WorldWideScience

Sample records for radio astronomical arrays

  1. Antenna data storage concept for phased array radio astronomical instruments

    Science.gov (United States)

    Gunst, André W.; Kruithof, Gert H.

    2018-04-01

    Low frequency Radio Astronomy instruments like LOFAR and SKA-LOW use arrays of dipole antennas for the collection of radio signals from the sky. Due to the large number of antennas involved, the total data rate produced by all the antennas is enormous. Storage of the antenna data is both economically and technologically infeasible using the current state of the art storage technology. Therefore, real-time processing of the antenna voltage data using beam forming and correlation is applied to achieve a data reduction throughout the signal chain. However, most science could equally well be performed using an archive of raw antenna voltage data coming straight from the A/D converters instead of capturing and processing the antenna data in real time over and over again. Trends on storage and computing technology make such an approach feasible on a time scale of approximately 10 years. The benefits of such a system approach are more science output and a higher flexibility with respect to the science operations. In this paper we present a radically new system concept for a radio telescope based on storage of raw antenna data. LOFAR is used as an example for such a future instrument.

  2. LONG-TERM CALIBRATION STABILITY OF A RADIO ASTRONOMICAL PHASED ARRAY FEED

    Energy Technology Data Exchange (ETDEWEB)

    Elmer, Michael; Jeffs, Brian D.; Warnick, Karl F. [Department of Electrical and Computer Engineering, Brigham Young University, Provo, UT 84602 (United States)

    2013-01-01

    There are many challenges associated with the implementation of a phased array feed for radio astronomy applications. Among these is the need to have an adequate set of calibration measurements so that reliable beamformers can be computed. Changes in the operating environment and temporal gain drift in the electronics contribute to calibration drift, which affects the beamformer performance. We will show that calibration measurements are relatively stable over a 5 day period and may remain so for up to 70 days or longer. We have incorporated the use of a calibration update system that has the potential to refresh a set of old calibrators, specifically correcting for electronic gain drift. However, the long-term variations that are present with fresh, current calibrators are greater than the degradation due to using an old calibration set, suggesting that, at this time, there is not a need for sophisticated calibration update systems or algorithms.

  3. "Movie Star" Acting Strangely, Radio Astronomers Find

    Science.gov (United States)

    1999-01-01

    Astronomers have used the National Science Foundation's Very Long Baseline Array (VLBA) radio telescope to make the first-ever time-lapse "movie" showing details of gas motions around a star other than our Sun. The study, the largest observational project yet undertaken using Very Long Baseline Interferometry, has produced surprising results that indicate scientists do not fully understand stellar atmospheres. The "movie" shows that the atmosphere of a pulsating star more than 1,000 light-years away continues to expand during a part of the star's pulsation period in which astronomers expected it to start contracting. Philip Diamond and Athol Kemball, of the National Radio Astronomy Observatory (NRAO) in Socorro, New Mexico, announced their findings at the American Astronomical Society's meeting in Austin, TX, today. "The continued expansion we're seeing contradicts current theoretical models for how these stars work," Diamond said. "The models have assumed spherical symmetry in the star's atmosphere, and our movie shows that this is not the case. Such models suggest that a shock wave passes outward from the star. Once it's passed, then the atmosphere should begin to contract because of the star's gravity. We've long passed that point and the contraction has not begun." The time-lapse images show that the gas motions are not uniform around the star. Most of the motion is that of gas moving directly outward from the star's surface. However, in about one-fourth of the ring, there are peculiar motions that do not fit this pattern. The scientists speculate that the rate of mass loss may not be the same from all parts of the star's surface. "A similar star behaved as predicted when studied a few years ago, so we're left to wonder what's different about this one," Diamond said. "Right now, we think that different rates of mass loss in the two stars may be the cause of the difference. This star is losing mass at 100 times the rate of the star in the earlier study." "This

  4. Powerful Radio Burst Indicates New Astronomical Phenomenon

    Science.gov (United States)

    2007-09-01

    Astronomers studying archival data from an Australian radio telescope have discovered a powerful, short-lived burst of radio waves that they say indicates an entirely new type of astronomical phenomenon. Region of Strong Radio Burst Visible-light (negative greyscale) and radio (contours) image of Small Magellanic Cloud and area where burst originated. CREDIT: Lorimer et al., NRAO/AUI/NSF Click on image for high-resolution file ( 114 KB) "This burst appears to have originated from the distant Universe and may have been produced by an exotic event such as the collision of two neutron stars or the death throes of an evaporating black hole," said Duncan Lorimer, Assistant Professor of Physics at West Virginia University (WVU) and the National Radio Astronomy Observatory (NRAO). The research team led by Lorimer consists of Matthew Bailes of Swinburne University in Australia, Maura McLaughlin of WVU and NRAO, David Narkevic of WVU, and Fronefield Crawford of Franklin and Marshall College in Lancaster, Pennsylvania. The astronomers announced their findings in the September 27 issue of the online journal Science Express. The startling discovery came as WVU undergraduate student David Narkevic re-analyzed data from observations of the Small Magellanic Cloud made by the 210-foot Parkes radio telescope in Australia. The data came from a survey of the Magellanic Clouds that included 480 hours of observations. "This survey had sought to discover new pulsars, and the data already had been searched for the type of pulsating signals they produce," Lorimer said. "We re-examined the data, looking for bursts that, unlike the usual ones from pulsars, are not periodic," he added. The survey had covered the Magellanic Clouds, a pair of small galaxies in orbit around our own Milky Way Galaxy. Some 200,000 light-years from Earth, the Magellanic Clouds are prominent features in the Southern sky. Ironically, the new discovery is not part of these galaxies, but rather is much more distant

  5. Astronomers Win Protection for Key Part of Radio Spectrum

    Science.gov (United States)

    2000-06-01

    International Telecommunication Union meet to painstakingly parcel out the radio frequency spectrum between radio-based applications such as personal communications, satellite broadcasting, GPS and amateur radio, and the sciences of radio astronomy, earth exploration and deep space research. The WRC also coordinates sharing between services in the same radio bands. WRC decisions are incorporated into the Radio Regulations that govern radio services worldwide. The new spectrum allocations for radio astronomy are the first since 1979. Millimeter-wave astronomy was then in its infancy and many of its needs were not yet known. As astronomers began to explore this region of the spectrum they found spectral lines from many interesting molecules in space. Many of those lines had not fallen into the areas originally set aside for astronomy, but most will be under the new allocations. "It's a win for millimeter-wave science," said Dr. John Whiteoak of the Australia Telescope National Facility, Australian delegate to WRC-00. "This secures its future." The protection is a significant step for both existing millimeter-wave telescopes and new ones such as the Atacama Large Millimeter Array (ALMA) now being planned by a U.S.-European consortium. Even at its isolated site in Chile's Atacama desert, ALMA would be vulnerable to interference from satellite emissions. Sensitive radio astronomy receivers are blinded by these emissions, just as an optical telescope would be by a searchlight. "There is more energy at millimeter and sub-millimeter wavelengths washing through the Universe than there is of light or any other kind of radiation," said ALMA Project Scientist, Dr. Al Wootten of the National Radio Astronomy Observatory. "Imaging the sources of this energy can tell us a great deal about the formation of stars and galaxies, and even planets." "But the Earth's atmosphere isn't very kind to us - it has only a few windows at these frequencies, and not very transparent ones at that. They are

  6. Astronomers Detect Powerful Bursting Radio Source Discovery Points to New Class of Astronomical Objects

    Science.gov (United States)

    2005-03-01

    Astronomers at Sweet Briar College and the Naval Research Laboratory (NRL) have detected a powerful new bursting radio source whose unique properties suggest the discovery of a new class of astronomical objects. The researchers have monitored the center of the Milky Way Galaxy for several years and reveal their findings in the March 3, 2005 edition of the journal, “Nature”. This radio image of the central region of the Milky Way Galaxy holds a new radio source, GCRT J1745-3009. The arrow points to an expanding ring of debris expelled by a supernova. CREDIT: N.E. Kassim et al., Naval Research Laboratory, NRAO/AUI/NSF Principal investigator, Dr. Scott Hyman, professor of physics at Sweet Briar College, said the discovery came after analyzing some additional observations from 2002 provided by researchers at Northwestern University. “"We hit the jackpot!” Hyman said referring to the observations. “An image of the Galactic center, made by collecting radio waves of about 1-meter in wavelength, revealed multiple bursts from the source during a seven-hour period from Sept. 30 to Oct. 1, 2002 — five bursts in fact, and repeating at remarkably constant intervals.” Hyman, four Sweet Briar students, and his NRL collaborators, Drs. Namir Kassim and Joseph Lazio, happened upon transient emission from two radio sources while studying the Galactic center in 1998. This prompted the team to propose an ongoing monitoring program using the National Science Foundation’s Very Large Array (VLA) radio telescope in New Mexico. The National Radio Astronomy Observatory, which operates the VLA, approved the program. The data collected, laid the groundwork for the detection of the new radio source. “Amazingly, even though the sky is known to be full of transient objects emitting at X- and gamma-ray wavelengths,” NRL astronomer Dr. Joseph Lazio pointed out, “very little has been done to look for radio bursts, which are often easier for astronomical objects to produce

  7. Astronomers Make First Images With Space Radio Telescope

    Science.gov (United States)

    1997-07-01

    Marking an important new milestone in radio astronomy history, scientists at the National Radio Astronomy Observatory (NRAO) in Socorro, New Mexico, have made the first images using a radio telescope antenna in space. The images, more than a million times more detailed than those produced by the human eye, used the new Japanese HALCA satellite, working in conjunction with the National Science Foundation's (NSF) Very Long Baseline Array (VLBA) and Very Large Array (VLA) ground-based radio telescopes. The landmark images are the result of a long-term NRAO effort supported by the National Aeronautics and Space Administration (NASA). "This success means that our ability to make detailed radio images of objects in the universe is no longer limited by the size of the Earth," said NRAO Director Paul Vanden Bout. "Astronomy's vision has just become much sharper." HALCA, launched on Feb. 11 by Japan's Institute of Space and Astronautical Science (ISAS), is the first satellite designed for radio astronomy imaging. It is part of an international collaboration led by ISAS and backed by NRAO; Japan's National Astronomical Observatory; NASA's Jet Propulsion Laboratory (JPL); the Canadian Space Agency; the Australia Telescope National Facility; the European VLBI Network and the Joint Institute for Very Long Baseline Interferometry in Europe. On May 22, HALCA observed a distant active galaxy called PKS 1519-273, while the VLBA and VLA also observed it. Data from the satellite was received by a tracking station at the NRAO facility in Green Bank, West Virginia. Tape-recorded data from the satellite and from the radio telescopes on the ground were sent to NRAO's Array Operations Center (AOC) in Socorro, NM. In Socorro, astronomers and computer scientists used a special-purpose computer to digitally combine the signals from the satellite and the ground telescopes to make them all work together as a single, giant radio telescope. This dedicated machine, the VLBA Correlator, built as

  8. High energy astrophysics in radio-astronomical form

    International Nuclear Information System (INIS)

    Laan, H. van der

    1980-01-01

    The application of high energy astrophysics in observational astronomy, and in particular in radioastronomy, is considered. The current situation of extragalactic HEA, as brought to light by radio-astronomical techniques, is sketched. (C.F.)

  9. Radio astronomical interferometry and x-ray's computerized tomography

    Energy Technology Data Exchange (ETDEWEB)

    Rodriguez, L F [Universidad Nacional Autonoma de Mexico, Mexico City. Inst. de Astronomia

    1982-01-01

    Radio astronomical interferometry and computerized tomography are techniques of great importance for astronomy and medicine, respectively. In this paper we emphasize that both techniques are based on the same mathematical principles, and present them as an example of interaction between basic and applied science.

  10. Radio Astronomers Set New Standard for Accurate Cosmic Distance Measurement

    Science.gov (United States)

    1999-06-01

    A team of radio astronomers has used the National Science Foundation's Very Long Baseline Array (VLBA) to make the most accurate measurement ever made of the distance to a faraway galaxy. Their direct measurement calls into question the precision of distance determinations made by other techniques, including those announced last week by a team using the Hubble Space Telescope. The radio astronomers measured a distance of 23.5 million light-years to a galaxy called NGC 4258 in Ursa Major. "Ours is a direct measurement, using geometry, and is independent of all other methods of determining cosmic distances," said Jim Herrnstein, of the National Radio Astronomy Observatory (NRAO) in Socorro, NM. The team says their measurement is accurate to within less than a million light-years, or four percent. The galaxy is also known as Messier 106 and is visible with amateur telescopes. Herrnstein, along with James Moran and Lincoln Greenhill of the Harvard- Smithsonian Center for Astrophysics; Phillip Diamond, of the Merlin radio telescope facility at Jodrell Bank and the University of Manchester in England; Makato Inoue and Naomasa Nakai of Japan's Nobeyama Radio Observatory; Mikato Miyoshi of Japan's National Astronomical Observatory; Christian Henkel of Germany's Max Planck Institute for Radio Astronomy; and Adam Riess of the University of California at Berkeley, announced their findings at the American Astronomical Society's meeting in Chicago. "This is an incredible achievement to measure the distance to another galaxy with this precision," said Miller Goss, NRAO's Director of VLA/VLBA Operations. "This is the first time such a great distance has been measured this accurately. It took painstaking work on the part of the observing team, and it took a radio telescope the size of the Earth -- the VLBA -- to make it possible," Goss said. "Astronomers have sought to determine the Hubble Constant, the rate of expansion of the universe, for decades. This will in turn lead to an

  11. Radio Astronomers Get Their First Glimpse of Powerful Solar Storm

    Science.gov (United States)

    2001-08-01

    Astronomers have made the first radio-telescope images of a powerful coronal mass ejection on the Sun, giving them a long-sought glimpse of hitherto unseen aspects of these potentially dangerous events. "These observations are going to provide us with a new and unique tool for deciphering the mechanisms of coronal mass ejections and how they are related to other solar events," said Tim Bastian, an astronomer at the National Science Foundation's National Radio Astronomy Observatory (NRAO) in Charlottesville, Virginia. Radio image of coronal mass ejection; circle indicates the size and location of the Sun. White dots are where radio spectral measurements were made. Bastian, along with Monique Pick, Alain Kerdraon and Dalmiro Maia of the Paris Observatory, and Angelos Vourlidas of the Naval Research Laboratory in Washington, D.C., used a solar radio telescope in Nancay, France, to study a coronal mass ejection that occurred on April 20, 1998. Their results will be published in the September 1 edition of the Astrophysical Journal Letters. Coronal mass ejections are powerful magnetic explosions in the Sun's corona, or outer atmosphere, that can blast billions of tons of charged particles into interplanetary space at tremendous speeds. If the ejection is aimed in the direction of Earth, the speeding particles interact with our planet's magnetic field to cause auroral displays, radio-communication blackouts, and potentially damage satellites and electric-power systems. "Coronal mass ejections have been observed for many years, but only with visible-light telescopes, usually in space. While previous radio observations have provided us with powerful diagnostics of mass ejections and associated phenomena in the corona, this is the first time that one has been directly imaged in wavelengths other than visible light," Bastian said. "These new data from the radio observations give us important clues about how these very energetic events work," he added. The radio images show an

  12. Radio and Optical Telescopes for School Students and Professional Astronomers

    Science.gov (United States)

    Hosmer, Laura; Langston, G.; Heatherly, S.; Towner, A. P.; Ford, J.; Simon, R. S.; White, S.; O'Neil, K. L.; Haipslip, J.; Reichart, D.

    2013-01-01

    The NRAO 20m telescope is now on-line as a part of UNC's Skynet worldwide telescope network. The NRAO is completing integration of radio astronomy tools with the Skynet web interface. We present the web interface and astronomy projects that allow students and astronomers from all over the country to become Radio Astronomers. The 20 meter radio telescope at NRAO in Green Bank, WV is dedicated to public education and also is part of an experiment in public funding for astronomy. The telescope has a fantastic new web-based interface, with priority queuing, accommodating priority for paying customers and enabling free use of otherwise unused time. This revival included many software and hardware improvements including automatic calibration and improved time integration resulting in improved data processing, and a new ultra high resolution spectrometer. This new spectrometer is optimized for very narrow spectral lines, which will allow astronomers to study complex molecules and very cold regions of space in remarkable detail. In accordance with focusing on broader impacts, many public outreach and high school education activities have been completed with many confirmed future activities. The 20 meter is now a fully automated, powerful tool capable of professional grade results available to anyone in the world. Drop by our poster and try out real-time telescope control!

  13. Radio Astronomers Develop New Technique for Studying Dark Energy

    Science.gov (United States)

    2010-07-01

    Pioneering observations with the National Science Foundation's giant Robert C. Byrd Green Bank Telescope (GBT) have given astronomers a new tool for mapping large cosmic structures. The new tool promises to provide valuable clues about the nature of the mysterious "dark energy" believed to constitute nearly three-fourths of the mass and energy of the Universe. Dark energy is the label scientists have given to what is causing the Universe to expand at an accelerating rate. While the acceleration was discovered in 1998, its cause remains unknown. Physicists have advanced competing theories to explain the acceleration, and believe the best way to test those theories is to precisely measure large-scale cosmic structures. Sound waves in the matter-energy soup of the extremely early Universe are thought to have left detectable imprints on the large-scale distribution of galaxies in the Universe. The researchers developed a way to measure such imprints by observing the radio emission of hydrogen gas. Their technique, called intensity mapping, when applied to greater areas of the Universe, could reveal how such large-scale structure has changed over the last few billion years, giving insight into which theory of dark energy is the most accurate. "Our project mapped hydrogen gas to greater cosmic distances than ever before, and shows that the techniques we developed can be used to map huge volumes of the Universe in three dimensions and to test the competing theories of dark energy," said Tzu-Ching Chang, of the Academia Sinica in Taiwan and the University of Toronto. To get their results, the researchers used the GBT to study a region of sky that previously had been surveyed in detail in visible light by the Keck II telescope in Hawaii. This optical survey used spectroscopy to map the locations of thousands of galaxies in three dimensions. With the GBT, instead of looking for hydrogen gas in these individual, distant galaxies -- a daunting challenge beyond the technical

  14. Astronomical Data Processing Using SciQL, an SQL Based Query Language for Array Data

    Science.gov (United States)

    Zhang, Y.; Scheers, B.; Kersten, M.; Ivanova, M.; Nes, N.

    2012-09-01

    SciQL (pronounced as ‘cycle’) is a novel SQL-based array query language for scientific applications with both tables and arrays as first class citizens. SciQL lowers the entrance fee of adopting relational DBMS (RDBMS) in scientific domains, because it includes functionality often only found in mathematics software packages. In this paper, we demonstrate the usefulness of SciQL for astronomical data processing using examples from the Transient Key Project of the LOFAR radio telescope. In particular, how the LOFAR light-curve database of all detected sources can be constructed, by correlating sources across the spatial, frequency, time and polarisation domains.

  15. The Giant Radio Array for Neutrino Detection

    DEFF Research Database (Denmark)

    Martineau-Huynh, Olivier; Bustamante, Mauricio; Carvalho, Washington

    2017-01-01

    The Giant Radio Array for Neutrino Detection (GRAND) is a planned array of ~200 000 radio antennas deployed over ~200 000 km2 in a mountainous site. It aims primarly at detecting high-energy neutrinos via the observation of extensive air showers induced by the decay in the atmosphere of taus...

  16. Big Data Challenges for Large Radio Arrays

    Science.gov (United States)

    Jones, Dayton L.; Wagstaff, Kiri; Thompson, David; D'Addario, Larry; Navarro, Robert; Mattmann, Chris; Majid, Walid; Lazio, Joseph; Preston, Robert; Rebbapragada, Umaa

    2012-01-01

    Future large radio astronomy arrays, particularly the Square Kilometre Array (SKA), will be able to generate data at rates far higher than can be analyzed or stored affordably with current practices. This is, by definition, a "big data" problem, and requires an end-to-end solution if future radio arrays are to reach their full scientific potential. Similar data processing, transport, storage, and management challenges face next-generation facilities in many other fields.

  17. Radio Astronomers Lift "Fog" on Milky Way's Dark Heart: Black Hole Fits Inside Earth's Orbit

    Science.gov (United States)

    2004-04-01

    Thirty years after astronomers discovered the mysterious object at the exact center of our Milky Way Galaxy, an international team of scientists has finally succeeded in directly measuring the size of that object, which surrounds a black hole nearly four million times more massive than the Sun. This is the closest telescopic approach to a black hole so far and puts a major frontier of astrophysics within reach of future observations. The scientists used the National Science Foundation's Very Long Baseline Array (VLBA) radio telescope to make the breakthrough. Milky Way Nucleus The Milky Way's nucleus, as seen with the VLA. Sagittarius A* is the bright white dot at center. CREDIT: NRAO/AUI/NSF, Jun-Hui Zhao, W.M. Goss (Click on Image for Larger Version) "This is a big step forward," said Geoffrey Bower, of the University of California-Berkeley. "This is something that people have wanted to do for 30 years," since the Galactic center object, called Sagittarius A* (pronounced "A-star"), was discovered in 1974. The astronomers reported their research in the April 1 edition of Science Express. "Now we have a size for the object, but the mystery about its exact nature still remains," Bower added. The next step, he explained, is to learn its shape, "so we can tell if it is jets, a thin disk, or a spherical cloud." The Milky Way's center, 26,000 light-years from Earth, is obscured by dust, so visible-light telescopes cannot study the object. While radio waves from the Galaxy's central region can penetrate the dust, they are scattered by turbulent charged plasma in the space along the line of sight to Earth. This scattering had frustrated earlier attempts to measure the size of the central object, just as fog blurs the glare of distant lighthouses. "After 30 years, radio telescopes finally have lifted the fog and we can see what is going on," said Heino Falcke, of the Westerbork Radio Observatory in the Netherlands, another member of the research team. The bright, radio

  18. Radio Recombination Lines Their Physics and Astronomical Applications

    CERN Document Server

    Gordon, MA

    2008-01-01

    Includes the history of RRL detections, the astrophysics underlying their intensities and line shapes including topics like departures from LTE and Stark broadening, the maximum possible size of an atom, and descriptions of the astronomical topics for which RRLs have proved to be effective tools.

  19. A generalized measurement equation and van Cittert-Zernike theorem for wide-field radio astronomical interferometry

    Science.gov (United States)

    Carozzi, T. D.; Woan, G.

    2009-05-01

    We derive a generalized van Cittert-Zernike (vC-Z) theorem for radio astronomy that is valid for partially polarized sources over an arbitrarily wide field of view (FoV). The classical vC-Z theorem is the theoretical foundation of radio astronomical interferometry, and its application is the basis of interferometric imaging. Existing generalized vC-Z theorems in radio astronomy assume, however, either paraxiality (narrow FoV) or scalar (unpolarized) sources. Our theorem uses neither of these assumptions, which are seldom fulfiled in practice in radio astronomy, and treats the full electromagnetic field. To handle wide, partially polarized fields, we extend the two-dimensional (2D) electric field (Jones vector) formalism of the standard `Measurement Equation' (ME) of radio astronomical interferometry to the full three-dimensional (3D) formalism developed in optical coherence theory. The resulting vC-Z theorem enables full-sky imaging in a single telescope pointing, and imaging based not only on standard dual-polarized interferometers (that measure 2D electric fields) but also electric tripoles and electromagnetic vector-sensor interferometers. We show that the standard 2D ME is easily obtained from our formalism in the case of dual-polarized antenna element interferometers. We also exploit an extended 2D ME to determine that dual-polarized interferometers can have polarimetric aberrations at the edges of a wide FoV. Our vC-Z theorem is particularly relevant to proposed, and recently developed, wide FoV interferometers such as Low Frequency Array (LOFAR) and Square Kilometer Array (SKA), for which direction-dependent effects will be important.

  20. The Giant Radio Array for Neutrino Detection

    Directory of Open Access Journals (Sweden)

    Martineau-Huynh Olivier

    2016-01-01

    Full Text Available High-energy neutrino astronomy will probe the working of the most violent phenomena in the Universe. The Giant Radio Array for Neutrino Detection (GRAND project consists of an array of ∼ 105 radio antennas deployed over ∼ 200 000 km2 in a mountainous site. It aims at detecting high-energy neutrinos via the measurement of air showers induced by the decay in the atmosphere of τ leptons produced by the interaction of cosmic neutrinos under the Earth surface. Our objective with GRAND is to reach a neutrino sensitivity of 5 × 10−11E−2 GeV−1 cm−2 s−1 sr−1 above 3 × 1016 eV. This sensitivity ensures the detection of cosmogenic neutrinos in the most pessimistic source models, and up to 100 events per year are expected for the standard models. GRAND would also probe the neutrino signals produced at the potential sources of UHECRs.

  1. The Giant Radio Array for Neutrino Detection

    Directory of Open Access Journals (Sweden)

    Martineau-Huynh Olivier

    2017-01-01

    Full Text Available The Giant Radio Array for Neutrino Detection (GRAND is a planned array of ~ 2·105 radio antennas deployed over ~ 200 000 km2 in a mountainous site. It aims primarly at detecting high-energy neutrinos via the observation of extensive air showers induced by the decay in the atmosphere of taus produced by the interaction of cosmic neutrinos under the Earth surface. GRAND aims at reaching a neutrino sensitivity of 5 · 10−11 E−2 GeV−1 cm−2 s−1 sr−1 above 3 · 1016 eV. This ensures the detection of cosmogenic neutrinos in the most pessimistic source models, and ~50 events per year are expected for the standard models. The instrument will also detect UHECRs and possibly FRBs. Here we show how our preliminary design should enable us to reach our sensitivity goals, and discuss the steps to be taken to achieve GRAND, while the compelling science case for GRAND is discussed in more details in [1].

  2. PySE: Python Source Extractor for radio astronomical images

    Science.gov (United States)

    Spreeuw, Hanno; Swinbank, John; Molenaar, Gijs; Staley, Tim; Rol, Evert; Sanders, John; Scheers, Bart; Kuiack, Mark

    2018-05-01

    PySE finds and measures sources in radio telescope images. It is run with several options, such as the detection threshold (a multiple of the local noise), grid size, and the forced clean beam fit, followed by a list of input image files in standard FITS or CASA format. From these, PySe provides a list of found sources; information such as the calculated background image, source list in different formats (e.g. text, region files importable in DS9), and other data may be saved. PySe can be integrated into a pipeline; it was originally written as part of the LOFAR Transient Detection Pipeline (TraP, ascl:1412.011).

  3. Astronomers Break Ground on Atacama Large Millimeter Array (ALMA) - World's Largest Millimeter Wavelength Telescope

    Science.gov (United States)

    2003-11-01

    will combine the signals from all its antennas (one pair of antennas at a time) to simulate a telescope the size of the distance between the antennas. With 64 antennas, ALMA will generate 2016 individual antenna pairs ("baselines") during the observations. To handle this enormous amount of data, ALMA will rely on a very powerful, specialized computer (a "correlator"), which will perform 16,000 million million (1.6 x 10 16 ) operations per second. Currently, two prototype ALMA antennas are undergoing rigorous testing at the NRAO's Very Large Array site, near Socorro, New Mexico, USA. International collaboration For this ambitious project, ALMA has become a joint effort among many nations and scientific institutions. In Europe, ESO leads on behalf of its ten member countries (Belgium, Denmark, France, Germany, Italy, The Netherlands, Portugal, Sweden, Switzerland and the United Kingdom) and Spain. Japan may join in 2004, bringing enhancements to the project. Given the participation of North America, this will be the first truly global project of ground-based astronomy, an essential development in view of the increasing technological sophistication and the high costs of front-line astronomy installations. The first submillimeter telescope in the southern hemisphere was the 15-m Swedish-ESO Submillimetre Telescope (SEST) which was installed at the ESO La Silla Observatory in 1987. It has since been used extensively by astronomers, mostly from ESO's member states. SEST has now been decommissioned and a new submillimetre telescope, APEX, is about to commence operations at Chajnantor. APEX, which is a joint project between ESO, the Max Planck Institute for Radio Astronomy in Bonn (Germany), and the Onsala Space Observatory (Sweden), is an antenna comparable to the ALMA antennas.

