Prize. His research in physical chemistry concerned the use of advanced chemical kinetics techniques to investigate and manipulate the behavior of chemical reactions using crossed molecular beams. From 1994 to 2006, Lee served as the President of the Academia Sinica. In 2011, he was elected head of the International Council for Science. Early life and education Lee was born to a Hoklo Taiwanese family in Shinchiku City (modern-day Hsinch ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Jupiter
Jupiter is the fifth planet from the Sun and the List of Solar System objects by size, largest in the Solar System. It is a gas giant with a Jupiter mass, mass more than 2.5 times that of all the other planets in the Solar System combined and slightly less than one-thousandth the mass of the Sun. Its diameter is 11 times that of Earth and a tenth that of the Sun. Jupiter orbits the Sun at a distance of , with an orbital period of . It is the List of brightest natural objects in the sky, third-brightest natural object in the Earth's night sky, after the Moon and Venus, and has been observed since prehistoric times. Its name derives from that of Jupiter (god), Jupiter, the chief deity of ancient Roman religion. Jupiter was the first of the Sun's planets to form, and its inward migration during the primordial phase of the Solar System affected much of the formation history of the other planets. Jupiter's atmosphere consists of 76% hydrogen and 24% helium by mass, with a denser ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
