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The Karl G. Jansky Very Large Array (VLA) is a radio astronomy observatory located on the Plains of San Agustin, between the towns of Magdalena and Datil, some 50 miles (80 km) west of Socorro, New Mexico. It comprises 27 25-meter radio telescopes 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 focus on particular bands of wavelength.〔http://www.vla.nrao.edu〕 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 about the physical mechanisms that produce radio emission. The VLA stands at an elevation of 6970 ft (2124 m) above sea level. It is a component of the National Radio Astronomy Observatory (NRAO). U.S. Route 60 passes through the complex, which is adjacent to the Boy Scout Double H High Adventure Base. == Characteristics == The radio telescope comprises 27 independent antennae, each of which has a dish diameter of 25 meters (82 feet) and weighs 209 metric tons (230 Short tons). The antennae are distributed along the three arms of a track, shaped in a wye (or Y) -configuration, (each of which measures 21 km/13 miles long). Using the rail tracks that follow each of these arms—and that, at one point, intersect with U.S. Route 60 at a level crossing—and a specially designed lifting locomotive ("Hein's Trein"), the antennas can be physically relocated to a number of prepared positions, allowing aperture synthesis interferometry with up to 351 independent baselines: in essence, the array acts as a single antenna with a variable diameter. The angular resolution that can be reached is between 0.2 and 0.004 arcseconds.〔https://public.nrao.edu/telescopes/vla/vla-basics〕 There are four commonly used configurations, designated A (the largest) through D (the tightest, when all the dishes are within 600 m of the center point). The observatory normally cycles through all the various possible configurations (including several hybrids) every 16 months; the antennas are moved every three to four months. Moves to smaller configurations are done in two stages, first shortening the east and west arms and later shortening the north arm. This allows for a short period of improved imaging of extremely northerly or southerly sources. The frequency coverage is 74 MHz to 50 GHz (400 to 0.7 cm).〔 The Array Operations Center (AOC) for the VLA is located on the campus of the New Mexico Institute of Mining and Technology in Socorro, New Mexico. The AOC also currently serves as the control center for the Very Long Baseline Array (VLBA), a VLBI array of ten 25-meter dishes located from Hawaii in the west to the U.S. Virgin Islands in the east that constitutes the world's largest dedicated, full-time astronomical instrument. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Karl G. Jansky Very Large Array」の詳細全文を読む スポンサード リンク
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