  4. Orbiting low frequency array for radio astronomy

    NARCIS (Netherlands)

    Rajan, Rai Thilak; Rajan, Raj; Engelen, Steven; Bentum, Marinus Jan; Verhoeven, Chris

    2011-01-01

    Recently new and interesting science drivers have emerged for very low frequency radio astronomy from 0.3 MHz to 30 MHz. However Earth bound radio observations at these wavelengths are severely hampered by ionospheric distortions, man made interference, solar flares and even complete reflection

  5. Making waves the story of Ruby Payne-Scott : Australian pioneer radio astronomer

    CERN Document Server

    Goss, M

    2013-01-01

    This book is an abbreviated, partly re-written version of "Under the Radar - The First Woman in Radio Astronomy: Ruby Payne-Scott." It addresses a general readership interested in historical and sociological aspects of astronomy and presents the biography of Ruby Payne-Scott (1912 – 1981). As the first female radio astronomer (and one of the first people in the world to consider radio astronomy), she made classic contributions to solar radio physics. She also played a major role in the design of the Australian government's Council for Scientific and Industrial Research radars, which were in turn of vital importance in the Southwest Pacific Theatre in World War II. These radars were used by military personnel from Australia, the United States and New Zealand. From a sociological perspective, her career offers many examples of the perils of being a female academic in the first half of the 20th century. Written in an engaging style and complemented by many historical photographs, this book offers fascinating...

  6. Subarray Processing for Projection-based RFI Mitigation in Radio Astronomical Interferometers

    Science.gov (United States)

    Burnett, Mitchell C.; Jeffs, Brian D.; Black, Richard A.; Warnick, Karl F.

    2018-04-01

    Radio Frequency Interference (RFI) is a major problem for observations in Radio Astronomy (RA). Adaptive spatial filtering techniques such as subspace projection are promising candidates for RFI mitigation; however, for radio interferometric imaging arrays, these have primarily been used in engineering demonstration experiments rather than mainstream scientific observations. This paper considers one reason that adoption of such algorithms is limited: RFI decorrelates across the interferometric array because of long baseline lengths. This occurs when the relative RFI time delay along a baseline is large compared to the frequency channel inverse bandwidth used in the processing chain. Maximum achievable excision of the RFI is limited by covariance matrix estimation error when identifying interference subspace parameters, and decorrelation of the RFI introduces errors that corrupt the subspace estimate, rendering subspace projection ineffective over the entire array. In this work, we present an algorithm that overcomes this challenge of decorrelation by applying subspace projection via subarray processing (SP-SAP). Each subarray is designed to have a set of elements with high mutual correlation in the interferer for better estimation of subspace parameters. In an RFI simulation scenario for the proposed ngVLA interferometric imaging array with 15 kHz channel bandwidth for correlator processing, we show that compared to the former approach of applying subspace projection on the full array, SP-SAP improves mitigation of the RFI on the order of 9 dB. An example of improved image synthesis and reduced RFI artifacts for a simulated image “phantom” using the SP-SAP algorithm is presented.

  7. DETECTION OF FAST TRANSIENTS WITH RADIO INTERFEROMETRIC ARRAYS

    International Nuclear Information System (INIS)

    Bhat, N. D. R.; Chengalur, J. N.; Gupta, Y.; Prasad, J.; Roy, J.; Kudale, S. S.; Cox, P. J.; Bailes, M.; Burke-Spolaor, S.; Van Straten, W.

    2013-01-01

    Next-generation radio arrays, including the Square Kilometre Array (SKA) and its pathfinders, will open up new avenues for exciting transient science at radio wavelengths. Their innovative designs, comprising a large number of small elements, pose several challenges in digital processing and optimal observing strategies. The Giant Metre-wave Radio Telescope (GMRT) presents an excellent test-bed for developing and validating suitable observing modes and strategies for transient experiments with future arrays. Here we describe the first phase of the ongoing development of a transient detection system for GMRT that is planned to eventually function in a commensal mode with other observing programs. It capitalizes on the GMRT's interferometric and sub-array capabilities, and the versatility of a new software backend. We outline considerations in the plan and design of transient exploration programs with interferometric arrays, and describe a pilot survey that was undertaken to aid in the development of algorithms and associated analysis software. This survey was conducted at 325 and 610 MHz, and covered 360 deg 2 of the sky with short dwell times. It provides large volumes of real data that can be used to test the efficacies of various algorithms and observing strategies applicable for transient detection. We present examples that illustrate the methodologies of detecting short-duration transients, including the use of sub-arrays for higher resilience to spurious events of terrestrial origin, localization of candidate events via imaging, and the use of a phased array for improved signal detection and confirmation. In addition to demonstrating applications of interferometric arrays for fast transient exploration, our efforts mark important steps in the roadmap toward SKA-era science.

  8. Detection of Fast Transients with Radio Interferometric Arrays

    Science.gov (United States)

    Bhat, N. D. R.; Chengalur, J. N.; Cox, P. J.; Gupta, Y.; Prasad, J.; Roy, J.; Bailes, M.; Burke-Spolaor, S.; Kudale, S. S.; van Straten, W.

    2013-05-01

    Next-generation radio arrays, including the Square Kilometre Array (SKA) and its pathfinders, will open up new avenues for exciting transient science at radio wavelengths. Their innovative designs, comprising a large number of small elements, pose several challenges in digital processing and optimal observing strategies. The Giant Metre-wave Radio Telescope (GMRT) presents an excellent test-bed for developing and validating suitable observing modes and strategies for transient experiments with future arrays. Here we describe the first phase of the ongoing development of a transient detection system for GMRT that is planned to eventually function in a commensal mode with other observing programs. It capitalizes on the GMRT's interferometric and sub-array capabilities, and the versatility of a new software backend. We outline considerations in the plan and design of transient exploration programs with interferometric arrays, and describe a pilot survey that was undertaken to aid in the development of algorithms and associated analysis software. This survey was conducted at 325 and 610 MHz, and covered 360 deg2 of the sky with short dwell times. It provides large volumes of real data that can be used to test the efficacies of various algorithms and observing strategies applicable for transient detection. We present examples that illustrate the methodologies of detecting short-duration transients, including the use of sub-arrays for higher resilience to spurious events of terrestrial origin, localization of candidate events via imaging, and the use of a phased array for improved signal detection and confirmation. In addition to demonstrating applications of interferometric arrays for fast transient exploration, our efforts mark important steps in the roadmap toward SKA-era science.

  9. A Radio-Frequency-over-Fiber link for large-array radio astronomy applications

    International Nuclear Information System (INIS)

    Mena, J; Bandura, K; Cliche, J-F; Dobbs, M; Gilbert, A; Tang, Q Y

    2013-01-01

    A prototype 425-850 MHz Radio-Frequency-over-Fiber (RFoF) link for the Canadian Hydrogen Intensity Mapping Experiment (CHIME) is presented. The design is based on a directly modulated Fabry-Perot (FP) laser, operating at ambient temperature, and a single-mode fiber. The dynamic performance, gain stability, and phase stability of the RFoF link are characterized. Tests on a two-element interferometer built at the Dominion Radio Astrophysical Observatory for CHIME prototyping demonstrate that RFoF can be successfully used as a cost-effective solution for analog signal transport on the CHIME telescope and other large-array radio astronomy applications

  10. Radio detection of high-energy cosmic rays with the Auger Engineering Radio Array

    Science.gov (United States)

    Schröder, Frank G.; Pierre Auger Collaboration

    2016-07-01

    The Auger Engineering Radio Array (AERA) is an enhancement of the Pierre Auger Observatory in Argentina. Covering about 17km2, AERA is the world-largest antenna array for cosmic-ray observation. It consists of more than 150 antenna stations detecting the radio signal emitted by air showers, i.e., cascades of secondary particles caused by primary cosmic rays hitting the atmosphere. At the beginning, technical goals had been in focus: first of all, the successful demonstration that a large-scale antenna array consisting of autonomous stations is feasible. Moreover, techniques for calibration of the antennas and time calibration of the array have been developed, as well as special software for the data analysis. Meanwhile physics goals come into focus. At the Pierre Auger Observatory air showers are simultaneously detected by several detector systems, in particular water-Cherenkov detectors at the surface, underground muon detectors, and fluorescence telescopes, which enables cross-calibration of different detection techniques. For the direction and energy of air showers, the precision achieved by AERA is already competitive; for the type of primary particle, several methods are tested and optimized. By combining AERA with the particle detectors we aim for a better understanding of cosmic rays in the energy range from approximately 0.3 to 10 EeV, i.e., significantly higher energies than preceding radio arrays.

  11. Developments of FPGA-based digital back-ends for low frequency antenna arrays at Medicina radio telescopes

    Science.gov (United States)

    Naldi, G.; Bartolini, M.; Mattana, A.; Pupillo, G.; Hickish, J.; Foster, G.; Bianchi, G.; Lingua, A.; Monari, J.; Montebugnoli, S.; Perini, F.; Rusticelli, S.; Schiaffino, M.; Virone, G.; Zarb Adami, K.

    In radio astronomy Field Programmable Gate Array (FPGA) technology is largely used for the implementation of digital signal processing techniques applied to antenna arrays. This is mainly due to the good trade-off among computing resources, power consumption and cost offered by FPGA chip compared to other technologies like ASIC, GPU and CPU. In the last years several digital backend systems based on such devices have been developed at the Medicina radio astronomical station (INAF-IRA, Bologna, Italy). Instruments like FX correlator, direct imager, beamformer, multi-beam system have been successfully designed and realized on CASPER (Collaboration for Astronomy Signal Processing and Electronics Research, https://casper.berkeley.edu) processing boards. In this paper we present the gained experience in this kind of applications.

  12. Results from and prospects for the Auger Engineering Radio Array

    Directory of Open Access Journals (Sweden)

    van den Berg A.M.

    2013-06-01

    Full Text Available The Auger Engineering Radio Array (AERA is one of the low-energy enhancements of the Pierre Auger Observatory. AERA is based on experience obtained with the LOPES and CODALEMA experiments in Europe and aims to study in the MHz region the details of the emission mechanism of radio signals from extensive air showers. The data from AERA will be used to assess the sensitivity of MHz radiation to the mass composition of cosmic rays. Because of its energy threshold at 2 × 1017 eV the dip region in the cosmic-ray flux spectrum can be studied in detail. We present first results of AERA and of its prototypes and we provide an outlook towards the future.

  13. Generation of OAM Radio Waves Using Circular Vivaldi Antenna Array

    Directory of Open Access Journals (Sweden)

    Changjiang Deng

    2013-01-01

    Full Text Available This paper gives a feasible and simple solution of generating OAM-carrying radio beams. Eight Vivaldi antenna elements connect sequentially and fold into a hollow cylinder. The circular Vivaldi antenna array is fed with unit amplitude but with a successive phase difference from element to element. By changing the phase difference at the steps of 0, ±45°, ±90°, ±135°, and 180°, the OAM radio beam can be generated with mode numbers 0, ±1, ±2, ±3, and 4. Simulations show that the OAM states of ±2 and ±3 are the same as the traditional states, while the OAM states of 0, ±1, and 4 differ at the boresight. This phenomenon can be explained by the radiation pattern difference between Vivaldi antenna and tripole antenna. A solution of distinguishing OAM states is also proposed. The mode number of OAM can be distinguished with only 2 receivers.

  14. The Askaryan Radio Array: Overview and Recent Results

    Science.gov (United States)

    Pfendner, Carl; Askaryan Radio Array (ARA) Collaboration

    2017-01-01

    The Askaryan Radio Array (ARA) is radio frequency observatory under construction at the South Pole that is searching for ultrahigh energy neutrinos via the Askaryan effect. By instrumenting several gigatons of Antarctic glacial ice, the experiment aims to detect a flux of neutrinos above 10 PeV in energy. The measurement of this expected flux of neutrinos would provide information about the highest energy processes in the universe with no local horizon. The full detector consisting of 37 stations is being constructed in a phased deployment with 3 stations already in place and two more planned for deployment in the 2017-2018 season. Recent results from an analysis of data from two stations and a search for neutrinos correlated with gamma ray bursts are presented here. Funding provided by NSF CAREER Award 1255557, NSF ARA Grant 1404266, BigData Grant 1250720.

  15. American West Tephras – Geomagnetic polarity events redefined through calibration of radio-isotopic and astronomical time

    DEFF Research Database (Denmark)

    Rivera, Tiffany; Storey, Michael

    calibration. Although this geomagnetic event is not part of the most recent geologic timescale, refined ages on short-lived excursions could hold importance to understanding time scales for the wavering nature of Earth’s magnetic field. We propose a new 40Ar/39Ar age for the Quaternary mineral dating standard......The foundation of the EARTHTIME/GTSnext initiative seeks to construct an internally consistent geologic timescale based on astronomical and radio-isotopic geochronology. American west tephras offer a prime opportunity to integrate these two independent timescales with the geomagnetic timescale....... Using an astronomically calibrated age for the monitor mineral Fish Canyon sanidine (FCs;28.201 ± 0.046 Ma, Kuiper, et al., 2008), ages of Pleistocene geomagnetic polarity events are reexamined. Of particular interest, the Quaternary mineral dating standard Alder Creek sandine (ACs) is the type locality...

  16. Metal-Containing Molecules Beyond the Solar System: a Laboratory and Radio Astronomical Perspective

    Science.gov (United States)

    Ziurys, L. M.

    2010-06-01

    Although the history of interstellar molecules began around 1970, with the millimeter-wave detection of CO in the Orion Nebula, metal-containing species have been somewhat elusive for astronomical searches. Only in the past two decades have metal-bearing molecules been identified in space, starting with metal halides (NaCl, KCl, AlCl, and AlF), and then metal cyanide and isocyanide species (MgNC, MgCN, NaCN, and AlNC). Moreover, the metal-containing molecules seemed to be present in a single astronomical object: the envelope of a dying, carbon-rich star, IRC+10216. However, with improvements both in laboratory spectroscopy and telescope sensitivity, it is becoming clear that the relevance of metal-containing species in astrophysics is increasing. Metal oxide and hydroxide species, such as AlO and AlOH, have recently been identified in interstellar space. Metal-containing molecules are now being found in other astronomical sources, such as the oxygen-rich shell surrounding VY Canis Majoris, a supergiant star. These new astronomical discoveries will be presented, as well as the laboratory measurements that made them possible. New directions in rotational spectroscopy of metal-bearing molecules will also be discussed.

  17. Searching for giga-Jansky fast radio bursts from the Milky Way with a global array of low-cost radio receivers

    Science.gov (United States)

    Maoz, Dan; Loeb, Abraham

    2017-06-01

    If fast radio bursts (FRBs) originate from galaxies at cosmological distances, then their all-sky rate implies that the Milky Way may host an FRB every 30-1500 yr, on average. If many FRBs persistently repeat for decades or more, a local giant FRB could be active now, with 1 GHz radio pulses of flux ˜3 × 1010 Jy, comparable with the fluxes and frequencies detectable by cellular communication devices (cell phones, Wi-Fi and GPS). We propose searching for Galactic FRBs using a global array of low-cost radio receivers. One possibility is the ˜1 GHz communication channel in cellular phones, through a Citizens-Science downloadable application. Participating phones would continuously listen for and record candidate FRBs and would periodically upload information to a central data-processing website which will identify the signature of a real, globe-encompassing, FRB from an astronomical distance. Triangulation of the GPS-based pulse arrival times reported from different Earth locations will provide the FRB sky position, potentially to arcsecond accuracy. Pulse arrival times versus frequency, from reports from phones operating at diverse frequencies, or from fast signal de-dispersion by the application, will yield the dispersion measure (DM). Compared to a Galactic DM model, it will indicate the source distance within the Galaxy. A variant approach uses the built-in ˜100 MHz FM-radio receivers present in cell phones for an FRB search at lower frequencies. Alternatively, numerous 'software-defined radio' devices, costing ˜$10 US each, could be deployed and plugged into USB ports of personal computers (particularly in radio-quiet locations) to establish the global network of receivers.

  18. Daris, a low-frequency distributed aperture array for radio astronomy in space

    NARCIS (Netherlands)

    Boonstra, A.J.; Saks, N.; Bentum, Marinus Jan; van 't Klooster, K.; Falcke, H.

    2010-01-01

    DARIS (Distributed Aperture Array for Radio Astronomy in Space) is a radio astronomy space mission concept aimed at observing the low-frequency radio sky in the range 1-10 MHz. Because of the Earth's ionospheric disturbances and opaqueness, this frequency range can only be observed from space. The

  19. The Very Large Array: Pioneering New Directions in Radio Astronomy

    Science.gov (United States)

    McKinnon, Mark

    2018-01-01

    The Very Large Array (VLA) started science operations in 1980 and was rechristened the Jansky VLA after a major upgrade to its electronics system was completed in 2012. The VLA plays a prominent role in scientific discovery through studies of the Solar System, star and planet formation, galaxy formation, and time domain astronomy. It has attained iconic status as one of the most scientifically productive telescopes on EarthIn 2017, three major initiatives were launched at the VLA with the goal of maintaining its leadership role and impact in radio astronomy in the near and long term future:1. In September, the VLA embarked upon the VLA Sky Survey (VLASS), the highest resolution survey ever undertaken at radio wavelengths. The survey was planned in consultation with the astronomy community and will be used to search for transients, study the polarization properties of extragalactic radio sources, and study highly obscured sources in our Galaxy.2. Detailed planning for a next generation VLA (ngVLA) began in earnest in 2017. The ngVLA will open a new window on the Universe through ultra-sensitive imaging of thermal line and continuum emission down to milliarcsecond resolution, as well as unprecedented broad-band continuum polarimetric imaging of non-thermal processes. A proposal for the instrument will be submitted to the 2020 Decadal Survey.3. A multi-year program to replace the 40+ year old infrastructure at the VLA site was initiated in 2017. The program includes the replacement of the VLA’s electrical infrastructure in 2018, improvements to the VLA rail system, and the replacement of heavy maintenance equipment.The VLA continued to play a major role in discovering and explaining the physics of transient phenomena in 2017, to include fast transients, such as fast radio bursts, and long time scale transients, such as novae, tidal disruption events, and gamma-ray bursts.More thorough descriptions of the VLASS and ngVLA, along with the science that can be done with

  20. Highlighting the history of Japanese radio astronomy. 5: The 1950 Osaka solar grating array proposal

    Science.gov (United States)

    Wendt, Harry; Orchiston, Wayne; Ishiguro, Masato; Nakamura, Tsuko

    2017-04-01

    In November 1950, a paper was presented at the 5th Annual Assembly of the Physical Society of Japan that outlined the plan for a radio frequency grating array, designed to provide high-resolution observations of solar radio emission at 3.3 GHz. This short paper provides details of the invention of this array, which occurred independently of W.N. Christiansen's invention of the solar grating array in Australia at almost the same time.

  1. Low Dimensional Embedding of Climate Data for Radio Astronomical Site Testing in the Colombian Andes

    Science.gov (United States)

    Chaparro Molano, Germán; Ramírez Suárez, Oscar Leonardo; Restrepo Gaitán, Oscar Alberto; Marcial Martínez Mercado, Alexander

    2017-10-01

    We set out to evaluate the potential of the Colombian Andes for millimeter-wave astronomical observations. Previous studies for astronomical site testing in this region have suggested that nighttime humidity and cloud cover conditions make most sites unsuitable for professional visible-light observations. Millimeter observations can be done during the day, but require that the precipitable water vapor column above a site stays below ˜10 mm. Due to a lack of direct radiometric or radiosonde measurements, we present a method for correlating climate data from weather stations to sites with a low precipitable water vapor column. We use unsupervised learning techniques to low dimensionally embed climate data (precipitation, rain days, relative humidity, and sunshine duration) in order to group together stations with similar long-term climate behavior. The data were taken over a period of 30 years by 2046 weather stations across the Colombian territory. We find six regions with unusually dry, clear-sky conditions, ranging in elevations from 2200 to 3800 masl. We evaluate the suitability of each region using a quality index derived from a Bayesian probabilistic analysis of the station type and elevation distributions. Two of these regions show a high probability of having an exceptionally low precipitable water vapor column. We compared our results with global precipitable water vapor maps and find a plausible geographical correlation with regions with low water vapor columns (˜10 mm) at an accuracy of ˜20 km. Our methods can be applied to similar data sets taken in other countries as a first step toward astronomical site evaluation.

  2. Observatory Sponsoring Astronomical Image Contest

    Science.gov (United States)

    2005-05-01

    Forget the headphones you saw in the Warner Brothers thriller Contact, as well as the guttural throbs emanating from loudspeakers at the Very Large Array in that 1997 movie. In real life, radio telescopes aren't used for "listening" to anything - just like visible-light telescopes, they are used primarily to make images of astronomical objects. Now, the National Radio Astronomy Observatory (NRAO) wants to encourage astronomers to use radio-telescope data to make truly compelling images, and is offering cash prizes to winners of a new image contest. Radio Galaxy Fornax A Radio Galaxy Fornax A Radio-optical composite image of giant elliptical galaxy NGC 1316, showing the galaxy (center), a smaller companion galaxy being cannibalized by NGC 1316, and the resulting "lobes" (orange) of radio emission caused by jets of particles spewed from the core of the giant galaxy Click on image for more detail and images CREDIT: Fomalont et al., NRAO/AUI/NSF "Astronomy is a very visual science, and our radio telescopes are capable of producing excellent images. We're sponsoring this contest to encourage astronomers to make the extra effort to turn good images into truly spectacular ones," said NRAO Director Fred K.Y. Lo. The contest, offering a grand prize of $1,000, was announced at the American Astronomical Society's meeting in Minneapolis, Minnesota. The image contest is part of a broader NRAO effort to make radio astronomical data and images easily accessible and widely available to scientists, students, teachers, the general public, news media and science-education professionals. That effort includes an expanded image gallery on the observatory's Web site. "We're not only adding new radio-astronomy images to our online gallery, but we're also improving the organization and accessibility of the images," said Mark Adams, head of education and public outreach (EPO) at NRAO. "Our long-term goal is to make the NRAO Image Gallery an international resource for radio astronomy imagery

  3. The Engineering Development Array: A Low Frequency Radio Telescope Utilising SKA Precursor Technology

    Science.gov (United States)

    Wayth, Randall; Sokolowski, Marcin; Booler, Tom; Crosse, Brian; Emrich, David; Grootjans, Robert; Hall, Peter J.; Horsley, Luke; Juswardy, Budi; Kenney, David; Steele, Kim; Sutinjo, Adrian; Tingay, Steven J.; Ung, Daniel; Walker, Mia; Williams, Andrew; Beardsley, A.; Franzen, T. M. O.; Johnston-Hollitt, M.; Kaplan, D. L.; Morales, M. F.; Pallot, D.; Trott, C. M.; Wu, C.

    2017-08-01

    We describe the design and performance of the Engineering Development Array, which is a low-frequency radio telescope comprising 256 dual-polarisation dipole antennas working as a phased array. The Engineering Development Array was conceived of, developed, and deployed in just 18 months via re-use of Square Kilometre Array precursor technology and expertise, specifically from the Murchison Widefield Array radio telescope. Using drift scans and a model for the sky brightness temperature at low frequencies, we have derived the Engineering Development Array's receiver temperature as a function of frequency. The Engineering Development Array is shown to be sky-noise limited over most of the frequency range measured between 60 and 240 MHz. By using the Engineering Development Array in interferometric mode with the Murchison Widefield Array, we used calibrated visibilities to measure the absolute sensitivity of the array. The measured array sensitivity matches very well with a model based on the array layout and measured receiver temperature. The results demonstrate the practicality and feasibility of using Murchison Widefield Array-style precursor technology for Square Kilometre Array-scale stations. The modular architecture of the Engineering Development Array allows upgrades to the array to be rolled out in a staged approach. Future improvements to the Engineering Development Array include replacing the second stage beamformer with a fully digital system, and to transition to using RF-over-fibre for the signal output from first stage beamformers.

  4. Radio astronomy

    Energy Technology Data Exchange (ETDEWEB)

    Nagnibeda, V.G.

    1981-01-01

    The history of radio astronomical observations at the Astronomical Observatory of Leningrad State University is reviewed. Various facilities are described, and methods and instruments used are discussed. Some results are summarized for radio observations of the sun, including observations of local sources of solar radio emission, the absolute solar radio flux, and radio emission from filaments and prominences.

  5. The Statistics of Radio Astronomical Polarimetry: Disjoint, Superposed, and Composite Samples

    Energy Technology Data Exchange (ETDEWEB)

    Straten, W. van [Centre for Astrophysics and Supercomputing, Swinburne University of Technology, Hawthorn, VIC 3122 (Australia); Tiburzi, C., E-mail: willem.van.straten@aut.ac.nz [Max-Planck-Institut für Radioastronomie, Auf dem Hügel 69, D-53121 Bonn (Germany)

    2017-02-01

    A statistical framework is presented for the study of the orthogonally polarized modes of radio pulsar emission via the covariances between the Stokes parameters. To accommodate the typically heavy-tailed distributions of single-pulse radio flux density, the fourth-order joint cumulants of the electric field are used to describe the superposition of modes with arbitrary probability distributions. The framework is used to consider the distinction between superposed and disjoint modes, with particular attention to the effects of integration over finite samples. If the interval over which the polarization state is estimated is longer than the timescale for switching between two or more disjoint modes of emission, then the modes are unresolved by the instrument. The resulting composite sample mean exhibits properties that have been attributed to mode superposition, such as depolarization. Because the distinction between disjoint modes and a composite sample of unresolved disjoint modes depends on the temporal resolution of the observing instrumentation, the arguments in favor of superposed modes of pulsar emission are revisited, and observational evidence for disjoint modes is described. In principle, the four-dimensional covariance matrix that describes the distribution of sample mean Stokes parameters can be used to distinguish between disjoint modes, superposed modes, and a composite sample of unresolved disjoint modes. More comprehensive and conclusive interpretation of the covariance matrix requires more detailed consideration of various relevant phenomena, including temporally correlated subpulse modulation (e.g., jitter), statistical dependence between modes (e.g., covariant intensities and partial coherence), and multipath propagation effects (e.g., scintillation and scattering).

  6. HIGH-FIDELITY RADIO ASTRONOMICAL POLARIMETRY USING A MILLISECOND PULSAR AS A POLARIZED REFERENCE SOURCE

    Energy Technology Data Exchange (ETDEWEB)

    Van Straten, W., E-mail: vanstraten.willem@gmail.com [Centre for Astrophysics and Supercomputing, Swinburne University of Technology, Hawthorn, VIC 3122 (Australia)

    2013-01-15

    A new method of polarimetric calibration is presented in which the instrumental response is derived from regular observations of PSR J0437-4715 based on the assumption that the mean polarized emission from this millisecond pulsar remains constant over time. The technique is applicable to any experiment in which high-fidelity polarimetry is required over long timescales; it is demonstrated by calibrating 7.2 years of high-precision timing observations of PSR J1022+1001 made at the Parkes Observatory. Application of the new technique followed by arrival time estimation using matrix template matching yields post-fit residuals with an uncertainty-weighted standard deviation of 880 ns, two times smaller than that of arrival time residuals obtained via conventional methods of calibration and arrival time estimation. The precision achieved by this experiment yields the first significant measurements of the secular variation of the projected semimajor axis, the precession of periastron, and the Shapiro delay; it also places PSR J1022+1001 among the 10 best pulsars regularly observed as part of the Parkes Pulsar Timing Array (PPTA) project. It is shown that the timing accuracy of a large fraction of the pulsars in the PPTA is currently limited by the systematic timing error due to instrumental polarization artifacts. More importantly, long-term variations of systematic error are correlated between different pulsars, which adversely affects the primary objectives of any pulsar timing array experiment. These limitations may be overcome by adopting the techniques presented in this work, which relax the demand for instrumental polarization purity and thereby have the potential to reduce the development cost of next-generation telescopes such as the Square Kilometre Array.

