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Large Aperture Experiment To Detect The Dark Ages
The Large-Aperture Experiment to Detect the Dark Ages (LEDA) is designed to detect the spectrum of the 21 cm Hydrogen line from the Intergalactic Medium (IGM) at redshifts of 15-30, when the Universe was just ~1% of its present age. It is located at the Long Wavelength Array site, adjacent to the Very Large Array. LEDA principally comprises a "large-N" array correlator (512 inputs over ~ 60 MHz), calibration & imaging system, and instrumentation for measurement of calibrated total-power. These systems will use the station 1 of the Long Wavelength Array as an aperture. LEDA is one of several efforts seeking to study cosmological reionization and the preceding Dark Ages. Others include the Precision Array for Probing the Epoch of Reionization (PAPER), Low Frequency Array (LOFAR), Murchison Widefield Array (MWA), and Giant Metrewave Radio Telescope The Giant Metrewave Radio Telescope (GMRT), located near Pune, Junnar, near Narayangaon at khodad in India, is an array of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Intergalactic Medium
Intergalactic may refer to: * "Intergalactic" (song), a song by the Beastie Boys * ''Intergalactic'' (TV series), a 2021 UK science fiction TV series * Intergalactic space * Intergalactic travel, travel between galaxies in science fiction and speculation See also * * Interstellar (other) *Interplanetary (other) Interplanetary may refer to: *Interplanetary space, the space between the planets of the Solar System *Interplanetary spaceflight, travel between planets *The interplanetary medium, the material that exists in interplanetary space *The InterPlanet ... * Entergalactic (other) {{disambiguation ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Long Wavelength Array
The Long Wavelength Array (LWA) is a radio telescope in central New Mexico. It began preliminary tests of the hardware in 2011, and began regular operations in late 2015. It is one of the few observatories to utilize relatively low frequencies (10-88 MHz), and is used to study relativistic particles, cosmic evolution, astrophysical plasma, decametric radio emissions from Jupiter-like extrasolar planets, and giant flares from magnetars. it consisted of a single station with 256 antennas. The longer term objective of the project is to build 53 stations in total, with a total of 13,000 dipole antennas strategically placed in an area nearly in diameter, to scan the sky at HF and VHF frequencies. Each antenna stands about high and about across the base. The first station, located adjacent to the NRAO's VLA, consists of 256 antennas and was completed in December 2009. It was dedicated in April 2010, and routine operations began in 2011. The second station (LWA2) was u ... [...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 knowledg ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Reionization
In the fields of Big Bang theory and cosmology, reionization is the process that caused matter in the universe to reionize after the lapse of the " dark ages". Reionization is the second of two major phase transitions of gas in the universe (the first is recombination). While the majority of baryonic matter in the universe is in the form of hydrogen and helium, reionization usually refers strictly to the reionization of hydrogen, the element. It is believed that the primordial helium also experienced the same phase of reionization changes, but at different points in the history of the universe. This is usually referred to as helium reionization. Background The first phase change of hydrogen in the universe was recombination, which occurred at a redshift ''z'' = 1089 (379,000 years after the Big Bang), due to the cooling of the universe to the point where the rate of recombination of electrons and protons to form neutral hydrogen was higher than the reionizatio ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dark Ages (cosmology)
The chronology of the universe describes the history and future of the universe according to Big Bang cosmology. Research published in 2015 estimates the earliest stages of the universe's existence as taking place 13.8 billion years ago, with an uncertainty of around 21 million years at the 68% confidence level. The Planck Collaboration in 2015 published the estimate of 13.799 ± 0.021 billion years ago (68% confidence interval). See PDF: page 32, Table 4, Age/Gyr, last column. Outline Chronology in five stages For the purposes of this summary, it is convenient to divide the chronology of the universe since it originated, into five parts. It is generally considered meaningless or unclear whether time existed before this chronology: The very early universe The first picosecond (10−12) of cosmic time. It includes the Planck epoch, during which currently established laws of physics may not apply; the emergence in stages of the four known fundamental interactions or ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Precision Array For Probing The Epoch Of Reionization
The Donald C. Backer Precision Array for Probing the Epoch of Reionization (PAPER) is a radio interferometer funded by the National Science Foundation to detect 21 cm hydrogen (HI) fluctuations occurring when the first galaxies ionized intergalactic gas at around 500 Million years after the Big Bang. PAPER is a focused experiment aimed toward making the first statistical detection of the 21 cm reionization signal. Given the stringent dynamic range requirements for detecting reionization in the face of foregrounds that are five orders of magnitude brighter, the PAPER project is taking a carefully staged engineering approach, optimizing each component in the array to mitigate, at the outset, any potentially debilitating problems in subsequent data calibration and analysis. This staged approach addresses the observational challenges that arise from very-wide-field, high-dynamic-range imaging over wide bandwidths in the presence of transient terrestrial interference. PAP ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Low-Frequency Array (LOFAR)
