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Galaxy H-Alpha Fabry-Perot System
The Galaxy Hα Fabry-Perot System for WHT (GHaFaS) is an astronomical instrument installed on the 4.2 metre William Herschel Telescope (WHT) at Roque de los Muchachos Observatory on the Canary island of La Palma. First light was on 6 July 2007. Its name is a play on the acronym: Galaxy Hα Fabry-Perot System and the Spanish word "''gafas''" meaning spectacles. It produces maps, in intensity and velocity, of extended objects in the sky (which could be external galaxies, star forming regions in the Galaxy, planetary nebulae, or supernova remnants A supernova remnant (SNR) is the structure resulting from the explosion of a star in a supernova. The supernova remnant is bounded by an expanding shock wave, and consists of ejected material expanding from the explosion, and the interstellar ma ..., as examples), which radiate in the H-alpha line, emitted by ionized hydrogen in interstellar space. It can also be used for a variety of other lines. The possibility to detect the emissio ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
William Herschel Telescope
The William Herschel Telescope (WHT) is a optical/near-infrared reflecting telescope located at the Roque de los Muchachos Observatory on the island of La Palma in the Canary Islands, Spain. The telescope, which is named after William Herschel, the discoverer of the planet Uranus, is part of the Isaac Newton Group of Telescopes. It is funded by research councils from the United Kingdom, the Netherlands and Spain. At the time of construction in 1987, the WHT was the third largest single optical telescope in the world.The BTA-6 (6.0 m) and Hale telescope (5.1 m) were both larger; the Multiple Mirror Telescope also had a larger collecting area but did not have a single primary mirror It is currently the second largest in Europe,The neighbouring Gran Telescopio Canarias (10.4 m) overtook the WHT in 2009 to become the largest in Europe and was the last telescope constructed by Grubb Parsons in their 150-year history. The WHT is equipped with a wide range of instrum ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Very Large Array
The Karl G. Jansky Very Large Array (VLA) is a centimeter-wavelength radio astronomy observatory located in central New Mexico on the Plains of San Agustin, between the towns of Magdalena and Datil, ~ west of Socorro. The VLA comprises twenty-eight 25-meter radio telescopes (twenty-seven of which are operational while one is always rotating through maintenance) deployed in a Y-shaped array and all the equipment, instrumentation, and computing power to function as an interferometer. Each of the massive telescopes is mounted on double parallel railroad tracks, so the radius and density of the array can be transformed to adjust the balance between its angular resolution and its surface brightness sensitivity. Astronomers using the VLA have made key observations of black holes and protoplanetary disks around young stars, discovered magnetic filaments and traced complex gas motions at the Milky Way's center, probed the Universe's cosmological parameters, and provided new knowledge ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Astrophysics
Astrophysics is a science that employs the methods and principles of physics and chemistry in the study of astronomical objects and phenomena. As one of the founders of the discipline said, Astrophysics "seeks to ascertain the nature of the heavenly bodies, rather than their positions or motions in space–''what'' they are, rather than ''where'' they are." Among the subjects studied are the Sun, other stars, galaxies, extrasolar planets, the interstellar medium and the cosmic microwave background. Emissions from these objects are examined across all parts of the electromagnetic spectrum, and the properties examined include luminosity, density, temperature, and chemical composition. Because astrophysics is a very broad subject, ''astrophysicists'' apply concepts and methods from many disciplines of physics, including classical mechanics, electromagnetism, statistical mechanics, thermodynamics, quantum mechanics, relativity, nuclear and particle physics, and atomic a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Isaac Newton Group
The Isaac Newton Group of Telescopes or ING consists of three optical telescopes: the William Herschel Telescope, the Isaac Newton Telescope, and the Jacobus Kapteyn Telescope, operated by a collaboration between the UK Science and Technology Facilities Council, the Dutch NWO and the Spanish IAC. The telescopes are located at Roque de los Muchachos Observatory on La Palma in the Canary Islands. These telescopes were formerly under the control of the Royal Greenwich Observatory before UK government cutbacks in 1998. See also * Isaac Newton Sir Isaac Newton (25 December 1642 – 20 March 1726/27) was an English mathematician, physicist, astronomer, alchemist, theologian, and author (described in his time as a " natural philosopher"), widely recognised as one of the g ... External linksING Homepage [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
OB Association
In astronomy, stellar kinematics is the observational study or measurement of the kinematics or motions of stars through space. Stellar kinematics encompasses the measurement of stellar velocities in the Milky Way and its satellites as well as the internal kinematics of more distant galaxies. Measurement of the kinematics of stars in different subcomponents of the Milky Way including the thin disk, the thick disk, the bulge, and the stellar halo provides important information about the formation and evolutionary history of our Galaxy. Kinematic measurements can also identify exotic phenomena such as hypervelocity stars escaping from the Milky Way, which are interpreted as the result of gravitational encounters of binary stars with the supermassive black hole at the Galactic Center. Stellar kinematics is related to but distinct from the subject of stellar dynamics, which involves the theoretical study or modeling of the motions of stars under the influence of gravity. Ste ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Superbubble