  7. The Use of Self-scanned Silicon Photodiode Arrays for Astronomical Spectrophotometry

    Science.gov (United States)

    Cochran, A. L.

    1984-01-01

    The use of a Reticon self scanned silicon photodiode array for precision spectrophotometry is discussed. It is shown that internal errors are + or - 0.003 mag. Observations obtained with a photodiode array are compared with observations obtained with other types of detectors with agreement, from 3500 A to 10500 A, of 1%. The photometric properties of self scanned photodiode arrays are discussed. Potential pitfalls are given.

  8. THE STATISTICS OF RADIO ASTRONOMICAL POLARIMETRY: BRIGHT SOURCES AND HIGH TIME RESOLUTION

    International Nuclear Information System (INIS)

    Van Straten, W.

    2009-01-01

    A four-dimensional statistical description of electromagnetic radiation is developed and applied to the analysis of radio pulsar polarization. The new formalism provides an elementary statistical explanation of the modal-broadening phenomenon in single-pulse observations. It is also used to argue that the degree of polarization of giant pulses has been poorly defined in past studies. Single- and giant-pulse polarimetry typically involves sources with large flux-densities and observations with high time-resolution, factors that necessitate consideration of source-intrinsic noise and small-number statistics. Self-noise is shown to fully explain the excess polarization dispersion previously noted in single-pulse observations of bright pulsars, obviating the need for additional randomly polarized radiation. Rather, these observations are more simply interpreted as an incoherent sum of covariant, orthogonal, partially polarized modes. Based on this premise, the four-dimensional covariance matrix of the Stokes parameters may be used to derive mode-separated pulse profiles without any assumptions about the intrinsic degrees of mode polarization. Finally, utilizing the small-number statistics of the Stokes parameters, it is established that the degree of polarization of an unresolved pulse is fundamentally undefined; therefore, previous claims of highly polarized giant pulses are unsubstantiated.

  9. Adaptive algorithm based on antenna arrays for radio communication systems

    Directory of Open Access Journals (Sweden)

    Fedosov Valentin

    2017-01-01

    Full Text Available Trends in the modern world increasingly lead to the growing popularity of wireless technologies. This is possible due to the rapid development of mobile communications, the Internet gaining high popularity, using wireless networks at enterprises, offices, buildings, etc. It requires advanced network technologies with high throughput capacity to meet the needs of users. To date, a popular destination is the development of spatial signal processing techniques allowing to increase spatial bandwidth of communication channels. The most popular method is spatial coding MIMO to increase data transmission speed which is carried out due to several spatial streams emitted by several antennas. Another advantage of this technology is the bandwidth increase to be achieved without expanding the specified frequency range. Spatial coding methods are even more attractive due to a limited frequency resource. Currently, there is an increasing use of wireless communications (for example, WiFi and WiMAX in information transmission networks. One of the main problems of evolving wireless systems is the need to increase bandwidth and improve the quality of service (reducing the error probability. Bandwidth can be increased by expanding the bandwidth or increasing the radiated power. Nevertheless, the application of these methods has some drawbacks, due to the requirements of biological protection and electromagnetic compatibility, the increase of power and the expansion of the frequency band is limited. This problem is especially relevant in mobile (cellular communication systems and wireless networks operating in difficult signal propagation conditions. One of the most effective ways to solve this problem is to use adaptive antenna arrays with weakly correlated antenna elements. Communication systems using such antennas are called MIMO systems (Multiple Input Multiple Output multiple input - multiple outputs. At the moment, existing MIMO-idea implementations do not

  10. Evaluation of Rockwell HgCdTe arrays for astronomical use

    Science.gov (United States)

    Lebofsky, M. J.; Montgomery, E. F.; Kailey, W. F.

    1986-01-01

    The 32 x 32 HgCdTe array manufactured by Rockwell International was proven to be a highly competitive detector type for use at wavelengths shorter than 2.5 microns. The goal of a K=+16 sky survey using this array attached to the Steward Observatory Transit Telescope is clearly within reach. The detector material exhibits high quantum efficiency and low dark currents indicating that its usefulness may extend beyond its use with a CCD readout on groundbased telescopes.

  11. Radio Observations of the Ionosphere From an Imaging Array and a CubeSat

    Science.gov (United States)

    Isham, B.; Gustavsson, B.; Bullett, T. W.; Bergman, J. E. S.; Rincón-Charris, A.; Bruhn, F.; Funk, P.

    2017-12-01

    The ionosphere is a source of many radio emissions in the various low-frequency, medium-frequency, and high-frequency bands (0 to 30 MHz). In addition to natural radio emissions, artificial emissions can be stimulated using high-power radiowave ionospheric modification facilities. Two complementary projects are underway for the purpose of improving our knowledge of the processes of radio emissions from the ionosphere. One project is the Aguadilla radio array, located in northwestern Puerto Rico. The Aguadilla array is intended to produce 2 to 25 MHz radio images of the ionosphere, as well as to perform bistatic radar imaging of the ionosphere over Puerto Rico. The array will consist of multiple antenna elements, each of which is a single active (electromagnetically short) crossed electric dipole. The elements are arranged within a roughly 200 by 300-meter core array, in a semi-random pattern providing an optimal distribution of baseline vectors, with 6-meter minimum spacing to eliminate spacial aliasing. In addition, several elements are arranged in a partial ring around the central core, providing a roughly four times expanded region in u-v space for improved image resolution and quality. Phase is maintained via cabled connections to a central location. A remote array is also being developed, in which phase is maintained between elements by through the use of GPS-disciplined rubidium clocks. The other project involves the GimmeRF radio instrument, designed for 0.3 to 30 MHz vector observation of the radio electric field, and planned for launch in 2020 on a CubeSat. The data rate that can be sustained by GimmeRF far exceeds any available communication strategy. By exploiting fast on-board computing and efficient artificial intelligence (AI) algorithms for analysis and data selection, the usage of the telemetry link can be optimized and value added to the mission. Radio images recorded by the radio array from below the ionosphere can be directly compared with the

  12. Biographical encyclopedia of astronomers

    CERN Document Server

    Trimble, Virginia; Williams, Thomas; Bracher, Katherine; Jarrell, Richard; Marché, Jordan; Palmeri, JoAnn; Green, Daniel

    2014-01-01

    The Biographical Encyclopedia of Astronomers is a unique and valuable resource for historians and astronomers alike. It includes approx. 1850 biographical sketches on astronomers from antiquity to modern times. It is the collective work of 430 authors edited by an editorial board of 8 historians and astronomers. This reference provides biographical information on astronomers and cosmologists by utilizing contemporary historical scholarship. The fully corrected and updated second edition adds approximately 300 biographical sketches. Based on ongoing research and feedback from the community, the new entries will fill gaps and provide expansions. In addition, greater emphasis on Russo phone astronomers and radio astronomers is given. Individual entries vary from 100 to 1500 words, including the likes of the super luminaries such as Newton and Einstein, as well as lesser-known astronomers like Galileo's acolyte, Mario Guiducci.

  13. Distributed Read-out Imaging Device array for astronomical observations in UV/VIS

    NARCIS (Netherlands)

    Hijmering, R.A.

    2009-01-01

    STJ (Superconducting Tunneling Junctions) are being developed as spectro-photometers in wavelengths ranging from the NIR to X-rays. 10x12 arrays of STJs have already been successfully used as optical imaging spectrometers with the S-Cam 3, on the William Hershel Telescope on La Palma and on the

  14. High-energy sources at low radio frequency: the Murchison Widefield Array view of Fermi blazars

    International Nuclear Information System (INIS)

    Giroletti, M.; Massaro, F.; D’Abrusco, R.; Lico, R.; Burlon, D.

    2016-01-01

    Low-frequency radio arrays are opening a new window for the study of the sky, both to study new phenomena and to better characterize known source classes. Being flat-spectrum sources, blazars are so far poorly studied at low radio frequencies. In this paper, we characterize the spectral properties of the blazar population at low radio frequency, compare the radio and high-energy properties of the gamma-ray blazar population, and search for radio counterparts of unidentified gamma-ray sources. We cross-correlated the 6100 deg"2 Murchison Widefield Array Commissioning Survey catalogue with the Roma blazar catalogue, the third catalogue of active galactic nuclei detected by Fermi-LAT, and the unidentified members of the entire third catalogue of gamma-ray sources detected by Fermi-LAT. When available, we also added high-frequency radio data from the Australia Telescope 20 GHz catalogue. We find low-frequency counterparts for 186 out of 517 (36%) blazars, 79 out of 174 (45%) gamma-ray blazars, and 8 out of 73 (11%) gamma-ray blazar candidates. The mean low-frequency (120–180 MHz) blazar spectral index is (α_l_o_w) = 0.57 ± 0.02: blazar spectra are flatter than the rest of the population of low-frequency sources, but are steeper than at ~GHz frequencies. Low-frequency radio flux density and gamma-ray energy flux display a mildly significant and broadly scattered correlation. Ten unidentified gamma-ray sources have a (probably fortuitous) positional match with low radio frequency sources. Low-frequency radio astronomy provides important information about sources with a flat radio spectrum and high energy. However, the relatively low sensitivity of the present surveys still misses a significant fraction of these objects. Finally, upcoming deeper surveys, such as the GaLactic and Extragalactic All-Sky MWA (GLEAM) survey, will provide further insight into this population.

  15. Development of the radio astronomical method of cosmic particle detection for extremely high-energy cosmic ray physics and neutrino astronomy

    Directory of Open Access Journals (Sweden)

    Zheleznykh Igor

    2017-01-01

    Full Text Available The proposal to use ground based radio telescopes for detection of Askaryan radio pulses from particle cascades arising when extremely high-energy (EHE > 1020 eV cosmic rays (including neutrinos interact with the lunar regolith of multi gigaton mass was made at the end of 1980s in the framework of the Russian (Soviet DUMAND Program. During more than a quarter of century a number of lunar experiments were carried out mainly in the 1–3 GHz frequency range using the large radio telescopes of Australia, USA, Russia and other countries but these experiments only put upper limits to the EHE cosmic rays fluxes. For this reason, it would be of great interest to search for nanosecond radio pulses from the Moon in a wider interval of frequencies (including lower ones of 100–350 MHz with larger radio detectors – for example the giant radio telescope SKA (Square Kilometer Array which is constructed in Australia, New Zealand and South Africa. In this paper possibilities are discussed to use one of the most sensitive meter-wavelength (∼ 110 MHz Large Phased Array (LPA of 187 × 384 m2 and the wide field of view meter-wavelength array of the Pushchino Radio Astronomy Observatory as prototypes of low frequency radio detectors for lunar experiments. The new scheme for fast simulation of ultrahigh and extremely high-energy cascades in dense media is also suggested. This scheme will be used later for calculations of radio emission of cascades in the lunar regolith with energies up to 1020 eV and higher in the wide frequency band of 0.1− a few GHz.

  16. Subband Adaptive Array for DS-CDMA Mobile Radio

    Directory of Open Access Journals (Sweden)

    Tran Xuan Nam

    2004-01-01

    Full Text Available We propose a novel scheme of subband adaptive array (SBAA for direct-sequence code division multiple access (DS-CDMA. The scheme exploits the spreading code and pilot signal as the reference signal to estimate the propagation channel. Moreover, instead of combining the array outputs at each output tap using a synthesis filter and then despreading them, we despread directly the array outputs at each output tap by the desired user's code to save the synthesis filter. Although its configuration is far different from that of 2D RAKEs, the proposed scheme exhibits relatively equivalent performance of 2D RAKEs while having less computation load due to utilising adaptive signal processing in subbands. Simulation programs are carried out to explore the performance of the scheme and compare its performance with that of the standard 2D RAKE.

  17. Measurement of horizontal air showers with the Auger Engineering Radio Array

    Science.gov (United States)

    Kambeitz, Olga

    2017-03-01

    The Auger Engineering Radio Array (AERA), at the Pierre Auger Observatory in Argentina, measures the radio emission of extensive air showers in the 30-80 MHz frequency range. AERA consists of more than 150 antenna stations distributed over 17 km2. Together with the Auger surface detector, the fluorescence detector and the underground muon detector (AMIGA), AERA is able to measure cosmic rays with energies above 1017 eV in a hybrid detection mode. AERA is optimized for the detection of air showers up to 60° zenith angle, however, using the reconstruction of horizontal air showers with the Auger surface array, very inclined showers can also be measured. In this contribution an analysis of the AERA data in the zenith angle range from 62° to 80° will be presented. CoREAS simulations predict radio emission footprints of several km2 for horizontal air showers, which are now confirmed by AERA measurements. This can lead to radio-based composition measurements and energy determination of horizontal showers in the future and the radio detection of neutrino induced showers is possible.

  18. SURVEYING THE DYNAMIC RADIO SKY WITH THE LONG WAVELENGTH DEMONSTRATOR ARRAY

    International Nuclear Information System (INIS)

    Lazio, T. Joseph W.; Clarke, Tracy E.; Lane, W. M.; Gross, C.; Kassim, N. E.; Hicks, B.; Polisensky, E.; Stewart, K.; Ray, P. S.; Wood, D.; York, J. A.; Kerkhoff, A.; Dalal, N. Paravastu; Cohen, A. S.; Erickson, W. C.

    2010-01-01

    This paper presents a search for radio transients at a frequency of 73.8 MHz (4 m wavelength) using the all-sky imaging capabilities of the Long Wavelength Demonstrator Array (LWDA). The LWDA was a 16-dipole phased array telescope, located on the site of the Very Large Array in New Mexico. The field of view of the individual dipoles was essentially the entire sky, and the number of dipoles was sufficiently small that a simple software correlator could be used to make all-sky images. From 2006 October to 2007 February, we conducted an all-sky transient search program, acquiring a total of 106 hr of data; the time sampling varied, being 5 minutes at the start of the program and improving to 2 minutes by the end of the program. We were able to detect solar flares, and in a special-purpose mode, radio reflections from ionized meteor trails during the 2006 Leonid meteor shower. We detected no transients originating outside of the solar system above a flux density limit of 500 Jy, equivalent to a limit of no more than about 10 -2 events yr -1 deg -2 , having a pulse energy density ∼>1.5 x 10 -20 J m -2 Hz -1 at 73.8 MHz for pulse widths of about 300 s. This event rate is comparable to that determined from previous all-sky transient searches, but at a lower frequency than most previous all-sky searches. We believe that the LWDA illustrates how an all-sky imaging mode could be a useful operational model for low-frequency instruments such as the Low Frequency Array, the Long Wavelength Array station, the low-frequency component of the Square Kilometre Array, and potentially the Lunar Radio Array.

  19. Calibrating the Auger Engineering Radio Array at the Pierre Auger Observatory using an Octocopter

    Energy Technology Data Exchange (ETDEWEB)

    Briechle, Florian; Erdmann, Martin; Krause, Raphael [III. Physikalisches Institut A, RWTH Aachen University (Germany)

    2016-07-01

    With the Auger Engineering Radio Array (AERA) at the Pierre Auger Observatory radio emission of extensive air showers induced by ultra high energy cosmic rays is observed. Characteristics of the primary cosmic ray, e.g., arrival direction, mass or energy, can be measured this way. To produce high quality data, the detector needs to be well understood and calibrated. A useful tool for calibration campaigns is an octocopter. With it, a calibration source can be placed above the array, which makes this a very flexible method useful for different types of calibrations. Special focus is put on the position reconstruction and the position accuracy of the octocopter during the calibration flights. A new optical method using two cameras for these position reconstructions is presented. Results of a measurement campaign in spring 2015 are presented. In this campaign, the sensitivity of the AERA stations as well as timing characteristics were measured. The results of the sensitivity measurement are compared to simulations.

  20. Design, modeling and testing of the Askaryan Radio Array South Pole autonomous renewable power stations

    Energy Technology Data Exchange (ETDEWEB)

    Besson, D.Z., E-mail: zedlam@ku.edu [Department of Physics and Astronomy, University of Kansas, 1082 Malott Hall, 1251 Wescoe Hall Drive, Lawrence, KS 66045-7582 (United States); Moscow Engineering and Physics Institute, 31 Kashirskaya Highway, Moscow 115409 (Russian Federation); Kennedy, D.M., E-mail: dmkennedy@ku.edu [Department of Physics and Astronomy, University of Kansas, 1082 Malott Hall, 1251 Wescoe Hall Drive, Lawrence, KS 66045-7582 (United States); Ratzlaff, K., E-mail: ratzlaff@ku.edu [Instrumentation Design Laboratory, University of Kansas, 6042 Malott Hall, 1251 Wescoe Hall Drive, Lawrence, KS 66045-7582 (United States); Young, R., E-mail: rwyoung@ku.edu [Instrumentation Design Laboratory, University of Kansas, 6042 Malott Hall, 1251 Wescoe Hall Drive, Lawrence, KS 66045-7582 (United States)

    2014-11-01

    We describe the design, construction and operation of the Askaryan Radio Array (ARA) Autonomous Renewable Power Stations, initially installed at the South Pole in December, 2010 with the goal of providing an independently operating 100 W power source capable of year-round operation in extreme environments. In addition to particle astrophysics applications at the South Pole, such a station can easily be, and has since been, extended to operation elsewhere, as described herein.

  1. Design, modeling and testing of the Askaryan Radio Array South Pole autonomous renewable power stations

    International Nuclear Information System (INIS)

    Besson, D.Z.; Kennedy, D.M.; Ratzlaff, K.; Young, R.

    2014-01-01

    We describe the design, construction and operation of the Askaryan Radio Array (ARA) Autonomous Renewable Power Stations, initially installed at the South Pole in December, 2010 with the goal of providing an independently operating 100 W power source capable of year-round operation in extreme environments. In addition to particle astrophysics applications at the South Pole, such a station can easily be, and has since been, extended to operation elsewhere, as described herein

  2. PROSPECTS FOR THE DETECTION OF FAST RADIO BURSTS WITH THE MURCHISON WIDEFIELD ARRAY

    Energy Technology Data Exchange (ETDEWEB)

    Trott, Cathryn M.; Tingay, Steven J.; Wayth, Randall B., E-mail: cathryn.trott@curtin.edu.au [International Centre for Radio Astronomy Research, Curtin University, Bentley WA 6845 (Australia)

    2013-10-10

    Fast radio bursts (FRBs) are short timescale (<<1 s) astrophysical radio signals, presumed to be a signature of cataclysmic events of extragalactic origin. The discovery of six high-redshift events at ∼1400 MHz from the Parkes radio telescope suggests that FRBs may occur at a high rate across the sky. The Murchison Widefield Array (MWA) operates at low radio frequencies (80-300 MHz) and is expected to detect FRBs due to its large collecting area (∼2500 m{sup 2}) and wide field-of-view (FOV, ∼ 1000 deg{sup 2} at ν = 200 MHz). We compute the expected number of FRB detections for the MWA assuming a source population consistent with the reported detections. Our formalism properly accounts for the frequency-dependence of the antenna primary beam, the MWA system temperature, and unknown spectral index of the source population, for three modes of FRB detection: coherent; incoherent; and fast imaging. We find that the MWA's sensitivity and large FOV combine to provide the expectation of multiple detectable events per week in all modes, potentially making it an excellent high time resolution science instrument. Deviations of the expected number of detections from actual results will provide a strong constraint on the assumptions made for the underlying source population and intervening plasma distribution.

  3. Prospects for the Detection of Fast Radio Bursts with the Murchison Widefield Array

    Science.gov (United States)

    Trott, Cathryn M.; Tingay, Steven J.; Wayth, Randall B.

    2013-10-01

    Fast radio bursts (FRBs) are short timescale (Lt1 s) astrophysical radio signals, presumed to be a signature of cataclysmic events of extragalactic origin. The discovery of six high-redshift events at ~1400 MHz from the Parkes radio telescope suggests that FRBs may occur at a high rate across the sky. The Murchison Widefield Array (MWA) operates at low radio frequencies (80-300 MHz) and is expected to detect FRBs due to its large collecting area (~2500 m2) and wide field-of-view (FOV, ~ 1000 deg2 at ν = 200 MHz). We compute the expected number of FRB detections for the MWA assuming a source population consistent with the reported detections. Our formalism properly accounts for the frequency-dependence of the antenna primary beam, the MWA system temperature, and unknown spectral index of the source population, for three modes of FRB detection: coherent; incoherent; and fast imaging. We find that the MWA's sensitivity and large FOV combine to provide the expectation of multiple detectable events per week in all modes, potentially making it an excellent high time resolution science instrument. Deviations of the expected number of detections from actual results will provide a strong constraint on the assumptions made for the underlying source population and intervening plasma distribution.

  4. Observations of inner plasmasphere irregularities with a satellite-beacon radio-interferometer array

    International Nuclear Information System (INIS)

    Jacobson, A.R.; Hoogeveen, G.; Carlos, R.C.; Wu, G.; Fejer, B.G.; Kelley, M.C.

    1996-01-01

    A radio-interferometer array illuminated by 136-MHz beacons of several geosynchronous satellites has been used to study small (≥10 13 m -2 ) transient disturbances in the total electron content along the lines of sight to the satellites. High-frequency (f>3 mHz) electron content oscillations are persistently observed, particularly during night and particularly during geomagnetically disturbed periods. The oscillations move across the array plane at speeds in the range 200 endash 2000 m/s, with propagation azimuths that are strongly peaked in lobes toward the western half-plane. Detailed analysis of this azimuth behavior, involving comparison between observations on various satellite positions, indicates compellingly that the phase oscillations originate in radio refraction due to geomagnetically aligned plasma density perturbations in the inner plasmasphere. The motion of the phase perturbations across the array plane is caused by EXB drift of the plasma medium in which the irregularities are embedded. We review the statistics of 2.5 years of around-the-clock data on the local time, magnetic disturbance, seasonal, and line-of-sight variations of these observed irregularities. We compare the irregularities close-quote inferred electrodynamic drifts to what is known about midlatitude plasma drift from incoherent scatter. Finally, we show in detail how the observation of these irregularities provides a unique and complementary monitor of inner plasmasphere irregularity incidence and zonal drift.copyright 1996 American Geophysical Union

  5. A technique to detect periodic and non-periodic ultra-rapid flux time variations with standard radio-astronomical data

    Science.gov (United States)

    Borra, Ermanno F.; Romney, Jonathan D.; Trottier, Eric

    2018-06-01

    We demonstrate that extremely rapid and weak periodic and non-periodic signals can easily be detected by using the autocorrelation of intensity as a function of time. We use standard radio-astronomical observations that have artificial periodic and non-periodic signals generated by the electronics of terrestrial origin. The autocorrelation detects weak signals that have small amplitudes because it averages over long integration times. Another advantage is that it allows a direct visualization of the shape of the signals, while it is difficult to see the shape with a Fourier transform. Although Fourier transforms can also detect periodic signals, a novelty of this work is that we demonstrate another major advantage of the autocorrelation, that it can detect non-periodic signals while the Fourier transform cannot. Another major novelty of our work is that we use electric fields taken in a standard format with standard instrumentation at a radio observatory and therefore no specialized instrumentation is needed. Because the electric fields are sampled every 15.625 ns, they therefore allow detection of very rapid time variations. Notwithstanding the long integration times, the autocorrelation detects very rapid intensity variations as a function of time. The autocorrelation could also detect messages from Extraterrestrial Intelligence as non-periodic signals.

  6. Proposal for Definitive Survey for Fast Radio Bursts at the Allen Telescope Array

    Science.gov (United States)

    Harp, Gerald; Tarter, J. C.; Welch, W. J.; Allen Telescope Array Team

    2014-01-01

    The Allen Telescope Array, a 42-dish radio interferometer in Northern California is now being upgraded with new, more sensitive receivers covering 0.9-18 GHz continuously. Leveraging this frequency coverage and wide field of view, the ATA is a unique and ideal instrument for the discovery and characterization of fast radio bursts (FRBs, discovered at Parkes and Arecibo) and other short-time domain radio phenomena. The field of view (nearly 10 sq. deg. at 1 GHz) allows for a rapid search of 3π steradians with many lookbacks over a period of 2.5 years. The instantaneous wide-frequency range of the upgraded ATA receivers allows sensitive observations at 4 simultaneous frequency ranges (for example, 0.9 - 1.5 GHz, 1.6-2.2 GHz, 2.5-3.1 GHz, and 4.6-5.2 GHz, full Stokes); something not possible at any other major telescope. This enables very accurate dispersion measure and spectral index characterization of ms-timescale bursts (or other time-variable activity) with a localization accuracy ~20" for SNR > 10 (all FRBs discovered to date would meet this criterium). We discuss the new digital processing system required to perform this survey, with a plan to capture ~400 FRB events during the survey period of performance , based on current event-rate estimates of 10^4 events/sky/day.

  7. MURCHISON WIDEFIELD ARRAY LIMITS ON RADIO EMISSION FROM ANTARES NEUTRINO EVENTS

    International Nuclear Information System (INIS)

    Croft, S.; Kaplan, D. L.; Tingay, S. J.; Murphy, T.; Rowlinson, A.; Bell, M. E.; Adrián-Martínez, S.; Ardid, M.; Ageron, M.; Aubert, J.-J.; Albert, A.; André, M.; Anton, G.; Avgitas, T.; Baret, B.

    2016-01-01

    We present a search, using the Murchison Widefield Array (MWA), for electromagnetic (EM) counterparts to two candidate high-energy neutrino events detected by the ANTARES neutrino telescope in 2013 November and 2014 March. These events were selected by ANTARES because they are consistent, within 0.°4, with the locations of galaxies within 20 Mpc of Earth. Using MWA archival data at frequencies between 118 and 182 MHz, taken ∼20 days prior to, at the same time as, and up to a year after the neutrino triggers, we look for transient or strongly variable radio sources that are consistent with the neutrino positions. No such counterparts are detected, and we set a 5σ upper limit for low-frequency radio emission of ∼10 37 erg s −1 for progenitors at 20 Mpc. If the neutrino sources are instead not in nearby galaxies, but originate in binary neutron star coalescences, our limits place the progenitors at z ≳ 0.2. While it is possible, due to the high background from atmospheric neutrinos, that neither event is astrophysical, the MWA observations are nevertheless among the first to follow up neutrino candidates in the radio, and illustrate the promise of wide-field instruments like MWA for detecting EM counterparts to such events

  8. MURCHISON WIDEFIELD ARRAY LIMITS ON RADIO EMISSION FROM ANTARES NEUTRINO EVENTS

    Energy Technology Data Exchange (ETDEWEB)

    Croft, S. [University of California, Berkeley, Astronomy Department, 501 Campbell Hall #3411, Berkeley, CA 94720 (United States); Kaplan, D. L. [Department of Physics, University of Wisconsin-Milwaukee, 1900 East Kenwood Boulevard, Milwaukee, WI 53211 (United States); Tingay, S. J. [International Centre for Radio Astronomy Research, Curtin University, Bentley, WA 6102 (Australia); Murphy, T.; Rowlinson, A. [ARC Centre of Excellence for All-sky Astrophysics (CAASTRO) (Australia); Bell, M. E. [CSIRO Australia Telescope National Facility, P.O. Box 76, Epping, NSW 1710 (Australia); Adrián-Martínez, S.; Ardid, M. [Institut d’Investigació per a la Gestió Integrada de les Zones Costaneres (IGIC)—Universitat Politècnica de València. C/ Paranimf 1, E-46730 Gandia (Spain); Ageron, M.; Aubert, J.-J. [Aix Marseille Université, CNRS/IN2P3, CPPM UMR 7346, F-13288, Marseille (France); Albert, A. [GRPHE—Université de Haute Alsace—Institut universitaire de technologie de Colmar, 34 rue du Grillenbreit BP 50568-68008 Colmar (France); André, M. [Technical University of Catalonia, Laboratory of Applied Bioacoustics, Rambla Exposició, E-08800 Vilanova i la Geltrú, Barcelona (Spain); Anton, G. [Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen Centre for Astroparticle Physics, Erwin-Rommel-Str. 1, D-91058 Erlangen (Germany); Avgitas, T.; Baret, B. [APC, Université Paris Diderot, CNRS/IN2P3, CEA/IRFU, Observatoire de Paris, Sorbonne Paris Cité, F-75205 Paris (France); Collaboration: for the MWA Collaboration; for the ANTARES Collaboration; for the TAROT Collaboration; for the ROTSE Collaboration; and others

    2016-04-01

    We present a search, using the Murchison Widefield Array (MWA), for electromagnetic (EM) counterparts to two candidate high-energy neutrino events detected by the ANTARES neutrino telescope in 2013 November and 2014 March. These events were selected by ANTARES because they are consistent, within 0.°4, with the locations of galaxies within 20 Mpc of Earth. Using MWA archival data at frequencies between 118 and 182 MHz, taken ∼20 days prior to, at the same time as, and up to a year after the neutrino triggers, we look for transient or strongly variable radio sources that are consistent with the neutrino positions. No such counterparts are detected, and we set a 5σ upper limit for low-frequency radio emission of ∼10{sup 37} erg s{sup −1} for progenitors at 20 Mpc. If the neutrino sources are instead not in nearby galaxies, but originate in binary neutron star coalescences, our limits place the progenitors at z ≳ 0.2. While it is possible, due to the high background from atmospheric neutrinos, that neither event is astrophysical, the MWA observations are nevertheless among the first to follow up neutrino candidates in the radio, and illustrate the promise of wide-field instruments like MWA for detecting EM counterparts to such events.