The Low-Frequency Array, or LOFAR, is a large radio telescope, with an antenna network located mainly in the Netherlands, and spreading across 7 other European countries as of 2019. Originally designed and built by ASTRON, the Netherlands Institute for Radio Astronomy, it was first opened by queen Beatrix of The Netherlands in 2010, and has since been operated on behalf of the International LOFAR Telescope (ILT) partnership by ASTRON. LOFAR consists of a vast array of omnidirectional radio antennas using a modern concept, in which the signals from the separate antennas are not connected directly electrically to act as a single large antenna, as they are in most array antennas. Instead, the LOFAR dipole antennas (of two types) are distributed in stations, within which the antenna signals can be partly combined in analogue electronics, then digitised, then combined again across the full station. This step-wise approach provides great flexibility in setting and rapidly changing the d ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Murchison Widefield Array
The Murchison Widefield Array (MWA) is a joint project between an international consortium of organisations to construct and operate a low-frequency radio array. 'Widefield' refers to its very large field of view (on the order of 30 degrees across). Operating in the frequency range 70–300 MHz, the main scientific goals of the MWA are to detect neutral atomic Hydrogen emission from the cosmological Epoch of Reionization (EoR), to study the sun, the heliosphere, the Earth's ionosphere, and radio transient phenomena, as well as map the extragalactic radio sky. It is located at the Murchison Radio-astronomy Observatory (MRO). Along with the Australian Square Kilometre Array Pathfinder (ASKAP), also at the MRO, and two radio telescopes in South Africa, the Hydrogen Epoch of Reionization Array (HERA) and MeerKAT, the MWA is one of four precursors to the international project known as the Square Kilometre Array (SKA). Development The MWA was to be situated at Mileura S ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Giant Metrewave Radio Telescope
The Giant Metrewave Radio Telescope (GMRT), located near Pune, Junnar, near Narayangaon at khodad in India, is an array of thirty fully steerable parabolic radio telescopes of 45 metre diameter, observing at metre wavelengths. It is operated by the National Centre for Radio Astrophysics (NCRA), a part of the Tata Institute of Fundamental Research, Mumbai. It was conceived and built under the direction of Late Prof. Govind Swarup during 1984 to 1996. It is an interferometric array with baselines of up to . It was recently upgraded with new receivers, after which it is also known as the Upgraded Giant Metrewave Radio Telescope (uGMRT). Location The GMRT Observatory is located about 80 km north of Pune at Khodad. A nearby town is Narayangaon which is around 9 km from the telescope site. The office of NCRA is located in the Savitribai Phule Pune University campus. Science and observations One of the aims for the telescope during its development was to search for the highly ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
National Science Foundation
The National Science Foundation (NSF) is an independent agency of the United States government that supports fundamental research and education in all the non-medical fields of science and engineering. Its medical counterpart is the National Institutes of Health. With an annual budget of about $8.3 billion (fiscal year 2020), the NSF funds approximately 25% of all federally supported basic research conducted by the United States' colleges and universities. In some fields, such as mathematics, computer science, economics, and the social sciences, the NSF is the major source of federal backing. The NSF's director and deputy director are appointed by the President of the United States and confirmed by the United States Senate, whereas the 24 president-appointed members of the National Science Board (NSB) do not require Senate confirmation. The director and deputy director are responsible for administration, planning, budgeting and day-to-day operations of the foundation, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Experiment To Detect The Global EoR Signature
The Experiment to Detect the Global EoR Signature (EDGES) is an experiment and radio telescope located in a radio quiet zone at the Murchison Radio-astronomy Observatory in Western Australia. It is a collaboration between Arizona State University and Haystack Observatory, with infrastructure provided by CSIRO. EoR stands for epoch of reionization, a time in cosmic history when neutral atomic hydrogen gas became ionised due to ultraviolet light from the first stars. Low-band instruments The experiment has two low-band instruments, each of which has a dipole antenna pointed to the zenith and observing a single polarisation. The antenna is around in size, sat on a ground shield. It is coupled with a radio receiver, with a 100m cable run to a digital spectrometer. The instruments operate at , and are separated by 150m. Observations started in August 2015. 78 MHz absorption profile In March 2018 the collaboration published a paper in ''Nature'' announcing the discovery of a bro ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