A superbubble or supershell is a cavity which is hundreds of light years across and is populated with hot (106 K) gas atoms, less dense than the surrounding interstellar medium, blown against that medium and carved out by multiple supernovae and stellar winds. The winds, passage and gravity of newly born stars strip superbubbles of any other dust or gas. The Solar System lies near the center of an old superbubble, known as the Local Bubble, whose boundaries can be traced by a sudden rise in dust extinction of exterior stars at distances greater than a few hundred light years. Formation The most massive stars, with masses ranging from eight to roughly one hundred solar masses and spectral types of O and early B, are usually found in groups called OB associations. Massive O stars have strong stellar winds, and most of these stars explode as supernovae at the end of their lives. The strongest stellar winds release kinetic energy of 1051 ergs (1044 J) over the lifetime ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Corotation Circle
The corotation circle is the circle around the galactic center of a spiral galaxy, where the stars move at the same speed as the spiral arms. The radius of this circle is called the corotation radius. Inside the circle the stars move faster and outside they move slower than the spiral arms. The Sun is located near the corotation circle of the Milky Way. Influence of dark matter The corotation circle can be used to probe dark matter in a galaxy. In barred spiral galaxies, such as the Milky Way, the stars in the bar rotate faster than the stars in the spiral arms, as they are closer to the centre of the galaxy. Calculations have shown that sufficiently massive dark matter haloes According to modern models of physical cosmology, a dark matter halo is a basic unit of cosmological structure. It is a hypothetical region that has decoupled from cosmic expansion and contains gravitationally bound matter. A single dark mat ... slow the rotation, causing the corotation radius to b ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Redshift
In physics, a redshift is an increase in the wavelength, and corresponding decrease in the frequency and photon energy, of electromagnetic radiation (such as light). The opposite change, a decrease in wavelength and simultaneous increase in frequency and energy, is known as a negative redshift, or blueshift. The terms derive from the colours red and blue which form the extremes of the visible light spectrum. In astronomy and cosmology, the three main causes of electromagnetic redshift are # The radiation travels between objects which are moving apart (" relativistic" redshift, an example of the relativistic Doppler effect) #The radiation travels towards an object in a weaker gravitational potential, i.e. towards an object in less strongly curved (flatter) spacetime ( gravitational redshift) #The radiation travels through expanding space ( cosmological redshift). The observation that all sufficiently distant light sources show redshift corresponding to their distance fr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Atacama Large Millimeter Array
The Atacama Large Millimeter/submillimeter Array (ALMA) is an astronomical interferometer of 66 radio telescopes in the Atacama Desert of northern Chile, which observe electromagnetic radiation at millimeter and submillimeter wavelengths. The array has been constructed on the elevation Chajnantor plateau - near the Llano de Chajnantor Observatory and the Atacama Pathfinder Experiment. This location was chosen for its high elevation and low humidity, factors which are crucial to reduce noise and decrease signal attenuation due to Earth's atmosphere. ALMA provides insight on star birth during the early Stelliferous era and detailed imaging of local star and planet formation. ALMA is an international partnership amongst Europe, the United States, Canada, Japan, South Korea, Taiwan, and Chile. Costing about US$1.4 billion, it is the most expensive ground-based telescope in operation. ALMA began scientific observations in the second half of 2011 and the first imag ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Arcminutes
A minute of arc, arcminute (arcmin), arc minute, or minute arc, denoted by the symbol , is a unit of angular measurement equal to of one degree. Since one degree is of a turn (or complete rotation), one minute of arc 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 circumference is very near . A minute of arc is of a radian. A second of arc, arcsecond (arcsec), or arc second, denoted by the symbol , is of an arcminute, of a degree, of a turn, and (about ) of a radian. These units originated in Babylonian astronomy as sexagesimal 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 milliarcsecond (mas) and microarcsecond (μas), for instance, are commonly used in astrono ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Radio Telescope
A radio telescope is a specialized 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 emitted by astronomical objects, just as optical telescopes are the main observing instrument used in traditional optical astronomy which studies the light wave portion of the spectrum coming from astronomical objects. 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 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 ("dish") antennas similar to those employed in trackin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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