  9. Medicina array demonstrator: calibration and radiation pattern characterization using a UAV-mounted radio-frequency source

    Science.gov (United States)

    Pupillo, G.; Naldi, G.; Bianchi, G.; Mattana, A.; Monari, J.; Perini, F.; Poloni, M.; Schiaffino, M.; Bolli, P.; Lingua, A.; Aicardi, I.; Bendea, H.; Maschio, P.; Piras, M.; Virone, G.; Paonessa, F.; Farooqui, Z.; Tibaldi, A.; Addamo, G.; Peverini, O. A.; Tascone, R.; Wijnholds, S. J.

    2015-06-01

    One of the most challenging aspects of the new-generation Low-Frequency Aperture Array (LFAA) radio telescopes is instrument calibration. The operational LOw-Frequency ARray (LOFAR) instrument and the future LFAA element of the Square Kilometre Array (SKA) require advanced calibration techniques to reach the expected outstanding performance. In this framework, a small array, called Medicina Array Demonstrator (MAD), has been designed and installed in Italy to provide a test bench for antenna characterization and calibration techniques based on a flying artificial test source. A radio-frequency tone is transmitted through a dipole antenna mounted on a micro Unmanned Aerial Vehicle (UAV) (hexacopter) and received by each element of the array. A modern digital FPGA-based back-end is responsible for both data-acquisition and data-reduction. A simple amplitude and phase equalization algorithm is exploited for array calibration owing to the high stability and accuracy of the developed artificial test source. Both the measured embedded element patterns and calibrated array patterns are found to be in good agreement with the simulated data. The successful measurement campaign has demonstrated that a UAV-mounted test source provides a means to accurately validate and calibrate the full-polarized response of an antenna/array in operating conditions, including consequently effects like mutual coupling between the array elements and contribution of the environment to the antenna patterns. A similar system can therefore find a future application in the SKA-LFAA context.

  10. FIRST SPECTROSCOPIC IMAGING OBSERVATIONS OF THE SUN AT LOW RADIO FREQUENCIES WITH THE MURCHISON WIDEFIELD ARRAY PROTOTYPE

    International Nuclear Information System (INIS)

    Oberoi, Divya; Matthews, Lynn D.; Lonsdale, Colin J.; Benkevitch, Leonid; Cairns, Iver H.; Lobzin, Vasili; Emrich, David; Wayth, Randall B.; Arcus, Wayne; Morgan, Edward H.; Williams, Christopher; Prabu, T.; Vedantham, Harish; Williams, Andrew; White, Stephen M.; Allen, G.; Barnes, David; Bernardi, Gianni; Bowman, Judd D.; Briggs, Frank H.

    2011-01-01

    We present the first spectroscopic images of solar radio transients from the prototype for the Murchison Widefield Array, observed on 2010 March 27. Our observations span the instantaneous frequency band 170.9- 201.6 MHz. Though our observing period is characterized as a period of 'low' to 'medium' activity, one broadband emission feature and numerous short-lived, narrowband, non-thermal emission features are evident. Our data represent a significant advance in low radio frequency solar imaging, enabling us to follow the spatial, spectral, and temporal evolution of events simultaneously and in unprecedented detail. The rich variety of features seen here reaffirms the coronal diagnostic capability of low radio frequency emission and provides an early glimpse of the nature of radio observations that will become available as the next generation of low-frequency radio interferometers come online over the next few years.

  11. Nullspace MUSIC and Improved Radio Frequency Emitter Geolocation from a Mobile Antenna Array

    Science.gov (United States)

    Kintz, Andrew L.

    This work advances state-of-the-art Radio Frequency (RF) emitter geolocation from an airborne or spaceborne antenna array. With an antenna array, geolocation is based on Direction of Arrival (DOA) estimation algorithms such as MUSIC. The MUSIC algorithm applies to arbitrary arrays of polarization sensitive antennas and yields high resolution. However, MUSIC fails to obtain its theoretical resolution for simultaneous, closely spaced, co-frequency signals. We propose the novel Nullspace MUSIC algorithm, which outperforms MUSIC and its existing modifications while maintaining MUSIC(apostrophe)s fundamental orthogonality test. Nullspace MUSIC applies a divide-and-conquer approach and estimates a single DOA at a time. Additionally, an antenna array on an aircraft cannot be perfectly calibrated. RF waves are blocked, reflected, and scattered in a time-varying fashion by the platform around the antenna array. Consequently, full-wave electromagnetics simulations or demanding measurements of the entire platform cannot eliminate the mismatch between the true, in-situ antenna patterns and the antenna patterns that are available for DOA estimation (the antenna array manifold). Platform-induced manifold mismatch severely degrades MUSIC(apostrophe)s resolution and accuracy. We show that Nullspace MUSIC improves DOA accuracy for well separated signals that are incident on an airborne antenna array. Conventionally, geolocation from a mobile platform draws Lines of Bearing (LOB) from the antenna array along the DOAs to find the locations where the DOAs intersect with the ground. However, averaging the LOBs in the global coordinate system yields large errors due to geometric dilution of precision. Since averaging positions fails, a single emitter is typically located by finding the position on the ground that yields the Minimum Apparent Angular Error (MAAE) for the DOA estimates over a flight. We extend the MAAE approach to cluster LOBs from multiple emitters. MAAE clustering

  12. Frontiers of Radio Astronomy in the 2020s: The Next Generation Very Large Array

    Science.gov (United States)

    Murphy, Eric Joseph; ngVLA Project Office, ngVLA Science and Technical Advisory Councils, ngVLA Science Working Groups

    2018-01-01

    This talk will describe the current community-driven science goals, design, and planning status of a future large centimeter radio array: the ‘Next Generation Very Large Array’ (ngVLA). The ngVLA is being developed to observe at wavelengths between ALMA at submm wavelengths, and the future SKA-1 at few centimeter and longer wavelengths, opening a new window on the Universe through ultra-sensitive imaging of thermal line and continuum emission down to milliarcsecond resolution, and unprecedented broad band continuum polarimetric imaging of non-thermal processes. The current design for the array includes 10x more effective collecting area and 10x higher spatial resolution than the current JVLA or ALMA, carefully optimized for operation in the frequency range 10GHz to 50GHz, while still delivering world-leading sensitivity over the entire 1.2GHz to 116 GHz spectrum.With this array, new frontiers in modern astronomy can be reached, including direct imaging and chemical analysis of planet formation in the terrestrial-zone of nearby stars, studies of dust-obscured star formation and the cosmic baryon cycle down to pc-scales in the local Universe, and detailed imaging of molecular gas and galaxy formation into the epoch of reionization. Novel techniques for exploring temporal phenomena on timescales from milliseconds to years will also be implemented. The ngVLA will be situated in the desert southwest of the United States, centered on the current JVLA infrastructure, with multiple antennas anticipated in states/regions adjacent to NM, and in northern Mexico.A recently formed Project Office is working closely with the U.S. and international research community to design the array, and plan its construction beginning mid next decade. Recent significant funding for design and development brought forward by the NSF will enable detailed science case development and technology prototyping/risk reduction before the next U.S astronomy Decadal Survey.

  13. OBSERVATIONS OF ROTATING RADIO TRANSIENTS WITH THE FIRST STATION OF THE LONG WAVELENGTH ARRAY

    Energy Technology Data Exchange (ETDEWEB)

    Taylor, G. B.; Stovall, K.; McCrackan, M.; Dowell, J.; Schinzel, F. K. [Department of Physics and Astronomy, University of New Mexico, Albuquerque NM, 87131 (United States); McLaughlin, M. A.; Miller, R. [Department of Physics and Astronomy, West Virginia University, Morgantown, WV 26506-6315 (United States); Karako-Argaman, C. [Department of Physics, McGill University, 3600 University Street, Montreal, QC H3A 2T8 (Canada)

    2016-11-10

    Rotating radio transients (RRATs) are a subclass of pulsars first identified in 2006 that are detected only in searches for single pulses and not through their time averaged emission. Here, we present the results of observations of 19 RRATs using the first station of the Long Wavelength Array (LWA1) at frequencies between 30 and 88 MHz. The RRATs observed here were first detected in higher frequency pulsar surveys. Of the 19 RRATs observed, two sources were detected and their dispersion measures, periods, pulse profiles, and flux densities are reported and compared to previous higher frequency measurements. We find a low detection rate (11%), which could be a combination of the lower sensitivity of LWA1 compared to higher frequency telescopes, and the result of scattering by the interstellar medium or a spectral turnover.

  14. Development of a radio-detection array for the observation of UHE neutrino-induced showers

    Energy Technology Data Exchange (ETDEWEB)

    Ardouin, Daniel [SUBATECH, IN2P3-CNRS, University of Nantes, E. Mines Nantes, Nantes (France)], E-mail: Daniel.ardouin@univ-nantes.fr; Charrier, Didier; Lautridou, Pascal [SUBATECH, IN2P3-CNRS, University of Nantes, E. Mines Nantes, Nantes (France); Martineau-Huynh, Olivier [LPNHE, IN2P3-CNRS, University of Paris VI, Paris (France); Ravel, Olivier [SUBATECH, IN2P3-CNRS, University of Nantes, E. Mines Nantes, Nantes (France); Wu Xiangping; Zhao Meng [NAOC, Beijing (China)

    2009-06-01

    The recent demonstration by the CODALEMA collaboration of the ability of the radio-detection technique for the characterization of ultra-high-energy cosmic-rays (UHECR) calls for the use of this powerful method for the observation of UHE neutrinos. For this purpose, an adaptation of the already existing 21CM-Array (CMA) in China, is presently under achievement. In an exceptionally low electromagnetic noise level, 10160 log-periodic 50-200 MHz antennas sit along two high-altitude valleys, surrounded by mountain chains. This layout results in 30-60 km effective rock thicknesses for {nu} interactions with low incidence trajectories along the direction of two 4-6 km baselines. We will present first in-situ radio measurements demonstrating that this environment shows particularly favourable physical conditions for the observation of electromagnetic decay signals of {tau}'s leptons originating from the interaction of 10{sup 17-20} eV {nu}{sub {tau}} neutrinos.

  15. Development of a radio-detection array for the observation of UHE neutrino induced showers

    Energy Technology Data Exchange (ETDEWEB)

    Ardouin, D.; Charrier, D.; Lautridou, P.; Ravel, O. [Nantes Univ., E.Mines, SUBATECH, IN2P3-CNRS, 44 (France); Martineau-Huynh, O. [Paris-6 Univ., LPNHE, IN2P3-CNRS, 75 (France). Lab. de Physique Nucleaire et de Hautes Energies; Xiang-Ping, Wu; Meng, Zhao [NAOC, Beijing (China)

    2008-07-01

    The recent demonstration by the CODALEMA Collaboration of the ability of the radio-detection technique for the characterization of ultra-high energy cosmic-rays (UHECR) calls for the use of this powerful method for the observation of UHE neutrinos. For this purpose, an adaptation of the already existing 21CM-Array in China, is presently under achievement. In an exceptionally low electromagnetic noise level, 10160 log-periodic 50-200 MHz antennas sit along two high altitude valleys, surrounded by mountain chains. This lay-out results in 30-60 km effective rock thicknesses for {nu} interactions with low incidence trajectories along the direction of two 4-6 km baselines. We will present first in-situ radio measurements demonstrating that this environment shows particularly favourable physical conditions for the observation of electromagnetic decay signals of {tau}'s leptons originating from the interaction of 10{sup 17-20} eV {nu}{sub {tau}} neutrinos. (authors)

  16. Radio Astronomy in Malaysia: Current Status and Outreach Activities

    Science.gov (United States)

    Hashim, N.; Abidin, Z. Z.; Ibrahim, U. F. S. U.; Umar, R.; Hassan, M. S. R.; Rosli, Z.; Hamidi, Z. S.; Ibrahim, Z. A.

    2011-12-01

    In this paper, we will present the current status of radio astronomical research and outreach in Malaysia. We will also present a short history of our research group, which is currently the only radio astronomical facility in Malaysia. Our group is called the Radio Cosmology Research Lab and was established in 2005 by Dr Zamri Zainal Abidin and Prof Dr Zainol Abidin Ibrahim. We will discuss the future plans for this group including our keen interest in being part of a more global network of radio astronomers. We are already an active member of the South-East Asia Astronomy Network (SEAAN) and aims to have a radio astronomical facility in order to join the Global Very Long Baseline Interferometer (VLBI) as well becoming a research hub for the future Square Kilometer Array (SKA) project. We will also present some of the scientific goals of our group including providing a platform for radio astronomers to be able to do observations of weak and high red-shifted radio objects such as galaxy clusters and supernovae.

  17. Radio Channel Sounding Using a Circular Horn Antenna Array in the Horizontal Plane in the 2.3 GHz Band

    DEFF Research Database (Denmark)

    Yamamoto, Atsushi; Sakata, Tsutomu; Ogawa, Koichi

    2012-01-01

    This paper presents results from an outdoor radio propagation experiment at 2.35 GHz using a channel sounder and a spherical horn antenna array. The propagation test was performed in Aalborg city in Denmark. Comparing the ray-tracing results and the results obtained with the proposed method...... on the measured data shows a good match in both the spatial and time domains....

  18. Research on Wide-field Imaging Technologies for Low-frequency Radio Array

    Science.gov (United States)

    Lao, B. Q.; An, T.; Chen, X.; Wu, X. C.; Lu, Y.

    2017-09-01

    Wide-field imaging of low-frequency radio telescopes are subject to a number of difficult problems. One particularly pernicious problem is the non-coplanar baseline effect. It will lead to distortion of the final image when the phase of w direction called w-term is ignored. The image degradation effects are amplified for telescopes with the wide field of view. This paper summarizes and analyzes several w-term correction methods and their technical principles. Their advantages and disadvantages have been analyzed after comparing their computational cost and computational complexity. We conduct simulations with two of these methods, faceting and w-projection, based on the configuration of the first-phase Square Kilometre Array (SKA) low frequency array. The resulted images are also compared with the two-dimensional Fourier transform method. The results show that image quality and correctness derived from both faceting and w-projection are better than the two-dimensional Fourier transform method in wide-field imaging. The image quality and run time affected by the number of facets and w steps have been evaluated. The results indicate that the number of facets and w steps must be reasonable. Finally, we analyze the effect of data size on the run time of faceting and w-projection. The results show that faceting and w-projection need to be optimized before the massive amounts of data processing. The research of the present paper initiates the analysis of wide-field imaging techniques and their application in the existing and future low-frequency array, and fosters the application and promotion to much broader fields.

  19. VERY LONG BASELINE ARRAY IMAGING OF PARSEC-SCALE RADIO EMISSIONS IN NEARBY RADIO-QUIET NARROW-LINE SEYFERT 1 GALAXIES

    Energy Technology Data Exchange (ETDEWEB)

    Doi, Akihiro [The Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency, 3-1-1 Yoshinodai, Chuou-ku, Sagamihara, Kanagawa 252-5210 (Japan); Asada, Keiichi; Inoue, Makoto [Academia Sinica Institute of Astronomy and Astrophysics, P.O. Box 23-141, Taipei 10617, Taiwan (China); Fujisawa, Kenta [The Research Institute of Time Studies, Yamaguchi University, 1677-1 Yoshida, Yamaguchi, Yamaguchi 753-8511 (Japan); Nagai, Hiroshi; Hagiwara, Yoshiaki [National Astronomical Observatory, 2-21-1 Osawa, Mitaka, Tokyo 181-8588 (Japan); Wajima, Kiyoaki, E-mail: akihiro.doi@vsop.isas.jaxa.jp [Shanghai Astronomical Observatory, Chinese Academy of Sciences, Shanghai 200030 (China)

    2013-03-01

    We conducted Very Long Baseline Array (VLBA) observations of seven nearby narrow-line Seyfert 1 (NLS1) galaxies at 1.7 GHz ({lambda}18 cm) with milliarcsecond resolution. This is the first systematic very long baseline interferometry study focusing on the central parsec-scale regions of radio-quiet NLS1s. Five of the seven were detected at a brightness temperature of {approx}> 5 Multiplication-Sign 10{sup 6} K and contain radio cores with high brightness temperatures of >6 Multiplication-Sign 10{sup 7} K, indicating a nonthermal process driven by jet-producing central engines as in radio-loud NLS1s and other active galactic nucleus classes. VLBA images of MRK 1239, MRK 705, and MRK 766 exhibit parsec-scale jets with clear linear structures. A large portion of the radio power comes from diffuse emission components that are distributed within the nuclear regions ({approx}< 300 pc), which is a common characteristic throughout the observed NLS1s. Jet kinetic powers limited by the Eddington limit may be insufficient to allow the jets to escape to kiloparsec scales for these radio-quiet NLS1s with low-mass black holes of {approx}< 10{sup 7} M {sub Sun }.

  20. Image Reconstruction in Radio Astronomy with Non-Coplanar Synthesis Arrays

    Science.gov (United States)

    Goodrick, L.

    2015-03-01

    Traditional radio astronomy imaging techniques assume that the interferometric array is coplanar, with a small field of view, and that the two-dimensional Fourier relationship between brightness and visibility remains valid, allowing the Fast Fourier Transform to be used. In practice, to acquire more accurate data, the non-coplanar baseline effects need to be incorporated, as small height variations in the array plane introduces the w spatial frequency component. This component adds an additional phase shift to the incoming signals. There are two approaches to account for the non-coplanar baseline effects: either the full three-dimensional brightness and visibility model can be used to reconstruct an image, or the non-coplanar effects can be removed, reducing the three dimensional relationship to that of the two-dimensional one. This thesis describes and implements the w-projection and w-stacking algorithms. The aim of these algorithms is to account for the phase error introduced by non-coplanar synthesis arrays configurations, making the recovered visibilities more true to the actual brightness distribution model. This is done by reducing the 3D visibilities to a 2D visibility model. The algorithms also have the added benefit of wide-field imaging, although w-stacking supports a wider field of view at the cost of more FFT bin support. For w-projection, the w-term is accounted for in the visibility domain by convolving it out of the problem with a convolution kernel, allowing the use of the two-dimensional Fast Fourier Transform. Similarly, the w-Stacking algorithm applies a phase correction in the image domain to image layers to produce an intensity model that accounts for the non-coplanar baseline effects. This project considers the KAT7 array for simulation and analysis of the limitations and advantages of both the algorithms. Additionally, a variant of the Högbom CLEAN algorithm was used which employs contour trimming for extended source emission flagging. The

  1. EXPANDED VERY LARGE ARRAY OBSERVATIONS OF THE RADIO EVOLUTION OF SN 2011dh

    Energy Technology Data Exchange (ETDEWEB)

    Krauss, M. I.; Chomiuk, L.; Brunthaler, A.; Rupen, M. [National Radio Astronomy Observatory, Socorro, NM 87801 (United States); Soderberg, A. M.; Zauderer, B. A. [Harvard-Smithsonian Center for Astrophysics, 60 Garden St., Cambridge, MA 02138 (United States); Bietenholz, M. F. [Department of Physics and Astronomy, York University, Toronto, M3J 1P3, Ontario (Canada); Chevalier, R. A. [Astronomy Department, University of Virginia, Charlottesville, VA 22904 (United States); Fransson, C. [Department of Astronomy, The Oskar Klein Centre, Stockholm University, 106 91 Stockholm (Sweden)

    2012-05-10

    We report on Expanded Very Large Array observations of the Type IIb supernova 2011dh, performed over the first 100 days of its evolution and spanning 1-40 GHz in frequency. The radio emission is well described by the self-similar propagation of a spherical shockwave, generated as the supernova ejecta interact with the local circumstellar environment. Modeling this emission with a standard synchrotron self-absorption (SSA) model gives an average expansion velocity of v Almost-Equal-To 0.1c, supporting the classification of the progenitor as a compact star (R{sub *} Almost-Equal-To 10{sup 11} cm). We find that the circumstellar density is consistent with a {rho}{proportional_to}r{sup -2} profile. We determine that the progenitor shed mass at a constant rate of Almost-Equal-To 3 Multiplication-Sign 10{sup -5} M{sub Sun} yr{sup -1}, assuming a wind velocity of 1000 km s{sup -1} (values appropriate for a Wolf-Rayet star), or Almost-Equal-To 7 Multiplication-Sign 10{sup -7} M{sub Sun} yr{sup -1} assuming 20 km s{sup -1} (appropriate for a yellow supergiant [YSG] star). Both values of the mass-loss rate assume a converted fraction of kinetic to magnetic energy density of {epsilon}{sub B} = 0.1. Although optical imaging shows the presence of a YSG, the rapid optical evolution and fast expansion argue that the progenitor is a more compact star-perhaps a companion to the YSG. Furthermore, the excellent agreement of the radio properties of SN 2011dh with the SSA model implies that any YSG companion is likely in a wide, non-interacting orbit.

  2. Reliability-centered maintenance for ground-based large optical telescopes and radio antenna arrays

    Science.gov (United States)

    Marchiori, G.; Formentin, F.; Rampini, F.

    2014-07-01

    In the last years, EIE GROUP has been more and more involved in large optical telescopes and radio antennas array projects. In this frame, the paper describes a fundamental aspect of the Logistic Support Analysis (LSA) process, that is the application of the Reliability-Centered Maintenance (RCM) methodology for the generation of maintenance plans for ground-based large optical telescopes and radio antennas arrays. This helps maintenance engineers to make sure that the telescopes continue to work properly, doing what their users require them to do in their present operating conditions. The main objective of the RCM process is to establish the complete maintenance regime, with the safe minimum required maintenance, carried out without any risk to personnel, telescope and subsystems. At the same time, a correct application of the RCM allows to increase the cost effectiveness, telescope uptime and items availability, and to provide greater understanding of the level of risk that the organization is managing. At the same time, engineers shall make a great effort since the initial phase of the project to obtain a telescope requiring easy maintenance activities and simple replacement of the major assemblies, taking special care on the accesses design and items location, implementation and design of special lifting equipment and handling devices for the heavy items. This maintenance engineering framework is based on seven points, which lead to the main steps of the RCM program. The initial steps of the RCM process consist of: system selection and data collection (MTBF, MTTR, etc.), definition of system boundaries and operating context, telescope description with the use of functional block diagrams, and the running of a FMECA to address the dominant causes of equipment failure and to lay down the Critical Items List. In the second part of the process the RCM logic is applied, which helps to determine the appropriate maintenance tasks for each identified failure mode. Once

  3. Preliminary Data Pipeline for SunRISE: Assessing the Performance of Space Based Radio Arrays

    Science.gov (United States)

    Hegedus, A. M.; Kasper, J. C.; Lazio, J.; Amiri, N.; Stuart, J.

    2017-12-01

    The Sun Radio Interferometer Space Experiment (SunRISE) is a NASA Heliophysics Explorer Mission of Opportunity that was recently awarded phase A funding. SunRISE's main science goals are to localize the source of particle acceleration in coronal mass ejections to 1/4th of their width, and trace the path of electron beams along magnetic field lines out to 20 solar radii. These processes generate cascading Type II and III bursts that have ever only been detected in low frequencies with single spacecraft antenna. These bursts emit below the ionospheric cutoff of 10 MHz past 2 solar radii, so a synthetic aperture made from multiple space antennae is needed to pinpoint the origin of these bursts. In this work, we create an end to end simulation of the data processing pipeline of SunRISE, which uses 6 small satellites to do this localization. One of the main inputs of the simulation is a ground truth of what we want the array to image. We idealized this as an elliptical Gaussian offset from the sun, which previous modeling suggests is a good approximation of what SunRISE would see in space. Another input is an orbit file describing the positions of all the spacecraft. The simulated orbit determinations are made with GPS sidelobes and have an error associated with the recovered positions. From there we compute the Fourier coefficients every antenna will see, then apply the correct phase lags and multiply each pair of coefficients to simulate the process of correlation. We compute the projected UVW coordinates and put these along with the correlated visibilities into a CASA MS file. The correlated visibilities are compared to CASA's simulated visibilities at the same UVW coordinates, verifying the accuracy of our method. The visibilities are then subjected to realistic thermal noise, as well as phase noise from uncertainties in the spacecraft position. We employ CASA's CLEAN algorithm to image the data, and CASA's imfit algorithm to estimate the parameters of the imaged

  4. The very-long-baseline array

    International Nuclear Information System (INIS)

    Kellermann, K.I.; Thompson, A.R.

    1988-01-01

    The development of radio technology in World War II opened a completely new window on the universe. When astronomers turned radio antennas to the heavens, they began to find a previously unknown universe of solar and planetary radio bursts, quasars, pulsars, radio galaxies, giant molecular clouds and cosmic masers. Not only do the radio waves reveal a new world of astronomical phenomena but also-because they are much longer than light waves-they are not as severely distorted by atmospheric turbulence or small imperfections in the telescope. About 25 years ago radio astronomers became aware that they could synthesize a resolution equivalent to that of a large aperture by combining data from smaller radio antennas that are widely separated. The effective aperture size would be about equal to the largest separation between the antennas. The technique is called synthesis imaging and is based on the principles of interferometry. Radio astronomers in the U.S. are now building a synthesis radio telescope called the Very-Long-Baseline Array, or VLBA. With 10 antennas sited across the country from the Virgin Islands to Hawaii, it will synthesize a radio antenna 8,000 kilometers across, nearly the diameter of the earth. The VLBA'S angular resolution will be less than a thousandth of an arc-second-about three orders of magnitude better than that of the largest conventional ground-based optical telescopes. Astronomers eagerly await the completion early in the next decade of the VLBA, which is expected, among other things, to give an unprecedentedly clear view into the cores of quasars and galactic nuclei and to reveal details of the processe-thought to be powered by black holes-that drive them

  5. The prospects of pulsar timing with new-generation radio telescopes and the Square Kilometre Array

    Science.gov (United States)

    Stappers, B. W.; Keane, E. F.; Kramer, M.; Possenti, A.; Stairs, I. H.

    2018-05-01

    Pulsars are highly magnetized and rapidly rotating neutron stars. As they spin, the lighthouse-like beam of radio emission from their magnetic poles sweeps across the Earth with a regularity approaching that of the most precise clocks known. This precision combined with the extreme environments in which they are found, often in compact orbits with other neutron stars and white dwarfs, makes them excellent tools for studying gravity. Present and near-future pulsar surveys, especially those using the new generation of telescopes, will find more extreme binary systems and pulsars that are more precise `clocks'. These telescopes will also greatly improve the precision to which we can measure the arrival times of the pulses. The Square Kilometre Array will revolutionize pulsar searches and timing precision. The increased number of sources will reveal rare sources, including possibly a pulsar-black hole binary, which can provide the most stringent tests of strong-field gravity. The improved timing precision will reveal new phenomena and also allow us to make a detection of gravitational waves in the nanohertz frequency regime. It is here where we expect to see the signature of the binary black holes that are formed as galaxies merge throughout cosmological history. This article is part of a discussion meeting issue `The promises of gravitational-wave astronomy'.

  6. Primary Beam and Dish Surface Characterization at the Allen Telescope Array by Radio Holography

    Science.gov (United States)

    Harp, G. R.; Ackermann, R. F.; Nadler, Z. J.; Blair, Samantha K.; Davis, M. M.; Wright, M. C. H.; Forster, J. R.; Deboer, D. R.; Welch, W. J.; Atkinson, Shannon; Backer, D. C.; Backus, P. R.; Barott, William; Bauermeister, Amber; Blitz, Leo; Bock, D. C.-J.; Bower, Geoffrey C.; Bradford, Tucker; Cheng, Calvin; Croft, Steve; Dexter, Matt; Dreher, John; Engargiola, Greg; Fields, E. D.; Heiles, Carl; Helfer, Tamara; Jordan, Jane; Jorgensen, Susan; Kilsdonk, Tom; Gutierrez-Kraybill, Colby; Keating, Garrett; Law, Casey; Lugten, John; MacMahon, D. H. E.; McMahon, Peter; Milgrome, Oren; Siemion, Andrew; Smolek, Ken; Thornton, Douglas; Pierson, Tom; Randall, Karen; Ross, John; Shostak, Seth; Tarter, J. C.; Urry, Lynn; Werthimer, Dan; Williams, Peter K. G.; Whysong, David

    2011-06-01

    The Allen Telescope Array (ATA) is a cm-wave interferometer in California, comprising 42 antenna elements with 6-m diameter dishes. We characterize the antenna optical accuracy using two-antenna interferometry and radio holography. The distortion of each telescope relative to the average is small, with RMS differences of 1% of beam peak value. Holography provides images of dish illumination, characterizing as-built mirror surfaces. Maximal distortions across ~ 2 meter lengths appear to result from mounting stresses or solar radiation. Experimental RMS errors are 0.7 mm at night and 3 mm under worst-case solar illumination. For frequencies 4, 10, and 15 GHz, the nighttime values indicate sensitivity losses of 1, 10 and 20%, respectively. ATA's wide-bandwidth receiver permits observations over a continuous range 0.5-11.2 GHz. We probe the antenna optical gain and beam pattern stability as a function of focus position and observation frequency, concluding that ATA can produce high fidelity images over a decade of simultaneous observation frequencies. We quantify solar heating effects on antenna sensitivity and pointing accuracy. We find that during the day, observations >=5 GHz will suffer some sensitivity loss and it may be necessary to make antenna pointing corrections on a 1-2 hourly basis.

  7. LOFAR tied-array imaging of Type III solar radio bursts

    NARCIS (Netherlands)

    Morosan, D.E.; et al., [Unknown; Hessels, J.W.T.; Markoff, S.

    2014-01-01

    Context. The Sun is an active source of radio emission which is often associated with energetic phenomena such as solar flares and coronal mass ejections (CMEs). At low radio frequencies (<100 MHz), the Sun has not been imaged extensively because of the instrumental limitations of previous radio

  8. LOFAR tied-array imaging of Type III solar radio bursts

    NARCIS (Netherlands)

    Morosan, D.E.; Gallagher, P.T.; Zucca, P.; Fallows, R.; Carley, E.P.; Mann, G.; Bisi, M.M.; Kerdraon, A.; Avruch, I.M.; Bentum, Marinus Jan; Bernardi, G.; Best, P.; Bonafede, A.; Bregman, J.; Breitling, F.

    2014-01-01

    Context: The Sun is an active source of radio emission which is often associated with energetic phenomena such as solar flares and coronal mass ejections (CMEs). At low radio frequencies (<100 MHz), the Sun has not been imaged extensively because of the instrumental limitations of previous radio

  9. SAMSI: An orbiting spatial interferometer for micro-arc second astronomical observations. [Spacecraft Array for Michelson Spatial Interferometry (SAMSI)

    Science.gov (United States)

    Stachnik, R. V.; Gezari, D. Y.

    1985-01-01

    The concept and performance of (SAMSI) Spacecraft Array for Michelson Spatial Interferometry, an orbiting spatial interferometer comprised of three free-flying spacecraft, two collector telescopes and a central mixing station are described. In the one-dimensional interferometry mode orbits exist which provide natural scanning of the baseline. These orbits place extremely small demands on thrusters and fuel consumption. Resolution of 0.00001 arcsecond and magnitude limits of mv = 15 to 20 are achievable in a single orbit. In the imaging mode, SAMSI could synthesize images equivalent to those produced by equal diameter filled apertures in space, making use of the fuel resupply capability of a space station. Simulations indicate that image reconstruction can be performed with milliarcsecond resolution to a visual magnitude 12 in 12 hr of spiral scanning integration time.

  10. Astronomical Cybersketching

    CERN Document Server

    Grego, Peter

    2009-01-01

    Outlines the techniques involved in making observational sketches and more detailed 'scientific' drawings of a wide variety of astronomical subjects using modern digital equipment; primarily PDAs and tablet PCs. This book also discusses about choosing hardware and software

  11. Amateur Planetary Radio Data Archived for Science and Education: Radio Jove

    Science.gov (United States)

    Thieman, J.; Cecconi, B.; Sky, J.; Garcia, L. N.; King, T. A.; Higgins, C. A.; Fung, S. F.

    2015-12-01

    The Radio Jove Project is a hands-on educational activity in which students, teachers, and the general public build simple radio telescopes, usually from a kit, to observe single frequency decameter wavelength radio emissions from Jupiter, the Sun, the galaxy, and the Earth usually with simple dipole antennas. Some of the amateur observers have upgraded their receivers to spectrographs and their antennas have become more sophisticated as well. The data records compare favorably to more sophisticated professional radio telescopes such as the Long Wavelength Array (LWA) and the Nancay Decametric Array. Since these data are often carefully calibrated and recorded around the clock in widely scattered locations they represent a valuable database useful not only to amateur radio astronomers but to the professional science community as well. Some interesting phenomena have been noted in the data that are of interest to the professionals familiar with such records. The continuous monitoring of radio emissions from Jupiter could serve as useful "ground truth" data during the coming Juno mission's radio observations of Jupiter. Radio Jove has long maintained an archive for thousands of Radio Jove observations, but the database was intended for use by the Radio Jove participants only. Now, increased scientific interest in the use of these data has resulted in several proposals to translate the data into a science community data format standard and store the data in professional archives. Progress is being made in translating Radio Jove data to the Common Data Format (CDF) and also in generating new observations in that format as well. Metadata describing the Radio Jove data would follow the Space Physics Archive Search and Extract (SPASE) standard. The proposed archive to be used for long term preservation would be the Planetary Data System (PDS). Data sharing would be achieved through the PDS and the Paris Astronomical Data Centre (PADC) and the Virtual Wave Observatory (VWO

  12. VERY LARGE ARRAY OBSERVATIONS OF DG TAU'S RADIO JET: A HIGHLY COLLIMATED THERMAL OUTFLOW

    Energy Technology Data Exchange (ETDEWEB)

    Lynch, C.; Mutel, R. L.; Gayley, K. G. [Department of Physics and Astronomy, University of Iowa, Iowa City, Iowa 52240 (United States); Guedel, M. [Department of Astrophysics, University of Vienna, A-1180 Vienna (Austria); Ray, T. [Astronomy and Astrophysics Section, Dublin Institute for Advanced Studies, 31 Fitzwilliam Place, Dublin 2 (Ireland); Skinner, S. L. [Center for Astrophysics and Space Astronomy, University of Colorado, Boulder, CO 80309 (United States); Schneider, P. C. [Hamburger Sternwarte, Gojenbergsweg 112, D-21029 Hamburg (Germany)

    2013-03-20

    The active young protostar DG Tau has an extended jet that has been well studied at radio, optical, and X-ray wavelengths. We report sensitive new Very Large Array (VLA) full-polarization observations of the core and jet between 5 GHz and 8 GHz. Our high angular resolution observation at 8 GHz clearly shows an unpolarized inner jet with a size of 42 AU (0.''35) extending along a position angle similar to the optical-X ray outer jet. Using our nearly coeval 2012 VLA observations, we find a spectral index {alpha} = +0.46 {+-} 0.05, which combined with the lack of polarization is consistent with bremsstrahlung (free-free) emission, with no evidence for a non-thermal coronal component. By identifying the end of the radio jet as the optical depth unity surface, and calculating the resulting emission measure, we find that our radio results are in agreement with previous optical line studies of electron density and consequent mass-loss rate. We also detect a weak radio knot at 5 GHz located 7'' from the base of the jet, coincident with the inner radio knot detected by Rodriguez et al. in 2009 but at lower surface brightness. We interpret this as due to expansion of post-shock ionized gas in the three years between observations.

  13. A DEEP VERY LARGE ARRAY RADIO CONTINUUM SURVEY OF THE CORE AND OUTSKIRTS OF THE COMA CLUSTER

    International Nuclear Information System (INIS)

    Miller, Neal A.; Hornschemeier, Ann E.; Mobasher, Bahram

    2009-01-01

    We present deep 1.4 GHz Very Large Array radio continuum observations of two ∼0.5 deg 2 fields in the Coma cluster of galaxies. The two fields, 'Coma 1' and 'Coma 3', correspond to the cluster core and southwest infall region and were selected on account of abundant preexisting multiwavelength data. In their most sensitive regions the radio data reach 22 μJy rms per 4.''4 beam, sufficient to detect (at 5σ) Coma member galaxies with L 1.4 G Hz = 1.3 x 10 20 W Hz -1 . The full catalog of radio detections is presented herein and consists of 1030 sources detected at ≥5σ, 628 of which are within the combined Coma 1 and Coma 3 area. We also provide optical identifications of the radio sources using data from the Sloan Digital Sky Survey. The depth of the radio observations allows us to detect active galactic nucleus in cluster elliptical galaxies with M r r r ∼ sun yr -1 .

  14. An Integrated Circuit for Radio Astronomy Correlators Supporting Large Arrays of Antennas

    Science.gov (United States)

    D'Addario, Larry R.; Wang, Douglas

    2016-01-01

    Radio telescopes that employ arrays of many antennas are in operation, and ever larger ones are being designed and proposed. Signals from the antennas are combined by cross-correlation. While the cost of most components of the telescope is proportional to the number of antennas N, the cost and power consumption of cross-correlationare proportional to N2 and dominate at sufficiently large N. Here we report the design of an integrated circuit (IC) that performs digital cross-correlations for arbitrarily many antennas in a power-efficient way. It uses an intrinsically low-power architecture in which the movement of data between devices is minimized. In a large system, each IC performs correlations for all pairs of antennas but for a portion of the telescope's bandwidth (the so-called "FX" structure). In our design, the correlations are performed in an array of 4096 complex multiply-accumulate (CMAC) units. This is sufficient to perform all correlations in parallel for 64 signals (N=32 antennas with 2 opposite-polarization signals per antenna). When N is larger, the input data are buffered in an on-chipmemory and the CMACs are re-used as many times as needed to compute all correlations. The design has been synthesized and simulated so as to obtain accurate estimates of the IC's size and power consumption. It isintended for fabrication in a 32 nm silicon-on-insulator process, where it will require less than 12mm2 of silicon area and achieve an energy efficiency of 1.76 to 3.3 pJ per CMAC operation, depending on the number of antennas. Operation has been analyzed in detail up to N = 4096. The system-level energy efficiency, including board-levelI/O, power supplies, and controls, is expected to be 5 to 7 pJ per CMAC operation. Existing correlators for the JVLA (N = 32) and ALMA (N = 64) telescopes achieve about 5000 pJ and 1000 pJ respectively usingapplication-specific ICs in older technologies. To our knowledge, the largest-N existing correlator is LEDA atN = 256; it

  15. Analysing radio-frequency coil arrays in high-field magnetic resonance imaging by the combined field integral equation method

    Energy Technology Data Exchange (ETDEWEB)

    Wang Shumin; Duyn, Jeff H [Laboratory of Functional and Molecular Imaging, National Institute of Neurological Disorders and Stroke, National Institutes of Health, 10 Center Drive, 10/B1D728, Bethesda, MD 20892 (United States)

    2006-06-21

    We present the combined field integral equation (CFIE) method for analysing radio-frequency coil arrays in high-field magnetic resonance imaging (MRI). Three-dimensional models of coils and the human body were used to take into account the electromagnetic coupling. In the method of moments formulation, we applied triangular patches and the Rao-Wilton-Glisson basis functions to model arbitrarily shaped geometries. We first examined a rectangular loop coil to verify the CFIE method and also demonstrate its efficiency and accuracy. We then studied several eight-channel receive-only head coil arrays for 7.0 T SENSE functional MRI. Numerical results show that the signal dropout and the average SNR are two major concerns in SENSE coil array design. A good design should be a balance of these two factors.

  16. Surveying the Dynamic Radio Sky with the Long Wavelength Demonstrator Array

    Science.gov (United States)

    2010-10-01

    radio wavelengths, there are well-known classes of transients, such as the Sun and ra- dio pulsars , as well as a long history of observ- ing transients...Rupen et al. 2002). Fur- ther, a series of observations and discoveries over the past decade have emphasized that the radio sky may be quite dynamic...Bailes 2010); intense giant pulses have been detected from the Crab pulsar (Hankins et al. 2003); and several as-yet unidentified radio transients have

  17. Multi-Beam Radio Frequency (RF) Aperture Arrays Using Multiplierless Approximate Fast Fourier Transform (FFT)

    Science.gov (United States)

    2017-08-01

    Fourier transform, discrete Fourier transform, digital array processing , antenna beamformers 16. SECURITY CLASSIFICATION OF: 17. LIMITATION OF...125 3.7 Simulation of 2-D Beams Cross Sections .................................................................... 125 3.7.1 8...unlimited. List of Figures Figure Page Figure 1: N-beam Array Processing System using a Linear Array

  18. Compact printed two dipole array antenna with a high front-back ratio for ultra-high-frequency radio-frequency identification handheld reader applications

    DEFF Research Database (Denmark)

    Liu, Qi; Zhang, Shuai; He, Sailing

    2015-01-01

    A printed two-dipole array antenna with a high front-back ratio is proposed for ultra-high-frequency (UHF) radio-frequency identification handheld readers. The proposed antenna is a parasitic dual-element array with the ends of both elements folded back towards each other for additional coupling....

  19. Astronomical Ecosystems

    Science.gov (United States)

    Neuenschwander, D. E.; Finkenbinder, L. R.

    2004-05-01

    Just as quetzals and jaguars require specific ecological habitats to survive, so too must planets occupy a tightly constrained astronomical habitat to support life as we know it. With this theme in mind we relate the transferable features of our elementary astronomy course, "The Astronomical Basis of Life on Earth." Over the last five years, in a team-taught course that features a spring break field trip to Costa Rica, we have introduced astronomy through "astronomical ecosystems," emphasizing astronomical constraints on the prospects for life on Earth. Life requires energy, chemical elements, and long timescales, and we emphasize how cosmological, astrophysical, and geological realities, through stabilities and catastrophes, create and eliminate niches for biological life. The linkage between astronomy and biology gets immediate and personal: for example, studies in solar energy production are followed by hikes in the forest to examine the light-gathering strategies of photosynthetic organisms; a lesson on tides is conducted while standing up to our necks in one on a Pacific beach. Further linkages between astronomy and the human timescale concerns of biological diversity, cultural diversity, and environmental sustainability are natural and direct. Our experience of teaching "astronomy as habitat" strongly influences our "Astronomy 101" course in Oklahoma as well. This "inverted astrobiology" seems to transform our student's outlook, from the universe being something "out there" into something "we're in!" We thank the SNU Science Alumni support group "The Catalysts," and the SNU Quetzal Education and Research Center, San Gerardo de Dota, Costa Rica, for their support.

  20. VEGAS: VErsatile GBT Astronomical Spectrometer

    Science.gov (United States)

    Bussa, Srikanth; VEGAS Development Team

    2012-01-01

    The National Science Foundation Advanced Technologies and Instrumentation (NSF-ATI) program is funding a new spectrometer backend for the Green Bank Telescope (GBT). This spectrometer is being built by the CICADA collaboration - collaboration between the National Radio Astronomy Observatory (NRAO) and the Center for Astronomy Signal Processing and Electronics Research (CASPER) at the University of California Berkeley.The backend is named as VErsatile GBT Astronomical Spectrometer (VEGAS) and will replace the capabilities of the existing spectrometers. This backend supports data processing from focal plane array systems. The spectrometer will be capable of processing up to 1.25 GHz bandwidth from 8 dual polarized beams or a bandwidth up to 10 GHz from a dual polarized beam.The spectrometer will be using 8-bit analog to digital converters (ADC), which gives a better dynamic range than existing GBT spectrometers. There will be 8 tunable digital sub-bands within the 1.25 GHz bandwidth, which will enhance the capability of simultaneous observation of multiple spectral transitions. The maximum spectral dump rate to disk will be about 0.5 msec. The vastly enhanced backend capabilities will support several science projects with the GBT. The projects include mapping temperature and density structure of molecular clouds; searches for organic molecules in the interstellar medium; determination of the fundamental constants of our evolving Universe; red-shifted spectral features from galaxies across cosmic time and survey for pulsars in the extreme gravitational environment of the Galactic Center.

  1. Compact field programmable gate array-based pulse-sequencer and radio-frequency generator for experiments with trapped atoms

    Energy Technology Data Exchange (ETDEWEB)

    Pruttivarasin, Thaned, E-mail: thaned.pruttivarasin@riken.jp [Quantum Metrology Laboratory, RIKEN, Wako-shi, Saitama 351-0198 (Japan); Katori, Hidetoshi [Quantum Metrology Laboratory, RIKEN, Wako-shi, Saitama 351-0198 (Japan); Innovative Space-Time Project, ERATO, JST, Bunkyo-ku, Tokyo 113-8656 (Japan); Department of Applied Physics, Graduate School of Engineering, The University of Tokyo, Bunkyo-ku, Tokyo 113-8656 (Japan)

    2015-11-15

    We present a compact field-programmable gate array (FPGA) based pulse sequencer and radio-frequency (RF) generator suitable for experiments with cold trapped ions and atoms. The unit is capable of outputting a pulse sequence with at least 32 transistor-transistor logic (TTL) channels with a timing resolution of 40 ns and contains a built-in 100 MHz frequency counter for counting electrical pulses from a photo-multiplier tube. There are 16 independent direct-digital-synthesizers RF sources with fast (rise-time of ∼60 ns) amplitude switching and sub-mHz frequency tuning from 0 to 800 MHz.

  2. Radio Observations of Gamma-ray Novae

    Science.gov (United States)

    Linford, Justin D.; Chomiuk, L.; Ribeiro, V.; project, E.-Nova

    2014-01-01

    Recent detection of gamma-ray emission from classical novae by the Large Area Telescope (LAT) on board the Fermi Gamma-ray Space Telescope surprised many in the astronomical community. We present results from radio observations, obtained using the Karl G. Jansky Very Large Array (VLA), of three gamma-ray novae: Mon2012, Sco2012, and Del2013. Radio observations allow for the calculation of ejecta masses, place limits on the distances, and provide information about the gamma-ray emission mechanism for these sources.

  3. Astronomical optics

    CERN Document Server

    Schroeder, Daniel J

    1988-01-01

    Written by a recognized expert in the field, this clearly presented, well-illustrated book provides both advanced level students and professionals with an authoritative, thorough presentation of the characteristics, including advantages and limitations, of telescopes and spectrographic instruments used by astronomers of today.Key Features* Written by a recognized expert in the field* Provides both advanced level students and professionals with an authoritative, thorough presentation of the characteristics, including advantages and limitations, of telescopes and spectrographic i

  4. Harvey Butcher: a passion for astronomical instrumentation

    Science.gov (United States)

    Bhathal, Ragbir

    2014-11-01

    This paper covers some aspects of the scientific life of Harvey Butcher who was the Director of the Research School for Astronomy and Astrophysics at the Australian National University in Canberra from September 2007 to January 2013. He has made significant contributions to research on the evolution of galaxies, nucleosynthesis, and on the design and implementation of advanced astronomical instrumentation including LOFAR (Low Frequency Array Radio telescope). He is well known for his discovery of the Butcher-Oemler effect. Before coming to Australia he was the Director of the Netherlands Foundation for Research in Astronomy from September 1991 to January 2007. In 2005 he was awarded a Knighthood in the Order of the Netherlands Lion for contributions to interdisciplinary science, innovation and public outreach.This paper is based on an interview conducted by the author with Harvey Butcher for the National Project on Significant Australian Astronomers sponsored by the National Library of Australia. Except otherwise stated, all quotations used in this paper are from the Butcher interview which has been deposited in the Oral History Archives of the National Library.

  5. Relativistic jets and the most powerful radio sources in the universe

    International Nuclear Information System (INIS)

    Bridle, A.

    1987-01-01

    Relativistic jets, which are beams of particles and magnetic fields emitting synchrotron radiation that emanate from black holes at the centers of galaxies and quasars, have been one of the most exciting discoveries made at the Very Large Array (VLA) operated by the National Radio Astronomy Observatory (NRAO). The VLA is an array of 27 antennas, each 25 meters in diameter, distributed in a Y-formation with two branches 21 kilometers long and one branch 19 kilometers long. Astronomers can use it to study relativistic jets that generate intense natural radio sources (or transmitters). These sources, associated with regions hundreds of thousands of light years across, are the most powerful in the universe in energy output. In his lecture, Bridle describes how consecutive advances in imaging techniques for radio astronomy have uncovered the properties of the powerful radio sources, culminating in the discovery at the VLA that many of these sources contain radio emitting jets. He then describes some of the NRAO's research on these jets, and discusses the jets' physical properties. He concludes with an outlook for the future: the NRAO's Very Long Baseline Array (VLBA) is to be completed in the early 1990's. The VLBA is an array of ten radio telescopes distributed from Hawaii to St. Croix, from the Canadian border to Texas. With the VLBA, astronomers plan to look more deeply into these radio sources. 15 figs

  6. An end-to-end computing model for the Square Kilometre Array

    NARCIS (Netherlands)

    Jongerius, R.; Wijnholds, S.; Nijboer, R.; Corporaal, H.

    2014-01-01

    For next-generation radio telescopes such as the Square Kilometre Array, seemingly minor changes in scientific constraints can easily push computing requirements into the exascale domain. The authors propose a model for engineers and astronomers to understand these relations and make tradeoffs in

  7. Astronomical chemistry.

    Science.gov (United States)

    Klemperer, William

    2011-01-01

    The discovery of polar polyatomic molecules in higher-density regions of the interstellar medium by means of their rotational emission detected by radioastronomy has changed our conception of the universe from essentially atomic to highly molecular. We discuss models for molecule formation, emphasizing the general lack of thermodynamic equilibrium. Detailed chemical kinetics is needed to understand molecule formation as well as destruction. Ion molecule reactions appear to be an important class for the generally low temperatures of the interstellar medium. The need for the intrinsically high-quality factor of rotational transitions to definitively pin down molecular emitters has been well established by radioastronomy. The observation of abundant molecular ions both positive and, as recently observed, negative provides benchmarks for chemical kinetic schemes. Of considerable importance in guiding our understanding of astronomical chemistry is the fact that the larger molecules (with more than five atoms) are all organic.

  8. Murchison Widefield Array Limits on Radio Emission from ANTARES Neutrino Events

    NARCIS (Netherlands)

    Croft, S.; van Haren, H.; MWA Collaboration; Antares Collaboration; TAROT Collaboration; ROTSE Collaboration

    2016-01-01

    We present a search, using the Murchison Widefield Array (MWA), for electromagnetic (EM) counterparts to twocandidate high-energy neutrino events detected by the ANTARES neutrino telescope in 2013 November and 2014March. These events were selected by ANTARES because they are consistent, within 0°.4,

  9. Radio frequency interference noise reduction using a field programmable gate array for SQUID applications

    International Nuclear Information System (INIS)

    Sakuta, K; Narita, Y; Itozaki, H

    2007-01-01

    It is important to remove large environmental noise in superconducting quantum interference device (SQUID) measurement without magnetic shielding. Active noise control (ANC) is one of the effective methods to reduce environmental noise. Recently, SQUIDs have been used in various applications at high frequencies, such as nuclear quadrupole resonance (NQR). The NQR frequency from explosives is in the range 0.5-5 MHz. In this case, an NQR sensor is exposed to AM radio frequency interference (RFI). The feasibility of the ANC system for RFI that used digital signal processing was studied. Our investigation showed that this digital ANC system can be applied to SQUID measurements for RFI suppression

  10. First detection of thermal radio emission from solar-type stars with the Karl G. Jansky very large array

    Energy Technology Data Exchange (ETDEWEB)

    Villadsen, Jackie; Hallinan, Gregg; Bourke, Stephen [Department of Astronomy, California Institute of Technology, 1200 E. California Ave., Pasadena, CA 91125 (United States); Güdel, Manuel [Department of Astrophysics, University of Vienna, Türkenschanzstrasse 17, A-1180 Vienna (Austria); Rupen, Michael, E-mail: jrv@astro.caltech.edu [National Radio Astronomy Observatory, Socorro, NM 87801 (United States)

    2014-06-20

    We present the first detections of thermal radio emission from the atmospheres of solar-type stars τ Cet, η Cas A, and 40 Eri A. These stars all resemble the Sun in age and level of magnetic activity, as indicated by X-ray luminosity and chromospheric emission in Ca II H and K lines. We observed these stars with the Karl G. Jansky Very Large Array with sensitivities of a few μJy at combinations of 10.0, 15.0, and 34.5 GHz. τ Cet, η Cas A, and 40 Eri A are all detected at 34.5 GHz with signal-to-noise ratios of 6.5, 5.2, and 4.5, respectively. 15.0 GHz upper limits imply a rising spectral index greater than 1.0 for τ Cet and 1.6 for η Cas A, at the 95% confidence level. The measured 34.5 GHz flux densities correspond to stellar disk-averaged brightness temperatures of roughly 10,000 K, similar to the solar brightness temperature at the same frequency. We explain this emission as optically thick thermal free-free emission from the chromosphere, with possible contributions from coronal gyroresonance emission above active regions and coronal free-free emission. These and similar quality data on other nearby solar-type stars, when combined with Atacama Large Millimeter/Submillimeter Array observations, will enable the construction of temperature profiles of their chromospheres and lower transition regions.

  11. First detection of thermal radio emission from solar-type stars with the Karl G. Jansky very large array

    International Nuclear Information System (INIS)

    Villadsen, Jackie; Hallinan, Gregg; Bourke, Stephen; Güdel, Manuel; Rupen, Michael

    2014-01-01

    We present the first detections of thermal radio emission from the atmospheres of solar-type stars τ Cet, η Cas A, and 40 Eri A. These stars all resemble the Sun in age and level of magnetic activity, as indicated by X-ray luminosity and chromospheric emission in Ca II H and K lines. We observed these stars with the Karl G. Jansky Very Large Array with sensitivities of a few μJy at combinations of 10.0, 15.0, and 34.5 GHz. τ Cet, η Cas A, and 40 Eri A are all detected at 34.5 GHz with signal-to-noise ratios of 6.5, 5.2, and 4.5, respectively. 15.0 GHz upper limits imply a rising spectral index greater than 1.0 for τ Cet and 1.6 for η Cas A, at the 95% confidence level. The measured 34.5 GHz flux densities correspond to stellar disk-averaged brightness temperatures of roughly 10,000 K, similar to the solar brightness temperature at the same frequency. We explain this emission as optically thick thermal free-free emission from the chromosphere, with possible contributions from coronal gyroresonance emission above active regions and coronal free-free emission. These and similar quality data on other nearby solar-type stars, when combined with Atacama Large Millimeter/Submillimeter Array observations, will enable the construction of temperature profiles of their chromospheres and lower transition regions.

  12. PROSPECTS FOR THE DETECTION OF FAST RADIO BURSTS WITH THE MURCHISON WIDEFIELD ARRAY

    International Nuclear Information System (INIS)

    Trott, Cathryn M.; Tingay, Steven J.; Wayth, Randall B.

    2013-01-01

    Fast radio bursts (FRBs) are short timescale ( 2 ) and wide field-of-view (FOV, ∼ 1000 deg 2 at ν = 200 MHz). We compute the expected number of FRB detections for the MWA assuming a source population consistent with the reported detections. Our formalism properly accounts for the frequency-dependence of the antenna primary beam, the MWA system temperature, and unknown spectral index of the source population, for three modes of FRB detection: coherent; incoherent; and fast imaging. We find that the MWA's sensitivity and large FOV combine to provide the expectation of multiple detectable events per week in all modes, potentially making it an excellent high time resolution science instrument. Deviations of the expected number of detections from actual results will provide a strong constraint on the assumptions made for the underlying source population and intervening plasma distribution

  13. Astronomers Discover Six-Image Gravitational Lens

    Science.gov (United States)

    2001-08-01

    An international team of astronomers has used the National Science Foundation's Very Long Baseline Array (VLBA) radio telescope and NASA's Hubble Space Telescope (HST) to discover the first gravitational lens in which the single image of a very distant galaxy has been split into six different images. The unique configuration is produced by the gravitational effect of three galaxies along the line of sight between the more-distant galaxy and Earth. Optical and Radio Images of Gravitational Lens "This is the first gravitational lens with more than four images of the background object that is produced by a small group of galaxies rather than a large cluster of galaxies," said David Rusin, who just received his Ph.D. from the University of Pennsylvania. "Such systems are expected to be extremely rare, so this discovery is an important stepping stone. Because this is an intermediate case between gravitational lenses produced by single galaxies and lenses produced by large clusters of galaxies, it will give us insights we can't get from other types of lenses," Rusin added. The gravitational lens, called CLASS B1359+154, consists of a galaxy more than 11 billion light-years away in the constellation Bootes, with a trio of galaxies more than 7 billion light-years away along the same line of sight. The more-distant galaxy shows signs that it contains a massive black hole at its core and also has regions in which new stars are forming. The gravitational effect of the intervening galaxies has caused the light and radio waves from the single, more-distant galaxy to be "bent" to form six images as seen from Earth. Four of these images appear outside the triangle formed by the three intermediate galaxies and two appear inside that triangle. "This lens system is a very interesting case to study because it is more complicated than lenses produced by single galaxies, and yet simpler than lenses produced by clusters of numerous galaxies," said Chris Kochanek of the Harvard

  14. Radio stars

    International Nuclear Information System (INIS)

    Hjellming, R.M.; Gibson, D.M.

    1985-01-01

    Studies of stellar radio emission became an important field of research in the 1970's and have now expanded to become a major area of radio astronomy with the advent of new instruments such as the Very Large Array in New Mexico and transcontinental telescope arrays. This volume contains papers from the workshop on stellar continuum radio astronomy held in Boulder, Colorado, and is the first book on the rapidly expanding field of radio emission from stars and stellar systems. Subjects covered include the observational and theoretical aspects of stellar winds from both hot and cool stars, radio flares from active double star systems and red dwarf stars, bipolar flows from star-forming regions, and the radio emission from X-ray binaries. (orig.)

  15. RADIO SOURCES FROM A 31 GHz SKY SURVEY WITH THE SUNYAEV-ZEL'DOVICH ARRAY

    International Nuclear Information System (INIS)

    Muchovej, Stephen; Hawkins, David; Lamb, James; Woody, David; Leitch, Erik; Carlstrom, John E.; Culverhouse, Thomas; Greer, Chris; Hennessy, Ryan; Loh, Michael; Marrone, Daniel P.; Pryke, Clem; Sharp, Matthew; Joy, Marshall; Miller, Amber; Mroczkowski, Tony

    2010-01-01

    We present the first sample of 31 GHz selected sources to flux levels of 1 mJy. From late 2005 to mid-2007, the Sunyaev-Zel'dovich Array observed 7.7 deg 2 of the sky at 31 GHz to a median rms of 0.18 mJy beam -1 . We identify 209 sources at greater than 5σ significance in the 31 GHz maps, ranging in flux from 0.7 mJy to ∼200 mJy. Archival NVSS data at 1.4 GHz and observations at 5 GHz with the Very Large Array are used to characterize the sources. We determine the maximum-likelihood integrated source count to be N(>S) = (27.2 ± 2.5)deg -2 x (S mJy ) -1.18±0.12 over the flux range 0.7-15 mJy. This result is significantly higher than predictions based on 1.4 GHz selected samples, a discrepancy which can be explained by a small shift in the spectral index distribution for faint 1.4 GHz sources. From comparison with previous measurements of sources within the central arcminute of massive clusters, we derive an overdensity of 6.8 ± 4.4, relative to field sources.

  16. Astronomers Unveiling Life's Cosmic Origins

    Science.gov (United States)

    2009-02-01

    the study of interstellar chemistry," Remijan said. Astronomers have already identified more than 150 molecules in interstellar space in the past 40 years, including complex organic compounds such as sugars and alcohols. "This is a major change in how we search for molecules in space," Remijan explained. "Before, people decided beforehand which molecules they were looking for, then searched in a very narrow band of radio frequencies emitted by those molecules. In this GBT survey, we've observed a wide range of frequencies, collected the data and immediately made it publicly available. Scientists anywhere can 'mine' this resource to find new molecules," he said. Another key development, presented by Crystal Brogan of the NRAO, showed that highly-detailed images of "protoclusters" of massive young stars reveal a complex mix of stars in different stages of formation, complicated gas motions, and numerous chemical clues to the physical conditions in such stellar nurseries. "We saw a much more complex picture than we had expected and now have new questions to answer," she said. Using the Smithsonian Astrophysical Observatory's Submillimeter Array (SMA) in Hawaii, Brogan and her colleagues studied a nebula 5,500 light-years from Earth in the constellation Scorpius where stars significantly more massive than our Sun are forming. "It's essential to understand what's going on in systems like this because most stars, Sun-like stars included, form in clusters," Brogan said. "The most massive stars in the cluster have a tremendous impact on the formation and environment of the rest of the cluster, including the less-massive stars and their planets," Brogan said, adding that "if we want to understand how solar systems that could support life form and evolve, we need to know how these giant stars affect their environment." Also, Brogan said, the massive young stars are surrounded by "hot cores" that include copious organic material that later may be spewed into interstellar space

  17. Radio sounding of the magnetosphere from a lunar-based VLF array

    Science.gov (United States)

    Green, James L.; Fung, Shing F.

    1994-01-01

    Using a lunar-based active radio transmitter and receiver system operating in the 'free space' wave modes, we can obtain much information on the structures and dynamics of remote magnetospheric plasma regions in a way similar to ionosondes. Powerful, narrow-band electromagnetic pulses can be transmitted over a wide frequency range (from 10 kHz to 1 MHz). The signals would be refracted and reflected off magnetospheric structures such as the plasmapause, plasmasheet, magnetopause, and the high and low latitude boundary layers. With a series of long dipole antennas, ranging in size from 400 m to 20 km with an output voltage ranging from 6 kV to less than 0.2 kV, a target plasma region at up to 100 R(sub E) can be explored. We illustrate this remote sensing technique by using the plasmasphere as a remote target, and modeling the propagations of the sounder transmitted and received pulses by ray tracing calculations.

  18. Comparison of Antenna Array Systems Using OFDM for Software Radio via the SIBIC Model

    Directory of Open Access Journals (Sweden)

    Robert D. Palmer

    2005-09-01

    Full Text Available This paper investigates the performance of two candidates for software radio WLAN, reconfigurable OFDM modulation and antenna diversity, in an indoor environment. The scenario considered is a 20 m×10 m×3 m room with two base units and one mobile unit. The two base units use omnidirectional antennas to transmit and the mobile unit uses either a single antenna with equalizer, a fixed beamformer with equalizer, or an adaptive beamformer with equalizer to receive. The modulation constellation of the data is QPSK and 16-QAM. The response of the channel at the mobile unit is simulated using a three-dimensional indoor WLAN propagation model that generates multipath components with realistic spatial and temporal correlation. An underlying assumption of the scenario is that existing antenna hardware is available and could be exploited if software processing resources are allocated. The results of the simulations indicate that schemes using more resources outperform simpler schemes in most cases. This implies that desired user performance could be used to dynamically assign software processing resources to the demands of a particular indoor WLAN channel if such resources are available.

  19. The Hartebeeshoek Radio Astronomy Observatory

    International Nuclear Information System (INIS)

    Nicolson, G.D.

    1986-01-01

    This article briefly discusses the questions, problems and study fields of the modern astronomer. Radioastronomy has made important contributions to the study of the evolution of stars and has given much information on the birth of stars while at the other extreme, studies of neutron stars and the radio emission from the remnants of supernova explosions have given further insight into the death of individual stars. Radio astronomical studies have learned astronomers much about the structure of the Milky way and some twenty years ago, in a search for new radio galaxies, quasars were discovered. Radioastronomy research in South Africa is carried out at the Hartebeesthoek Radio Astronomy Observatory

  20. Citizen Science Opportunity With the NASA Heliophysics Education Consortium (HEC)-Radio JOVE Project

    Science.gov (United States)

    Fung, S. F.; Higgins, C.; Thieman, J.; Garcia, L. N.; Young, C. A.

    2016-12-01

    The Radio JOVE project has long been a hands-on inquiry-based educational project that allows students, teachers and the general public to learn and practice radio astronomy by building their own radio antenna and receiver system from an inexpensive kit that operates at 20.1 MHz and/or using remote radio telescopes through the Internet. Radio JOVE participants observe and analyze natural radio emissions from Jupiter and the Sun. Within the last few years, several Radio JOVE amateurs have upgraded their equipment to make semi-professional spectrographic observations in the frequency band of 15-30 MHz. Due to the widely distributed Radio JOVE observing stations across the US, the Radio JOVE observations can uniquely augment observations by professional telescopes, such as the Long Wavelength Array (LWA) . The Radio JOVE project has recently partnered with the NASA Heliophysics Education Consortium (HEC) to work with students and interested amateur radio astronomers to establish additional spectrograph and single-frequency Radio JOVE stations. These additional Radio JOVE stations will help build a larger amateur radio science network and increase the spatial coverage of long-wavelength radio observations across the US. Our presentation will describe the Radio JOVE project within the context of the HEC. We will discuss the potential for citizen scientists to make and use Radio JOVE observations to study solar radio bursts (particularly during the upcoming solar eclipse in August 2017) and Jovian radio emissions. Radio JOVE observations will also be used to study ionospheric radio scintillation, promoting appreciation and understanding of this important space weather effect.

  1. Hydrogen Epoch of Reinozation Array (HERA) Calibrated FFT Correlator Simulation

    Science.gov (United States)

    Salazar, Jeffrey David; Parsons, Aaron

    2018-01-01

    The Hydrogen Epoch of Reionization Array (HERA) project is an astronomical radio interferometer array with a redundant baseline configuration. Interferometer arrays are being used widely in radio astronomy because they have a variety of advantages over single antenna systems. For example, they produce images (visibilities) closely matching that of a large antenna (such as the Arecibo observatory), while both the hardware and maintenance costs are significantly lower. However, this method has some complications; one being the computational cost of correlating data from all of the antennas. A correlator is an electronic device that cross-correlates the data between the individual antennas; these are what radio astronomers call visibilities. HERA, being in its early stages, utilizes a traditional correlator system. The correlator cost scales as N2, where N is the number of antennas in the array. The purpose of a redundant baseline configuration array setup is for the use of a more efficient Fast Fourier Transform (FFT) correlator. FFT correlators scale as Nlog2N. The data acquired from this sort of setup, however, inherits geometric delay and uncalibrated antenna gains. This particular project simulates the process of calibrating signals from astronomical sources. Each signal “received” by an antenna in the simulation is given random antenna gain and geometric delay. The “linsolve” Python module was used to solve for the unknown variables in the simulation (complex gains and delays), which then gave a value for the true visibilities. This first version of the simulation only mimics a one dimensional redundant telescope array detecting a small amount of sources located in the volume above the antenna plane. Future versions, using GPUs, will handle a two dimensional redundant array of telescopes detecting a large amount of sources in the volume above the array.

  2. OLFAR: the orbiting low frequency array, how a cube sat swarm becomes a novel radio astronomy instrument in space

    NARCIS (Netherlands)

    Bentum, Marinus Jan; Meijerink, Arjan; Boonstra, Albert Jan; Verhoeven, Chris; van der Veen, Alle-Jan

    2010-01-01

    To study the physical processes in the Universe, observations are done at various wavelengths, from Gamma rays to optical and radio frequencies. At this moment research at low frequencies is one of the major topics in radio astronomy. Several Earth-based radio telescopes are being built and will be

  3. Old Star's "Rebirth" Gives Astronomers Surprises

    Science.gov (United States)

    2005-04-01

    Astronomers using the National Science Foundation's Very Large Array (VLA) radio telescope are taking advantage of a once-in-a-lifetime opportunity to watch an old star suddenly stir back into new activity after coming to the end of its normal life. Their surprising results have forced them to change their ideas of how such an old, white dwarf star can re-ignite its nuclear furnace for one final blast of energy. Sakurai's Object Radio/Optical Images of Sakurai's Object: Color image shows nebula ejected thousands of years ago. Contours indicate radio emission. Inset is Hubble Space Telescope image, with contours indicating radio emission; this inset shows just the central part of the region. CREDIT: Hajduk et al., NRAO/AUI/NSF, ESO, StSci, NASA Computer simulations had predicted a series of events that would follow such a re-ignition of fusion reactions, but the star didn't follow the script -- events moved 100 times more quickly than the simulations predicted. "We've now produced a new theoretical model of how this process works, and the VLA observations have provided the first evidence supporting our new model," said Albert Zijlstra, of the University of Manchester in the United Kingdom. Zijlstra and his colleagues presented their findings in the April 8 issue of the journal Science. The astronomers studied a star known as V4334 Sgr, in the constellation Sagittarius. It is better known as "Sakurai's Object," after Japanese amateur astronomer Yukio Sakurai, who discovered it on February 20, 1996, when it suddenly burst into new brightness. At first, astronomers thought the outburst was a common nova explosion, but further study showed that Sakurai's Object was anything but common. The star is an old white dwarf that had run out of hydrogen fuel for nuclear fusion reactions in its core. Astronomers believe that some such stars can undergo a final burst of fusion in a shell of helium that surrounds a core of heavier nuclei such as carbon and oxygen. However, the

  4. Olfar: orbiting low frequency antenna for radio astronomy

    NARCIS (Netherlands)

    Bentum, Marinus Jan; Boonstra, Albert Jan

    2009-01-01

    New interesting astronomical science drivers for very low frequency radio astronomy have emerged, ranging from studies of the astronomical dark ages, the epoch of reionization, exoplanets, to ultra-high energy cosmic rays. However, astronomical observations with Earth-bound radio telescopes at very

  5. Astronomers gossip about the (cosmic) neighborhood.

    Science.gov (United States)

    Jayawardhana, R

    1994-09-09

    The Hague, Netherlands, last month welcomed 2000 astronomers from around the world for the 22nd General Assembly of the International Astronomical Union (IAU). From 15 to 27 August, they participated in symposia and discussions on topics ranging from the down-to-Earth issue of light and radio-frequency pollution to the creation of elements at the farthest reaches of time and space, in the big bang. Some of the most striking news, however, came in new findings from our galaxy and its immediate surroundings.

  6. Utrecht and Galactic Radio Astronomy

    NARCIS (Netherlands)

    van Woerden, H.

    Important roles in early Dutch Galactic radio astronomy were played by several Utrecht astronomers: Van de Hulst, Minnaert and Houtgast. The poster announcing the conference contained a number of pictures referring to scientific achievements of the Astronomical Institute Utrecht. One of these

  7. Orbiting Water Molecules Dance to Tune Of Galaxy's "Central Engine," Astronomers Say

    Science.gov (United States)

    2000-01-01

    A disk of water molecules orbiting a supermassive black hole at the core of a galaxy 60 million light-years away is "reverberating" in response to variations in the energy output from the galaxy's powerful "central engine" close to the black hole, astronomers say. The team of astronomers used the National Science Foundation's (NSF) Very Large Array (VLA) radio telescope in New Mexico and the 100-meter-diameter radio telescope of the Max Planck Institute for Radio Astronomy at Effelsberg, Germany, to observe the galaxy NGC 1068 in the constellation Cetus. They announced their findings today at the American Astronomical Society's meeting in Atlanta. The water molecules, in a disk some 5 light-years in diameter, are acting as a set of giant cosmic radio-wave amplifiers, called masers. Using energy radiated by the galaxy's "central engine," the molecules strengthen, or brighten, radio emission at a particular frequency as seen from Earth. "We have seen variations in the radio 'brightness' of these cosmic amplifiers that we believe were caused by variations in the energy output of the central engine," said Jack Gallimore, an astronomer at the National Radio Astronomy Observatory (NRAO) in Charlottesville, VA. "This could provide us with a valuable new tool for learning about the central engine itself," he added. Gallimore worked with Stefi Baum of the Space Telescope Science Institute in Baltimore, MD; Christian Henkel of the Max Planck Institute for Radio Astronomy in Bonn, Germany; Ian Glass of the South African Astronomical Observatory; Mark Claussen of the NRAO in Socorro, NM; and Almudena Prieto of the European Southern Observatory in Munich, Germany. "Our observations show that NGC 1068 is the second-known case of a giant disk of water molecules orbiting a supermassive black hole at a galaxy's core," Gallimore said. The first case was the galaxy NGC 4258 (Messier 106), whose disk of radio-amplifying water molecules was measured by the NSF's Very Long Baseline

  8. The effect of applied electric field on pulsed radio frequency and pulsed direct current plasma jet array

    International Nuclear Information System (INIS)

    Hu, J. T.; Liu, X. Y.; Liu, J. H.; Xiong, Z. L.; Liu, D. W.; Lu, X. P.; Iza, F.; Kong, M. G.

    2012-01-01

    Here we compare the plasma plume propagation characteristics of a 3-channel pulsed RF plasma jet array and those of the same device operated by a pulsed dc source. For the pulsed-RF jet array, numerous long life time ions and metastables accumulated in the plasma channel make the plasma plume respond quickly to applied electric field. Its structure similar as “plasma bullet” is an anode glow indeed. For the pulsed dc plasma jet array, the strong electric field in the vicinity of the tube is the reason for the growing plasma bullet in the launching period. The repulsive forces between the growing plasma bullets result in the divergence of the pulsed dc plasma jet array. Finally, the comparison of 309 nm and 777 nm emissions between these two jet arrays suggests the high chemical activity of pulsed RF plasma jet array.

  9. Astronomical Surveys and Big Data

    Directory of Open Access Journals (Sweden)

    Mickaelian Areg M.

    2016-03-01

    Full Text Available Recent all-sky and large-area astronomical surveys and their catalogued data over the whole range of electromagnetic spectrum, from γ-rays to radio waves, are reviewed, including such as Fermi-GLAST and INTEGRAL in γ-ray, ROSAT, XMM and Chandra in X-ray, GALEX in UV, SDSS and several POSS I and POSS II-based catalogues (APM, MAPS, USNO, GSC in the optical range, 2MASS in NIR, WISE and AKARI IRC in MIR, IRAS and AKARI FIS in FIR, NVSS and FIRST in radio range, and many others, as well as the most important surveys giving optical images (DSS I and II, SDSS, etc., proper motions (Tycho, USNO, Gaia, variability (GCVS, NSVS, ASAS, Catalina, Pan-STARRS, and spectroscopic data (FBS, SBS, Case, HQS, HES, SDSS, CALIFA, GAMA. An overall understanding of the coverage along the whole wavelength range and comparisons between various surveys are given: galaxy redshift surveys, QSO/AGN, radio, Galactic structure, and Dark Energy surveys. Astronomy has entered the Big Data era, with Astrophysical Virtual Observatories and Computational Astrophysics playing an important role in using and analyzing big data for new discoveries.

  10. The Practical Astronomer

    Science.gov (United States)

    Koester, Jack

    "The Practical Astronomer" by Thomas Dick, LLD, E.C. & J. Biddle, Philadelphia, 1849, is reviewed. Information on telescope makers and astronomers can be found. Mentioned are: Fraunhofer; John Herschel; Lawson; Dollond; Tulley; W. & S. Jones; and S.W. Burnham.

  11. NRAO Astronomer Wins Prestigious Guggenheim Fellowship

    Science.gov (United States)

    2010-04-01

    Dr. Dale Frail, an astronomer at the National Radio Astronomy Observatory (NRAO) in Socorro, New Mexico, has been awarded a prestigious Guggenheim Fellowship, according to the John Simon Guggenheim Memorial Foundation. The Guggenheim Foundation describes its fellowships as "mid-career" awards "intended for men and women who have already demonstrated exceptional capacity for productive scholarship or exceptional creative ability in the arts." Frail, 48, has worked at the NRAO for more than 20 years, first as a postdoctoral fellow, and then as a staff scientist. He received his bachelor's degree in physics from Acadia University in Nova Scotia, and his Ph.D in astronomy from the University of Toronto. Frail is best known for his landmark contributions to the understanding of gamma ray bursts, making critical measurements that provided key insights into the mechanisms of these superenergetic and once-mysterious explosions. He also has made important contributions to the understanding of other astronomical phenomena, including pulsars and their neighborhoods, supernova remnants, and magnetars. In 1992, he was the co-discoverer, with Alex Wolszczan, of the first planets outside our own solar system. "We congratulate Dale on this well-deserved honor that recognizes not only his past achievements but also his potential for exciting scientific work in the future," said Dr. Fred K.Y. Lo, NRAO Director. "We're very proud to see one of our scientists receive such a great honor," Lo added. Frail is one of 180 recipients of this year's Guggenheim Fellowships, chosen from some 3,000 applicants. The fellowships were established in 1925 and past recipients include photographer Ansel Adams, author Saul Bellow, former Secretary of State Henry Kissinger, and chemist Linus Pauling. 102 Guggenheim Fellows have subsequently won Nobel Prizes, and others have received Pulitzer Prizes and other honors. As a Guggenheim Fellow, Frail intends to intensify his research in the areas of pulsars

  12. Launch Will Create a Radio Telescope Larger than Earth

    Science.gov (United States)

    Baseline Interferometry project at JPL. "Observations of cosmic masers -- naturally-occurring microwave radio amplifiers -- will tell us new things about the process of star formation and activity in the heart of other galaxies." "By the 1980s, radio astronomers were observing the universe with assemblages of radio telescopes whose resolving power was limited only by the size of the Earth. Now, through a magnificent international effort, we will be able to break this barrier and see fine details of celestial objects that are beyond the reach of a purely ground-based telescope array. We anticipate a rich harvest of new scientific knowledge from VSOP," said Dr. Paul Vanden Bout, Director of NRAO. In the first weeks after launch, scientists and engineers will "test the deployment of the reflecting mesh telescope in orbit, the wide-band data link from the satellite to the ground, the performance of the low noise amplifiers in orbit, and the high-precision orbit determination and attitude control necessary for VLBI observations with an orbiting telescope," according to Dr. Joel Smith, manager of the U.S. Space VLBI project at JPL. Scientific observations are expected to begin in May. The 26-foot diameter orbiting radio telescope will observe celestial radio sources in concert with a number of the world's ground-based radio telescopes. The 1,830-pound satellite will be launched from ISAS' Kagoshima Space Center, at the southern tip of Kyushu, one of Japan's main islands, and will be the first launch with ISAS' new M-5 series rocket. The satellite will go into an elliptical orbit, varying between 620 to 12,400 miles above the Earth's surface. This orbit provides a wide range of distances between the satellite and ground-based telescopes, which is important for producing a high-quality image of the radio source being observed. One orbit of the Earth will take about six hours. The satellite's observations will concentrate on some of the most distant and intriguing objects in the

  13. Active galactic nuclei cores in infrared-faint radio sources. Very long baseline interferometry observations using the Very Long Baseline Array

    Science.gov (United States)

    Herzog, A.; Middelberg, E.; Norris, R. P.; Spitler, L. R.; Deller, A. T.; Collier, J. D.; Parker, Q. A.

    2015-06-01

    Context. Infrared-faint radio sources (IFRS) form a new class of galaxies characterised by radio flux densities between tenths and tens of mJy and faint or absent infrared counterparts. It has been suggested that these objects are radio-loud active galactic nuclei (AGNs) at significant redshifts (z ≳ 2). Aims: Whereas the high redshifts of IFRS have been recently confirmed based on spectroscopic data, the evidence for the presence of AGNs in IFRS is mainly indirect. So far, only two AGNs have been unquestionably confirmed in IFRS based on very long baseline interferometry (VLBI) observations. In this work, we test the hypothesis that IFRS contain AGNs in a large sample of sources using VLBI. Methods: We observed 57 IFRS with the Very Long Baseline Array (VLBA) down to a detection sensitivity in the sub-mJy regime and detected compact cores in 35 sources. Results: Our VLBA detections increase the number of VLBI-detected IFRS from 2 to 37 and provide strong evidence that most - if not all - IFRS contain AGNs. We find that IFRS have a marginally higher VLBI detection fraction than randomly selected sources with mJy flux densities at arcsec-scales. Moreover, our data provide a positive correlation between compactness - defined as the ratio of milliarcsec- to arcsec-scale flux density - and redshift for IFRS, but suggest a decreasing mean compactness with increasing arcsec-scale radio flux density. Based on these findings, we suggest that IFRS tend to contain young AGNs whose jets have not formed yet or have not expanded, equivalent to very compact objects. We found two IFRS that are resolved into two components. The two components are spatially separated by a few hundred milliarcseconds in both cases. They might be components of one AGN, a binary black hole, or the result of gravitational lensing.

  14. The radio-X-ray relation as a star formation indicator: results from the Very Large Array-Extended Chandra Deep Field-South

    Science.gov (United States)

    Vattakunnel, S.; Tozzi, P.; Matteucci, F.; Padovani, P.; Miller, N.; Bonzini, M.; Mainieri, V.; Paolillo, M.; Vincoletto, L.; Brandt, W. N.; Luo, B.; Kellermann, K. I.; Xue, Y. Q.

    2012-03-01

    In order to trace the instantaneous star formation rate (SFR) at high redshift, and thus help in understanding the relation between the different emission mechanisms related to star formation, we combine the recent 4-Ms Chandra X-ray data and the deep Very Large Array radio data in the Extended Chandra Deep Field-South region. We find 268 sources detected both in the X-ray and radio bands. The availability of redshifts for ˜95 per cent of the sources in our sample allows us to derive reliable luminosity estimates and the intrinsic properties from X-ray analysis for the majority of the objects. With the aim of selecting sources powered by star formation in both bands, we adopt classification criteria based on X-ray and radio data, exploiting the X-ray spectral features and time variability, taking advantage of observations scattered across more than 10 years. We identify 43 objects consistent with being powered by star formation. We also add another 111 and 70 star-forming candidates detected only in the radio and X-ray bands, respectively. We find a clear linear correlation between radio and X-ray luminosity in star-forming galaxies over three orders of magnitude and up to z˜ 1.5. We also measure a significant scatter of the order of 0.4 dex, higher than that observed at low redshift, implying an intrinsic scatter component. The correlation is consistent with that measured locally, and no evolution with redshift is observed. Using a locally calibrated relation between the SFR and the radio luminosity, we investigate the LX(2-10 keV)-SFR relation at high redshift. The comparison of the SFR measured in our sample with some theoretical models for the Milky Way and M31, two typical spiral galaxies, indicates that, with current data, we can trace typical spirals only at z≤ 0.2, and strong starburst galaxies with SFRs as high as ˜100 M⊙ yr-1, up to z˜ 1.5.

  15. LOFAR, the low frequency array

    Science.gov (United States)

    Vermeulen, R. C.

    2012-09-01

    LOFAR, the Low Frequency Array, is a next-generation radio telescope designed by ASTRON, with antenna stations concentrated in the north of the Netherlands and currently spread into Germany, France, Sweden and the United Kingdom; plans for more LOFAR stations exist in several other countries. Utilizing a novel, phased-array design, LOFAR is optimized for the largely unexplored low frequency range between 30 and 240 MHz. Digital beam-forming techniques make the LOFAR system agile and allow for rapid re-pointing of the telescopes as well as the potential for multiple simultaneous observations. Processing (e.g. cross-correlation) takes place in the LOFAR BlueGene/P supercomputer, and associated post-processing facilities. With its dense core (inner few km) array and long (more than 1000 km) interferometric baselines, LOFAR reaches unparalleled sensitivity and resolution in the low frequency radio regime. The International LOFAR Telescope (ILT) is now issuing its first call for observing projects that will be peer reviewed and selected for observing starting in December. Part of the allocations will be made on the basis of a fully Open Skies policy; there are also reserved fractions assigned by national consortia in return for contributions from their country to the ILT. In this invited talk, the gradually expanding complement of operationally verified observing modes and capabilities are reviewed, and some of the exciting first astronomical results are presented.

  16. Astronomers Get Closest Look Yet At Milky Way's Mysterious Core

    Science.gov (United States)

    2005-11-01

    Astronomers have gotten their deepest glimpse into the heart of our Milky Way Galaxy, peering closer to the supermassive black hole at the Galaxy's core then ever before. Using the National Science Foundation's continent-wide Very Long Baseline Array (VLBA), they found that a radio-wave-emitting object at the Galaxy's center would nearly fit between the Earth and the Sun. This is half the size measured in any previous observation. "We're getting tantalizingly close to being able to see an unmistakable signature that would provide the first concrete proof of a supermassive black hole at a galaxy's center," said Zhi-Qiang Shen, of the Shanghai Astronomical Observatory and the Chinese Academy of Sciences. A black hole is a concentration of mass so dense that not even light can escape its powerful gravitational pull. Milky Way Nucleus The Milky Way's nucleus, as seen with the VLA. Sagittarius A* is the bright white dot at center. CREDIT: NRAO/AUI/NSF, Jun-Hui Zhao, W.M. Goss (Click on Image for Larger Version) The astronomers used the VLBA to measure the size of an object called Sagittarius A* (pronounced "A-star") that marks the exact center of our Galaxy. Last year, a different team announced that their measurements showed the object would fit inside the complete circle of Earth's orbit around the Sun. Shen and his team, by observing at a higher radio frequency, measured Sagittarius A* as half that size. A mass equal to four million Suns is known to lie within Sagittarius A*, and the new measurement makes the case for a black hole even more compelling than it was previously. Scientists simply don't know of any long-lasting object other than a black hole that could contain this much mass in such a small area. However, they would like to see even stronger proof of a black hole. "The extremely strong gravitational pull of a black hole has several effects that would produce a distinctive 'shadow' that we think we could see if we can image details about half as small as

  17. UKRVO Astronomical WEB Services

    Directory of Open Access Journals (Sweden)

    Mazhaev, O.E.

    2017-01-01

    Full Text Available Ukraine Virtual Observatory (UkrVO has been a member of the International Virtual Observatory Alliance (IVOA since 2011. The virtual observatory (VO is not a magic solution to all problems of data storing and processing, but it provides certain standards for building infrastructure of astronomical data center. The astronomical databases help data mining and offer to users an easy access to observation metadata, images within celestial sphere and results of image processing. The astronomical web services (AWS of UkrVO give to users handy tools for data selection from large astronomical catalogues for a relatively small region of interest in the sky. Examples of the AWS usage are showed.

  18. An astronomical murder?

    Science.gov (United States)

    Belenkiy, Ari

    2010-04-01

    Ari Belenkiy examines the murder of Hypatia of Alexandria, wondering whether problems with astronomical observations and the date of Easter led to her becoming a casualty of fifth-century political intrigue.

  19. The amateur astronomer

    CERN Document Server

    Moore, Patrick

    2006-01-01

    Introduces astronomy and amateur observing together. This edition includes photographs and illustrations. The comprehensive appendices provide hints and tips, as well as data for every aspect of amateur astronomy. This work is useful for amateur astronomers

  20. The measurement of fringing fields in a radio-frequency hyperthermia array with emphasis on bolus size

    NARCIS (Netherlands)

    Wiersma, J.; van Dijk, J. D.; Sijbrands, J.; Schneider, C. J.

    1998-01-01

    The limited aperture size through which the em-field of the applicator is emanated and the constraining of this em-field near the bolus' edge is related to the appearance of superficial 'hot spot' phenomena in radiative hyperthermia. Regarding systems based on the concept of the annular phased array

  1. The anatomy of a radio source hot spot : Very large baseline array imaging of 3C 205

    NARCIS (Netherlands)

    Lonsdale, CJ; Barthel, PD

    Total intensity and linear polarization Very Long Baseline Array (VLBA) images of the high-redshift quasar 3C 205 at a wavelength of 18 cm reveal a complex curved hot-spot structure with polarization percentages frequently as high as 70%. A one-sided jet is detected emerging from the central

  2. Astronomers' Do-It-Yourself Project Opening A New Window on the Universe

    Science.gov (United States)

    1999-05-01

    Rolling up their sleeves to build and install new equipment for the National Science Foundation's (NSF) Very Large Array (VLA) radio telescope, a team of astronomers has opened a new window on the universe, revealing tantalizing new information about the explosions of massive stars, the workings of galaxies with supermassive black holes at their centers, and clusters of galaxies. "We're going back to the region of wavelengths where Karl Jansky started radio astronomy in 1932," said Namir Kassim, of the Naval Research Laboratory (NRL), in Washington, D.C. "This is one of the most poorly explored regions of the electromagnetic spectrum, yet it offers tremendous potential to learn exciting new information about everything from the Sun and planets to galaxy clusters and the universe itself," Kassim said. Kassim, along with Rick Perley of the National Radio Astronomy Observatory (NRAO) in Socorro, NM; William Erickson, a professor emeritus at the University of Maryland; and Joseph Lazio, also of NRL, presented results of their observations with the new VLA system at the American Astronomical Society's meeting in Chicago. The new system uses the 27 dish antennas of the VLA, each 25 meters (82 feet) in diameter, to receive cosmic radio emissions at a frequency of 74 MHz, or a wavelength of about four meters. This frequency, lower than that of the FM broadcast band, is far below the usual frequencies, 1- 50 GHz, used for radio astronomy. "Though the region of 15-150 MHz is where Jansky and Grote Reber did the first radio-astronomy work in the 1930s and 1940s, it has long been neglected because of technical difficulties of working in that region," said Perley. Still, the astronomers said, there is much to be learned by studying the universe at these wavelengths. "There are phenomena associated with the Sun and planets, with other objects in our own Milky Way Galaxy, and with other galaxies and clusters of galaxies, and potentially ancient emission from the Universe itself

  3. Search for PeVatrons at the Galactic Center using a radio air-shower array at the South Pole

    Energy Technology Data Exchange (ETDEWEB)

    Balagopal V, A.; Schroeder, F.G. [Karlsruher Institut fuer Technologie (KIT), Institut fuer Experimentelle Teilchenphysik, Karlsruhe (Germany); Haungs, A.; Huege, T. [Karlsruher Institut fuer Technologie (KIT), Institut fuer Kernphysik, Karlsruhe (Germany)

    2018-02-15

    The South Pole, which hosts the IceCube Neutrino Observatory, has a complete and around-the-clock exposure to the Galactic Center. Hence, it is an ideal location to search for gamma rays of PeV energy coming from the Galactic Center. However, it is hard to detect air showers initiated by these gamma rays using cosmic-ray particle detectors due to the low elevation of the Galactic Center. The use of antennas to measure the radio footprint of these air showers will help in this case, and would allow for a 24/7 operation time. So far, only air showers with energies well above 10{sup 16} eV have been detected with the radio technique. Thus, the energy threshold has to be lowered for the detection of gamma-ray showers of PeV energy. This can be achieved by optimizing the frequency band in order to obtain a higher level of signal-to-noise ratio. With such an approach, PeV gamma-ray showers with high inclination can be measured at the South Pole. (orig.)

  4. Low-frequency synthesis array in earth orbit

    International Nuclear Information System (INIS)

    Jones, D.L.; Preston, R.A.; Kuiper, T.B.H.

    1987-01-01

    The scientific objectives and design concept of a space-based VLBI array for high-resolution astronomical observations at 1-30 MHz are discussed. The types of investigations calling for such an array include radio spectroscopy of individual objects, measurement of the effects of scattering and refraction by the interplanetary medium (IPM) and the ISM, mapping the distribution of low-energy cosmic-ray electrons, and determining the extent of the Galactic halo. Consideration is given to the limitations imposed on an LF VLBI array by the ionosphere, the IPM, and the ISM; the calibration advantages offered by circular polar orbits of slightly differing ascending-node longitude for the array satellites; and collection of the IF data streams from the array satellites by one master satellite prior to transmission to the ground. It is shown that determination of the three-dimensional array geometry by means of intersatellite radio links is feasible if there are at least seven spacecraft in the array

  5. NRAO Astronomer Wins Max-Planck Research Award

    Science.gov (United States)

    2005-04-01

    Dr. Christopher Carilli, a National Radio Astronomy Observatory (NRAO) astronomer in Socorro, New Mexico, has been chosen to receive the prestigious Max Planck Research Award from the Alexander von Humboldt Foundation and the Max Planck Society in Germany. Christopher Carilli Dr. Christopher Carilli Click on image for more photos CREDIT: NRAO/AUI/NSF Carilli, a radio astronomer, and German particle physicist Christof Wetterich are the 2005 recipients of the award, conferred on "one researcher working in Germany and one working abroad who have already gained an international reputation and who are expected to produce outstanding achievements in the framework of international collaboration," according to an announcement from the Humboldt Foundation. "This is a great honor for Chris, and we are proud to see him receive such important international recognition for the excellence of his research," said NRAO Director Fred K.Y. Lo. Carilli's research has focused on studying very distant galaxies in the early Universe, and a quest to find the first luminous objects, such as stars or galaxies, to emerge. His most recent interests focus on unveiling the mysteries of what cosmologists call the "Epoch of Reionization," when the first stars and galaxies ionized the neutral hydrogen that pervaded the young Universe. Carilli and his research colleagues have used NRAO's Very Large Array and other radio telescopes to discover that the molecular raw material for star formation already was present in a galaxy seen as it was about 800 million years after the Big Bang, less than 1/16 the current age of the Universe. The Max Planck Research Award provides 750,000 Euros (currently about $900,000), to be used over five years, for research. The funding is provided by the German Ministry of Education and Research. Carilli will use the funding to support young researchers and to build scientific instrumentation, with a focus on fostering radio studies of cosmic reionization and the first

  6. Atlas of Astronomical Discoveries

    CERN Document Server

    Schilling, Govert

    2011-01-01

    Four hundred years ago in Middelburg, in the Netherlands, the telescope was invented. The invention unleashed a revolution in the exploration of the universe. Galileo Galilei discovered mountains on the Moon, spots on the Sun, and moons around Jupiter. Christiaan Huygens saw details on Mars and rings around Saturn. William Herschel discovered a new planet and mapped binary stars and nebulae. Other astronomers determined the distances to stars, unraveled the structure of the Milky Way, and discovered the expansion of the universe. And, as telescopes became bigger and more powerful, astronomers delved deeper into the mysteries of the cosmos. In his Atlas of Astronomical Discoveries, astronomy journalist Govert Schilling tells the story of 400 years of telescopic astronomy. He looks at the 100 most important discoveries since the invention of the telescope. In his direct and accessible style, the author takes his readers on an exciting journey encompassing the highlights of four centuries of astronomy. Spectacul...

  7. OLFAR - Orbiting low frequency antennas for radio astronomy

    NARCIS (Netherlands)

    Bentum, Marinus Jan

    2013-01-01

    One of the last unexplored frequency ranges in radio astronomy is the frequency band below 30 MHz. New interesting astronomical science drivers for low frequency radio astronomy have emerged, ranging from studies of the astronomical dark ages, the epoch of reionization, exoplanets, to ultra-high

  8. Spectrum monitoring: Radio Frequency Interferences (RFI) profile for ...

    African Journals Online (AJOL)

    It was crucial to monitor the Radio Frequency Interference (RFI) in order to conduct the radio astronomical research with very minimum RFI. These RFI will be distorted the astronomical data. In this work, we have investigated the RFI strength (dBm) and presenting on how the nearby RFI affect to the OH lines window (1600 ...

  9. Astronomers Use Moon in Effort to Corral Elusive Cosmic Particles

    Science.gov (United States)

    2010-11-01

    Seeking to detect mysterious, ultra-high-energy neutrinos from distant regions of space, a team of astronomers used the Moon as part of an innovative telescope system for the search. Their work gave new insight on the possible origin of the elusive subatomic particles and points the way to opening a new view of the Universe in the future. The team used special-purpose electronic equipment brought to the National Science Foundation's Very Large Array (VLA) radio telescope, and took advantage of new, more-sensitive radio receivers installed as part of the Expanded VLA (EVLA) project. Prior to their observations, they tested their system by flying a small, specialized transmitter over the VLA in a helium balloon. In 200 hours of observations, Ted Jaeger of the University of Iowa and the Naval Research Laboratory, and Robert Mutel and Kenneth Gayley of the University of Iowa did not detect any of the ultra-high-energy neutrinos they sought. This lack of detection placed a new limit on the amount of such particles arriving from space, and cast doubt on some theoretical models for how those neutrinos are produced. Neutrinos are fast-moving subatomic particles with no electrical charge that readily pass unimpeded through ordinary matter. Though plentiful in the Universe, they are notoriously difficult to detect. Experiments to detect neutrinos from the Sun and supernova explosions have used large volumes of material such as water or chlorine to capture the rare interactions of the particles with ordinary matter. The ultra-high-energy neutrinos the astronomers sought are postulated to be produced by the energetic, black-hole-powered cores of distant galaxies; massive stellar explosions; annihilation of dark matter; cosmic-ray particles interacting with photons of the Cosmic Microwave Background; tears in the fabric of space-time; and collisions of the ultra-high-energy neutrinos with lower-energy neutrinos left over from the Big Bang. Radio telescopes can't detect

  10. A refined Astronomically Calibrated 40AR/39Ar age for Fish Canyon Sanidine

    NARCIS (Netherlands)

    Rivera, T.A.; Storey, M.; Zeeden, C.; Hilgen, F.J.; Kuiper, K.F.

    2011-01-01

    Intercalibration between the astronomical and radio-isotopic dating methods provides a means to improving accuracy and reducing uncertainty of an integrated, multi-chronometer geologic timescale. Here we report a high-precision

  11. Methods in Astronomical Image Processing

    Science.gov (United States)

    Jörsäter, S.

    A Brief Introductory Note History of Astronomical Imaging Astronomical Image Data Images in Various Formats Digitized Image Data Digital Image Data Philosophy of Astronomical Image Processing Properties of Digital Astronomical Images Human Image Processing Astronomical vs. Computer Science Image Processing Basic Tools of Astronomical Image Processing Display Applications Calibration of Intensity Scales Calibration of Length Scales Image Re-shaping Feature Enhancement Noise Suppression Noise and Error Analysis Image Processing Packages: Design of AIPS and MIDAS AIPS MIDAS Reduction of CCD Data Bias Subtraction Clipping Preflash Subtraction Dark Subtraction Flat Fielding Sky Subtraction Extinction Correction Deconvolution Methods Rebinning/Combining Summary and Prospects for the Future

  12. BOOK REVIEW: The Wandering Astronomer

    Science.gov (United States)

    Swinbank, Elizabeth

    2000-09-01

    Fans of Patrick Moore will like this book. I enjoyed it more than I expected, having anticipated a collection of personal anecdotes of the type favoured by certain tedious after-dinner speakers. Some of the 41 short items it contains do tend towards that category, but there are also some nuggets which might enliven your physics teaching. For example, did you know that, in a murder trial in 1787, the defendant's belief that the Sun was inhabited was cited as evidence of his insanity? This was despite his views being shared by many astronomers of the day including William Herschel. Or that Clyde Tombaugh had a cat called Pluto after the planet he discovered, which was itself named by an eleven-year-old girl? Another gem concerns a brief flurry, in the early 1990s, over a suspected planet orbiting a pulsar; variations in the arrival time of its radio pulses indicated the presence of an orbiting body. These shifts were later found to arise from an error in a computer program that corrected for the Earth's motion. The programmer had assumed a circular orbit for the Earth whereas it is actually elliptical. The book is clearly intended for amateur astronomers and followers of Patrick Moore's TV programmes. There is plenty of astronomy, with an emphasis on the solar system, but very little astrophysics. The author's metricophobia means that quantities are given in imperial units throughout, with metric equivalents added in brackets (by an editor, I suspect) which can get irritating, particularly as powers-of-ten notation is avoided. It is quite a novelty to see the temperature for hydrogen fusion quoted as 18 000 000 °F (10 000 000 °C). By way of contrast, astronomical terms are used freely - ecliptic, first-magnitude star, and so on. Such terms are defined in a glossary at the end, but attention is not drawn to this and I only stumbled across it by chance. Patrick Moore obviously knows his public, and this book will serve them well. For physics teachers and students

  13. ASURV: Astronomical SURVival Statistics

    Science.gov (United States)

    Feigelson, E. D.; Nelson, P. I.; Isobe, T.; LaValley, M.

    2014-06-01

    ASURV (Astronomical SURVival Statistics) provides astronomy survival analysis for right- and left-censored data including the maximum-likelihood Kaplan-Meier estimator and several univariate two-sample tests, bivariate correlation measures, and linear regressions. ASURV is written in FORTRAN 77, and is stand-alone and does not call any specialized libraries.

  14. Korean Astronomical Calendar, Chiljeongsan

    Science.gov (United States)

    Lee, Eun Hee

    In fifteenth century Korea, there was a grand project for the astronomical calendar and instrument making by the order of King Sejong 世宗 (1418-1450). During this period, many astronomical and calendrical books including Islamic sources in Chinese versions were imported from Ming 明 China, and corrected and researched by the court astronomers of Joseon 朝鮮 (1392-1910). Moreover, the astronomers and technicians of Korea frequently visited China to study astronomy and instrument making, and they brought back useful information in the form of new published books or specifications of instruments. As a result, a royal observatory equipped with 15 types of instrument was completed in 1438. Two types of calendar, Chiljeongsan Naepyeon 七政算內篇 and Chiljeongsan Oepyeon 七政算外篇, based on the Chinese and Islamic calendar systems, respectively, were published in 1444 with a number of calendrical editions such as corrections and example supplements (假令) including calculation methods and results for solar and lunar eclipses.

  15. Genetic programming applied to RFI mitigation in radio astronomy

    Science.gov (United States)

    Staats, K.

    2016-12-01

    Genetic Programming is a type of machine learning that employs a stochastic search of a solutions space, genetic operators, a fitness function, and multiple generations of evolved programs to resolve a user-defined task, such as the classification of data. At the time of this research, the application of machine learning to radio astronomy was relatively new, with a limited number of publications on the subject. Genetic Programming had never been applied, and as such, was a novel approach to this challenging arena. Foundational to this body of research, the application Karoo GP was developed in the programming language Python following the fundamentals of tree-based Genetic Programming described in "A Field Guide to Genetic Programming" by Poli, et al. Karoo GP was tasked with the classification of data points as signal or radio frequency interference (RFI) generated by instruments and machinery which makes challenging astronomers' ability to discern the desired targets. The training data was derived from the output of an observation run of the KAT-7 radio telescope array built by the South African Square Kilometre Array (SKA-SA). Karoo GP, kNN, and SVM were comparatively employed, the outcome of which provided noteworthy correlations between input parameters, the complexity of the evolved hypotheses, and performance of raw data versus engineered features. This dissertation includes description of novel approaches to GP, such as upper and lower limits to the size of syntax trees, an auto-scaling multiclass classifier, and a Numpy array element manager. In addition to the research conducted at the SKA-SA, it is described how Karoo GP was applied to fine-tuning parameters of a weather prediction model at the South African Astronomical Observatory (SAAO), to glitch classification at the Laser Interferometer Gravitational-wave Observatory (LIGO), and to astro-particle physics at The Ohio State University.

  16. New discoveries with radio telescopes

    International Nuclear Information System (INIS)

    Schmidt, J.

    1985-01-01

    The author describes in a simple fashion the results obtained by astronomers from ETH Zurich using the broadband 7-m radio telescope in Switzerland to observe the sun over a period of six years. He explains the results in terms of our present understanding of the sun's workings. The astronomers found that a solar eruption is not a single event but consists of tens of thousands of small eruptions or spikes each only 200 km high and producing a burst of radio waves 10-100 times as intense as the background. (T.J.R.A.)

  17. Young Star May Be Belching Spheres of Gas, Astronomers Say

    Science.gov (United States)

    2001-05-01

    A young star more than 2,000 light-years away in the constellation Cepheus may be belching out spheres of gas, say astronomers who observed it with the National Science Foundation's Very Long Baseline Array (VLBA) radio telescope. Not only is the star ejecting spheres of gas, the researchers say, but it also may be ejecting them repeatedly, phenomena not predicted by current theories of how young stars shed matter. Cepheus A star-forming region with blowups of detail In order to remain stable while accumulating matter, young stars have to throw off some of the infalling material to avoid "spinning up" so fast they would break apart, according to current theories. Infalling matter forms a thin spinning disk around the core of the new star, and material is ejected in twin "jets" perpendicular to the plane of the disk. "Twin jets have been seen emerging from many young stars, so we are quite surprised to see evidence that this object may be ejecting not jets, but spheres of gas," said Paul T.P. Ho, an astronomer at the Harvard-Smithsonian Center for Astrophysics. The research is reported in the May 17 edition of the scientific journal Nature. The astronomers observed a complex star-forming region in Cepheus and found an arc of water molecules that act like giant celestial amplifiers to boost the strength of radio signals at a frequency of 22 GHz. Such radio-wave amplifiers, called masers, show up as bright spots readily observed with radio telescopes. "With the great ability of the VLBA to show fine detail, we could track the motions of these maser spots over a period of weeks, and saw that this arc of water molecules is expanding at nearly 20,000 miles per hour," said Ho. "This was possible because we could detect detail equivalent to seeing Lincoln's nose on a penny in Los Angeles from the distance of New York," Ho added. "These observations pushed the tremendous capabilities of the VLBA and of modern computing power to their limits. This is an extremely complex

  18. Fastest Pulsar Speeding Out of Galaxy, Astronomers Discover

    Science.gov (United States)

    2005-08-01

    A speeding, superdense neutron star somehow got a powerful "kick" that is propelling it completely out of our Milky Way Galaxy into the cold vastness of intergalactic space. Its discovery is puzzling astronomers who used the National Science Foundation's Very Long Baseline Array (VLBA) radio telescope to directly measure the fastest speed yet found in a neutron star. Pulsar's Path Across Sky Over about 2.5 million years, Pulsar B1508+55 has moved across about a third of the night sky as seen from Earth. CREDIT: Bill Saxton, NRAO/AUI/NSF (Click on image for larger version 67 KB) The neutron star is the remnant of a massive star born in the constellation Cygnus that exploded about two and a half million years ago in a titanic explosion known as a supernova. Ultra-precise VLBA measurements of its distance and motion show that it is on course to inevitably leave our Galaxy. "We know that supernova explosions can give a kick to the resulting neutron star, but the tremendous speed of this object pushes the limits of our current understanding," said Shami Chatterjee, of the National Radio Astronomy Observatory (NRAO) and the Harvard-Smithsonian Center for Astrophysics. "This discovery is very difficult for the latest models of supernova core collapse to explain," he added. Chatterjee and his colleagues used the VLBA to study the pulsar B1508+55, about 7700 light-years from Earth. With the ultrasharp radio "vision" of the continent-wide VLBA, they were able to precisely measure both the distance and the speed of the pulsar, a spinning neutron star emitting powerful beams of radio waves. Plotting its motion backward pointed to a birthplace among groups of giant stars in the constellation Cygnus -- stars so massive that they inevitably explode as supernovae. "This is the first direct measurement of a neutron star's speed that exceeds 1,000 kilometers per second," said Walter Brisken, an NRAO astronomer. "Most earlier estimates of neutron-star speeds depended on educated

  19. Astronomers Trace Microquasar's Path Back in Time

    Science.gov (United States)

    2003-01-01

    Astronomers have traced the orbit through our Milky Way Galaxy of a voracious neutron star and a companion star it is cannibalizing, and conclude that the pair joined more than 30 million years ago and probably were catapulted out of a cluster of stars far from the Galaxy's center. Path of Microquasar and Sun Path of Microquasar (red) and Sun (yellow) through the Milky Way Galaxy for the past 230 million years. Animations: GIF Version MPEG Version CREDIT: Mirabel & Rodrigues, NRAO/AUI/NSF The pair of stars, called Scorpius X-1, form a "microquasar," in which material sucked from the "normal" star forms a rapidly-rotating disk around the superdense neutron star. The disk becomes so hot it emits X-rays, and also spits out "jets" of subatomic particles at nearly the speed of light. Using precise positional data from the National Science Foundation's Very Long Baseline Array (VLBA) and from optical telescopes, Felix Mirabel, an astrophysicist at the Institute for Astronomy and Space Physics of Argentina and French Atomic Energy Commission, and Irapuan Rodrigues, also of the French Atomic Energy Commission, calculated that Scorpius X-1 is not orbiting the Milky Way's center in step with most other stars, but instead follows an eccentric path far above and below the Galaxy's plane. Scorpius X-1, discovered with a rocket-borne X-ray telescope in 1962, is about 9,000 light-years from Earth. It is the brightest continuous source of X-rays beyond the Solar System. The 1962 discovery and associated work earned a share of the 2002 Nobel Prize in physics for Riccardo Giacconi. Mirabel and Rodrigues used a number of published observations to calculate the path of Scorpius X-1 over the past few million years. "This is the most accurate determination we have made of the path of an X-ray binary," said Mirabel. By tracing the object's path backward in time, the scientists were able to conclude that the neutron star and its companion have been traveling together for more than 30

  20. Astronomical Spectroscopy for Amateurs

    CERN Document Server

    Harrison, Ken M

    2011-01-01

    Astronomical Spectroscopy for Amateurs is a complete guide for amateur astronomers who are looking for a new challenge beyond astrophotography. The book provides a brief overview of the history and development of the spectroscope, then a short introduction to the theory of stellar spectra, including details on the necessary reference spectra required for instrument testing and spectral comparison. The various types of spectroscopes available to the amateur are then described. Later sections cover all aspects of setting up and using various types of commercially available and home-built spectroscopes, starting with basic transmission gratings and going through more complex models, all the way to the sophisticated Littrow design. The final part of the text is about practical spectroscope design and construction. This book uniquely brings together a collection of observing, analyzing, and processing hints and tips that will allow the amateur to build skills in preparing scientifically acceptable spectra data. It...

  1. South African Astronomical Observatory

    International Nuclear Information System (INIS)

    1987-01-01

    Work at the South African Astronomical Observatory (SAAO) in recent years, by both staff and visitors, has made major contributions to the fields of astrophysics and astronomy. During 1986 the SAAO has been involved in studies of the following: galaxies; celestial x-ray sources; magellanic clouds; pulsating variables; galactic structure; binary star phenomena; nebulae and interstellar matter; stellar astrophysics; open clusters; globular clusters, and solar systems

  2. Astronomical Research Using Virtual Observatories

    Directory of Open Access Journals (Sweden)

    M Tanaka

    2010-01-01

    Full Text Available The Virtual Observatory (VO for Astronomy is a framework that empowers astronomical research by providing standard methods to find, access, and utilize astronomical data archives distributed around the world. VO projects in the world have been strenuously developing VO software tools and/or portal systems. Interoperability among VO projects has been achieved with the VO standard protocols defined by the International Virtual Observatory Alliance (IVOA. As a result, VO technologies are now used in obtaining astronomical research results from a huge amount of data. We describe typical examples of astronomical research enabled by the astronomical VO, and describe how the VO technologies are used in the research.

  3. The Spectrum Landscape: Prospects for Terrestrial Radio Astronomy

    Science.gov (United States)

    Liszt, Harvey Steven

    2018-01-01

    Radio astronomers work within broad constraints imposed by commercial and other non-astronomical uses of the radio spectrum, somewhat modified to accommodate astronomy’s particular needs through the provision of radio quiet zones, radio frequency allocations, coordination agreements and other devices of spectrum management. As radio astronomers increase the instantaneous bandwidth, frequency coverage and sensitivity of their instruments, these external constraints, and not the limitations of their own instruments, will increasingly be the greatest obstacles to radio astronomy’s ability to observe the cosmos from the surface of the Earth. Therefore, prospects for future radio astronomy operations are contingent on situational awareness and planning for the impact of non-astronomical uses of the radio frequency spectrum. New radio astronomy instruments will have to incorporate adaptive reactions to external developments, and radio astronomers should be encouraged to think in untraditional ways. Increased attention to spectrum management is one of these. In this talk I’ll recap some recent developments such as the proliferation of 76 – 81 GHz car radar and orbiting earth-mapping radars, either of which can burn out a radio astronomy receiver. I’ll summarize present trends for non-astronomical radio spectrum use that will be coming to fruition in the next decade or so, categorized into terrestrial fixed and mobile, airborne and space-borne uses, sub-divided by waveband from the cm to the sub-mm. I’ll discuss how they will impact terrestrial radio astronomy and the various ways in which radio astronomy should be prepared to react. Protective developments must occur both within radio astronomy’s own domain – designing, siting and constructing its instruments and mitigating unavoidable RFI – and facing outward toward the community of other spectrum users. Engagement with spectrum management is no panacea but it is an important means, and perhaps the only

  4. Historic Radio Astronomy Working Group

    Science.gov (United States)

    2007-06-01

    This special issue of Astronomische Nachrichten contains the proceedings of a session of the Historic Radio Astronomy Working Group of the International Astronomical Union that took place during the 26th General Assembly of the IAU in Prague on 17th August 2006. In addition to the talks presented in Prague some contributions were solicited to give a more complete overview of `The Early History of European Radio Astronomy'.

  5. Large Astronomical Surveys, Catalogs and Databases

    Directory of Open Access Journals (Sweden)

    Mickaelian A. M.

    2012-09-01

    Full Text Available We review the status of all-sky and large astronomical surveys and their catalogued data over the whole range of electromagnetic spectrum, from gamma-ray to radio, such as ROSAT in X-ray, GALEX in UV, SDSS and several POSS1/2 based catalogs (APM, MAPS, USNO, GSC in optical, 2MASS and WISE in NIR, IRAS and AKARI in MIR/FIR, NVSS and FIRST in radio range and others. Present astronomical archives contain billions of objects, Galactic as well as extragalactic, and the vast amount of data in them permit new studies and discoveries. Cross-correlations result in revealing new objects and new samples. Very often, dozens of thousands of sources hide a few very interesting ones that are needed to be discovered by comparison of various physical characteristics. Most of the modern databases currently provide VO access to the stored information. This permits not only open access but also fast analysis and managing of these data.

  6. On astronomical drawing [1846

    Science.gov (United States)

    Smyth, Charles Piazzi

    Reprinted from the Memoirs of the Royal Astronomical Society 15, 1846, pp. 71-82. With annotations and illustrations added by Klaus Hentschel. The activities of the Astronomer Royal for Scotland, Charles Piazzi Smyth (1819-1900), include the triangulation of South African districts, landscape painting, day-to-day or tourist sketching, the engraving and lithographing of prominent architectural sites, the documentary photography of the Egyptian pyramids or the Tenerife Dragon tree, and `instant photographs' of the clouds above his retirement home in Clova, Ripon. His colorful records of the aurora polaris, and solar and terrestrial spectra all profited from his trained eye and his subtle mastery of the pen and the brush. As his paper on astronomical drawing, which we chose to reproduce in this volume, amply demonstrates, he was conversant in most of the print technology repertoire that the 19th century had to offer, and carefully selected the one most appropriate to each sujet. For instance, he chose mezzotint for the plates illustrating Maclear's observations of Halley's comet in 1835/36, so as to achieve a ``rich profundity of shadows, the deep obscurity of which is admirably adapted to reproduce those fine effects of chiaroscuro frequently found in works where the quantity of dark greatly predominates.'' The same expertise with which he tried to emulate Rembrandt's chiaroscuro effects he applied to assessing William and John Herschel's illustrations of nebulae, which appeared in print between 1811 and 1834. William Herschel's positive engraving, made partly by stippling and partly by a coarse mezzotint, receives sharp admonishment because of the visible ruled crossed lines in the background and the fact that ``the objects, which are also generally too light, [have] a much better definition than they really possess.'' On the other hand, John Herschel's illustration of nebulae and star clusters, given in negative, ``in which the lights are the darkest part of the

  7. Astronomical Instruments in India

    Science.gov (United States)

    Sarma, Sreeramula Rajeswara

    The earliest astronomical instruments used in India were the gnomon and the water clock. In the early seventh century, Brahmagupta described ten types of instruments, which were adopted by all subsequent writers with minor modifications. Contact with Islamic astronomy in the second millennium AD led to a radical change. Sanskrit texts began to lay emphasis on the importance of observational instruments. Exclusive texts on instruments were composed. Islamic instruments like the astrolabe were adopted and some new types of instruments were developed. Production and use of these traditional instruments continued, along with the cultivation of traditional astronomy, up to the end of the nineteenth century.

  8. Grigor Narekatsi's astronomical insights

    Science.gov (United States)

    Poghosyan, Samvel

    2015-07-01

    What stand out in the solid system of Gr. Narekatsi's naturalistic views are his astronomical insights on the material nature of light, its high speed and the Sun being composed of "material air". Especially surprising and fascinating are his views on stars and their clusters. What astronomers, including great Armenian academician V. Ambartsumian (scattering of stellar associations), would understand and prove with much difficulty thousand years later, Narekatsi predicted in the 10th century: "Stars appear and disappear untimely", "You who gather and scatter the speechless constellations, like a flock of sheep". Gr. Narekatsti's reformative views were manifested in all the spheres of the 10th century social life; he is a reformer of church life, great language constructor, innovator in literature and music, freethinker in philosophy and science. His ideology is the reflection of the 10th century Armenian Renaissance. During the 9th-10th centuries, great masses of Armenians, forced to migrate to the Balkans, took with them and spread reformative ideas. The forefather of the western science, which originated in the period of Reformation, is considered to be the great philosopher Nicholas of Cusa. The study of Gr. Narekatsti's logic and naturalistic views enables us to claim that Gr. Narekatsti is the great grandfather of European science.

  9. Getting Astronomers Involved in the IYA: Astronomer in the Classroom

    Science.gov (United States)

    Koenig, Kris

    2008-05-01

    The Astronomer in the Classroom program provides professional astronomers the opportunity to engage with 3rd-12th grade students across the nation in grade appropriate discussions of their recent research, and provides students with rich STEM content in a personalized forum, bringing greater access to scientific knowledge for underserved populations. 21st Century Learning and Interstellar Studios, the producer of the 400 Years of the Telescope documentary along with their educational partners, will provide the resources necessary to facilitate the Astronomer in the Classroom program, allowing students to interact with astronomers throughout the IYA2009. PROGRAM DESCRIPTION One of hundreds of astronomers will be available to interact with students via live webcast daily during Spring/Fall 2009. The astronomer for the day will conduct three 20-minute discussions (Grades 3-5 /6-8/9-12), beginning with a five-minute PowerPoint on their research or area of interest. The discussion will be followed by a question and answer period. The students will participate in real-time from their school computer(s) with the technology provided by 21st Century Learning. They will see and hear the astronomer on their screen, and pose questions from their keyboard. Teachers will choose from three daily sessions; 11:30 a.m., 12:00 p.m., 12:30 p.m. Eastern Time. This schedule overlaps all US time zones, and marginalizes bandwidth usage, preventing technological barriers to web access. The educational partners and astronomers will post materials online, providing easy access to information that will prepare teachers and students for the chosen discussion. The astronomers, invited to participate from the AAS and IAU, will receive a web cam shipment with instructions, a brief training and conductivity test, and prepaid postage for shipment of the web cam to the next astronomer on the list. The anticipated astronomer time required is 3-hours, not including the time to develop the PowerPoint.

  10. The importance of Radio Quiet Zone (RQZ) for radio astronomy

    Science.gov (United States)

    Umar, Roslan; Abidin, Zamri Zainal; Ibrahim, Zainol Abidin

    2013-05-01

    Most of radio observatories are located in isolated areas. Since radio sources from the universe is very weak, astronomer need to avoid radio frequency interference (RFI) from active spectrum users and radio noise produced by human made (telecommunication, mobile phone, microwave user and many more. There are many observatories around the world are surrounded by a Radio Quiet Zone (RQZ), which is it was set up using public or state laws. A Radio Quiet Zone normally consists of two areas: an exclusive area in which totally radio emissions are forbidden, with restrictions for residents and business developments, and a larger (radius up to 100 km above) coordination area where the power of radio transmission limits to threshold levels. Geographical Information System (GIS) can be used as a powerful tool in mapping large areas with varying RQZ profiles. In this paper, we report the initial testing of the usage of this system in order to identify the areas were suitable for Radio Quiet Zone. Among the important parameters used to develop the database for our GIS are population density, information on TV and telecommunication (mobile phones) transmitters, road networks (highway), and contour shielding. We will also use other information gathered from on-site RFI level measurements on selected 'best' areas generated by the GIS. The intention is to find the best site for the purpose of establishing first radio quiet zones for radio telescope in Malaysia.

  11. Continent-Spanning Radio Telescope Blazes Trails At the Frontiers of Astrophysics

    Science.gov (United States)

    1999-06-01

    The supersharp radio "vision" of the National Science Foundation's (NSF) Very Long Baseline Array (VLBA) is revealing unprecedented details of astronomical objects from stars in our own cosmic neighborhood to galaxies billions of light-years away. Astronomers from across North America and beyond are presenting the results of VLBA research at the American Astronomical Society's (AAS) meeting in Chicago. "The VLBA is one of the most powerful tools in the world for astronomy," said Paul Vanden Bout, Director of the National Radio Astronomy Observatory (NRAO), which operates the VLBA. "It can produce images hundreds of times more detailed than those produced by the Hubble Space Telescope, and that capability has yielded some spectacular scientific results." Examples of VLBA research presented at the AAS meeting include the most accurate measurement ever made of the distance to another galaxy; the detection of our Solar System's orbital motion around the center of our own Galaxy; a "movie" showing the expansion of debris from a star's explosion in a galaxy 11 million light-years away; and a "movie" of gas motions in the atmosphere of a star more than 1,000 light-years away -- the first time gas motions have ever been tracked in a star other than the Sun. With ten giant dish antennas spread from Hawaii in the Pacific to St. Croix in the Caribbean, all working together as a single telescope, the VLBA is "the world's biggest astronomical instrument," Vanden Bout said. The VLBA has been in full operation for more than five years. A pair of sessions at the AAS meeting is devoted to reports of research using the VLBA. In more than 40 scientific presentations, astronomers tell how they used the VLBA to gain valuable new information about nearly every area from the frontiers of astrophysics. Some of those reporting on their VLBA research are graduate students working on their Ph.D degrees. "We are particularly proud that this instrument, one of the world's premier facilities

  12. Radio Telescopes Reveal Unseen Galactic Cannibalism

    Science.gov (United States)

    2008-06-01

    Radio-telescope images have revealed previously-unseen galactic cannibalism -- a triggering event that leads to feeding frenzies by gigantic black holes at the cores of galaxies. Astronomers have long suspected that the extra-bright cores of spiral galaxies called Seyfert galaxies are powered by supermassive black holes consuming material. However, they could not see how the material is started on its journey toward the black hole. Optical/Radio Comparison Visible-light (left) and radio (right) image of galaxy pair: Radio image shows gas streaming between galaxies. CREDIT: Kuo et al., NRAO/AUI/NSF Click on image for more graphics. One leading theory said that Seyfert galaxies have been disturbed by close encounters with neighboring galaxies, thus stirring up their gas and bringing more of it within the gravitational reach of the black hole. However, when astronomers looked at Seyferts with visible-light telescopes, only a small fraction showed any evidence of such an encounter. Now, new images of hydrogen gas in Seyferts made using the National Science Foundation's Very Large Array (VLA) radio telescope show the majority of them are, in fact, disturbed by ongoing encounters with neighbor galaxies. "The VLA lifted the veil on what's really happening with these galaxies," said Cheng-Yu Kuo, a graduate student at the University of Virginia. "Looking at the gas in these galaxies clearly showed that they are snacking on their neighbors. This is a dramatic contrast with their appearance in visible starlight," he added. The effect of the galactic encounters is to send gas and dust toward the black hole and produce energy as the material ultimately is consumed. Black holes, concentrations of matter so dense that not even light can escape their gravitational pull, reside at the cores of many galaxies. Depending on how rapidly the black hole is eating, the galaxy can show a wide range of energetic activity. Seyfert galaxies have the mildest version of this activity, while

  13. The Next-Generation Very Large Array: Technical Overview

    Science.gov (United States)

    McKinnon, Mark; Selina, Rob

    2018-01-01

    As part of its mandate as a national observatory, the NRAO is looking toward the long range future of radio astronomy and fostering the long term growth of the US astronomical community. NRAO has sponsored a series of science and technical community meetings to consider the science mission and design of a next-generation Very Large Array (ngVLA), building on the legacies of the Atacama Large Millimeter/submillimeter Array (ALMA) and the Very Large Array (VLA).The basic ngVLA design emerging from these discussions is an interferometric array with approximately ten times the sensitivity and ten times higher spatial resolution than the VLA and ALMA radio telescopes, optimized for operation in the wavelength range 0.3cm to 3cm. The ngVLA would open a new window on the Universe through ultra-sensitive imaging of thermal line and continuum emission down to milli-arcsecond resolution, as well as unprecedented broadband continuum polarimetric imaging of non-thermal processes. The specifications and concepts for major ngVLA system elements are rapidly converging.We will provide an overview of the current system design of the ngVLA. The concepts for major system elements such as the antenna, receiving electronics, and central signal processing will be presented. We will also describe the major development activities that are presently underway to advance the design.

  14. Astronomical dating in the 19th century

    Science.gov (United States)

    Hilgen, Frederik J.

    2010-01-01

    Today astronomical tuning is widely accepted as numerical dating method after having revolutionised the age calibration of the geological archive and time scale over the last decades. However, its origin is not well known and tracing its roots is important especially from a science historic perspective. Astronomical tuning developed in consequence of the astronomical theory of the ice ages and was repeatedly used in the second half of the 19th century before the invention of radio-isotopic dating. Building upon earlier ideas of Joseph Adhémar, James Croll started to formulate his astronomical theory of the ice ages in 1864 according to which precession controlled ice ages occur alternatingly on both hemispheres at times of maximum eccentricity of the Earth's orbit. The publication of these ideas compelled Charles Lyell to revise his Principles of Geology and add Croll's theory, thus providing an alternative to his own geographical cause of the ice ages. Both Croll and Lyell initially tuned the last glacial epoch to the prominent eccentricity maximum 850,000 yr ago. This age was used as starting point by Lyell to calculate an age of 240 million years for the beginning of the Cambrium. But Croll soon revised the tuning to a much younger less prominent eccentricity maximum between 240,000 and 80,000 yr ago. In addition he tuned older glacial deposits of late Miocene and Eocene ages to eccentricity maxima around 800,000 and 2,800,000 yr ago. Archibald and James Geikie were the first to recognize interglacials during the last glacial epoch, as predicted by Croll's theory, and attempted to tune them to precession. Soon after Frank Taylor linked a series of 15 end-moraines left behind by the retreating ice sheet to precession to arrive at a possible age of 300,000 yr for the maximum glaciation. In a classic paper, Axel Blytt (1876) explained the scattered distribution of plant groups in Norway to precession induced alternating rainy and dry periods as recorded by the

  15. The Star Formation in Radio Survey: Jansky Very Large Array 33 GHz Observations of Nearby Galaxy Nuclei and Extranuclear Star-forming Regions

    Science.gov (United States)

    Murphy, E. J.; Dong, D.; Momjian, E.; Linden, S.; Kennicutt, R. C., Jr.; Meier, D. S.; Schinnerer, E.; Turner, J. L.

    2018-02-01

    We present 33 GHz imaging for 112 pointings toward galaxy nuclei and extranuclear star-forming regions at ≈2″ resolution using the Karl G. Jansky Very Large Array (VLA) as part of the Star Formation in Radio Survey. A comparison with 33 GHz Robert C. Byrd Green Bank Telescope single-dish observations indicates that the interferometric VLA observations recover 78% ± 4% of the total flux density over 25″ regions (≈kpc scales) among all fields. On these scales, the emission being resolved out is most likely diffuse non-thermal synchrotron emission. Consequently, on the ≈30–300 pc scales sampled by our VLA observations, the bulk of the 33 GHz emission is recovered and primarily powered by free–free emission from discrete H II regions, making it an excellent tracer of massive star formation. Of the 225 discrete regions used for aperture photometry, 162 are extranuclear (i.e., having galactocentric radii r G ≥ 250 pc) and detected at >3σ significance at 33 GHz and in Hα. Assuming a typical 33 GHz thermal fraction of 90%, the ratio of optically-thin 33 GHz to uncorrected Hα star formation rates indicates a median extinction value on ≈30–300 pc scales of A Hα ≈ 1.26 ± 0.09 mag, with an associated median absolute deviation of 0.87 mag. We find that 10% of these sources are “highly embedded” (i.e., A Hα ≳ 3.3 mag), suggesting that on average, H II regions remain embedded for ≲1 Myr. Finally, we find the median 33 GHz continuum-to-Hα line flux ratio to be statistically larger within r G < 250 pc relative to the outer disk regions by a factor of 1.82 ± 0.39, while the ratio of 33 GHz to 24 μm flux densities is lower by a factor of 0.45 ± 0.08, which may suggest increased extinction in the central regions.

  16. Astronomer's new guide to the galaxy: largest map of cold dust revealed

    Science.gov (United States)

    2009-07-01

    Astronomers have unveiled an unprecedented new atlas of the inner regions of the Milky Way, our home galaxy, peppered with thousands of previously undiscovered dense knots of cold cosmic dust -- the potential birthplaces of new stars. Made using observations from the APEX telescope in Chile, this survey is the largest map of cold dust so far, and will prove an invaluable map for observations made with the forthcoming ALMA telescope, as well as the recently launched ESA Herschel space telescope. ESO PR Photo 24a/09 View of the Galactic Plane from the ATLASGAL survey (annotated and in five sections) ESO PR Photo 24b/09 View of the Galactic Plane from the ATLASGAL survey (annotated) ESO PR Photo 24c/09 View of the Galactic Plane from the ATLASGAL survey (in five sections) ESO PR Photo 24d/09 View of the Galactic Plane from the ATLASGAL survey ESO PR Photo 24e/09 The Galactic Centre and Sagittarius B2 ESO PR Photo 24f/09 The NGC 6357 and NGC 6334 nebulae ESO PR Photo 24g/09 The RCW120 nebula ESO PR Video 24a/09 Annotated pan as seen by the ATLASGAL survey This new guide for astronomers, known as the APEX Telescope Large Area Survey of the Galaxy (ATLASGAL) shows the Milky Way in submillimetre-wavelength light (between infrared light and radio waves [1]). Images of the cosmos at these wavelengths are vital for studying the birthplaces of new stars and the structure of the crowded galactic core. "ATLASGAL gives us a new look at the Milky Way. Not only will it help us investigate how massive stars form, but it will also give us an overview of the larger-scale structure of our galaxy", said Frederic Schuller from the Max Planck Institute for Radio Astronomy, leader of the ATLASGAL team. The area of the new submillimetre map is approximately 95 square degrees, covering a very long and narrow strip along the galactic plane two degrees wide (four times the width of the full Moon) and over 40 degrees long. The 16 000 pixel-long map was made with the LABOCA submillimetre

  17. PRIFIRA: General regularization using prior-conditioning for fast radio interferometric imaging†

    Science.gov (United States)

    Naghibzadeh, Shahrzad; van der Veen, Alle-Jan

    2018-06-01

    Image formation in radio astronomy is a large-scale inverse problem that is inherently ill-posed. We present a general algorithmic framework based on a Bayesian-inspired regularized maximum likelihood formulation of the radio astronomical imaging problem with a focus on diffuse emission recovery from limited noisy correlation data. The algorithm is dubbed PRIor-conditioned Fast Iterative Radio Astronomy (PRIFIRA) and is based on a direct embodiment of the regularization operator into the system by right preconditioning. The resulting system is then solved using an iterative method based on projections onto Krylov subspaces. We motivate the use of a beamformed image (which includes the classical "dirty image") as an efficient prior-conditioner. Iterative reweighting schemes generalize the algorithmic framework and can account for different regularization operators that encourage sparsity of the solution. The performance of the proposed method is evaluated based on simulated one- and two-dimensional array arrangements as well as actual data from the core stations of the Low Frequency Array radio telescope antenna configuration, and compared to state-of-the-art imaging techniques. We show the generality of the proposed method in terms of regularization schemes while maintaining a competitive reconstruction quality with the current reconstruction techniques. Furthermore, we show that exploiting Krylov subspace methods together with the proper noise-based stopping criteria results in a great improvement in imaging efficiency.

  18. Antenna design and implementation for the future space Ultra-Long wavelength radio telescope

    Science.gov (United States)

    Chen, Linjie; Aminaei, Amin; Gurvits, Leonid I.; Wolt, Marc Klein; Pourshaghaghi, Hamid Reza; Yan, Yihua; Falcke, Heino

    2018-04-01

    In radio astronomy, the Ultra-Long Wavelengths (ULW) regime of longer than 10 m (frequencies below 30 MHz), remains the last virtually unexplored window of the celestial electromagnetic spectrum. The strength of the science case for extending radio astronomy into the ULW window is growing. However, the opaqueness of the Earth's ionosphere makes ULW observations by ground-based facilities practically impossible. Furthermore, the ULW spectrum is full of anthropogenic radio frequency interference (RFI). The only radical solution for both problems is in placing an ULW astronomy facility in space. We present a concept of a key element of a space-borne ULW array facility, an antenna that addresses radio astronomical specifications. A tripole-type antenna and amplifier are analysed as a solution for ULW implementation. A receiver system with a low power dissipation is discussed as well. The active antenna is optimized to operate at the noise level defined by the celestial emission in the frequency band 1 - 30 MHz. Field experiments with a prototype tripole antenna enabled estimates of the system noise temperature. They indicated that the proposed concept meets the requirements of a space-borne ULW array facility.

  19. Closing remarks: astronomical

    International Nuclear Information System (INIS)

    Pecker, J.-C.

    1990-01-01

    During the discussions we have covered many facets of the basic interactions between solar activity and the Earth's climate. Solar activity is not the only astronomical or astrophysical phenomenon to influence physical conditions in the biosphere. Over timescales an order of magnitude less, the location of the Solar System in the Galaxy may have influenced life on Earth. The Sun is a complex generator of radiation, particles and magnetic fields sent far into space. Even if the total radiation emitted is constant, the amount of radiation received by the Earth changes with time: this change is complex and involved with a redistribution of energy emitted at different solar latitudes than to a real change in solar luminosity. These changes in the Earth's illumination may be a function of the wavelength, and have various effects in different layers of the Earth's atmosphere. The Sun also emits particles of all energies. Some of them find their way through the magnetopause, giving rise to auroras, to magnetic storms, to ionospheric disturbances and the like. The possible climatological effects are yet obscure. To understand the solar terrestrial relations better, regular, routine observations from ground-based stations and from space of solar phenomena must be continued. The sensitivity of human life to small changes in climatic conditions is very large. A good knowledge of solar-physics is therefore important and relevant. (author)

  20. Primena metode MUSIC za određivanje smera dolaska radio-signala korišćenjem antenskih nizova ADCOCK / Application of the MUSIC method for direction of arrival estimation using the ADCOCK antenna arrays

    Directory of Open Access Journals (Sweden)

    Miljko M. Erić

    2002-01-01

    Full Text Available Analiziran je problem procene smera dolaska radio-signala metodom MUSIC korišćenjem antenskih nizova ADCOCK. Formulisan je matematički model signala na antenskom nizu ADCOCK. Izvedene su relacije između vektora prostiranja ADCOCK i vektora prostiranja ukupnog antenskog niza (niza od koga se ADCOCK-ov niz formira. Definisana je kriterijumska funkcija algoritma MUSIC i funkcija neodređenosti antenskog niza ADCOCK. Prikazani su rezultati simulacije, kao i rezultati praktične verifikacije mogućnosti primene metode MUSIC na antenske nizove ADCOCK. / The MUSIC based Direction of Arrival estimation using the ADCOCK antenna arrays is considered. Starting from signal model formulation, the cost function of the MUSIC algorithm and the ambiguity functions for the ADCOCK antenna array have been formulated. Some simulation results and some preliminary results of the verification in practice are presented.

  1. Radio Telescopes Reveal Youngest Stellar Corpse

    Science.gov (United States)

    2004-06-01

    Astronomers using a global combination of radio telescopes to study a stellar explosion some 30 million light-years from Earth have likely discovered either the youngest black hole or the youngest neutron star known in the Universe. Their discovery also marks the first time that a black hole or neutron star has been found associated with a supernova that has been seen to explode since the invention of the telescope nearly 400 years ago. M51 An artist's impression of Supernova 1986J. The newly discovered nebula around the black hole or neutron star in the center is shown in blue, and is in the center of the expanding, fragmented shell of material thrown off in the supernova explosion, which is shown in red. CREDIT: Norbert Bartel and Michael F. Bietenholz, York University; Artist: G. Arguner (Click on image for larger version) Image Files Artist's Conception (above image, 836K) Galaxy and Supernova (47K) A VLA image (left) of the galaxy NGC 891, showing the bright supernova explosion below the galaxy's center. At right, a closer view of the supernova, made with a global array of radio telescopes. CREDIT: Miguel A. Perez-Torres, Antxon Alberdi and Lucas Lara, Instituto de Astrofisica de Andalucia - CSIC, Spain, Jon Marcaide and Jose C. Guirado, Universidad de Valencia, Spain Franco Mantovani, IRA-CNR, Italy, Eduardo Ros, MPIfR, Germany, and Kurt W. Weiler, Naval Research Laboratory, USA Multi-Frequency Closeup View (201K) Blue and white area shows the nebula surrounding the black hole or neutron star lurking in the center of the supernova. This nebula is apparent at a higher radio frequency (15 GHz). The red and also the contours show the distorted, expanding shell of material thrown off in the supernova explosion. This shell is seen at a lower radio frequency (5 GHz). CREDIT: Michael F. Bietenholz and Norbert Bartel, York University, Michael Rupen, NRAO, NRAO/AUI/NSF A supernova is the explosion of a massive star after it exhausts its supply of nuclear fuel and

  2. LIMITS ON THE EVENT RATES OF FAST RADIO TRANSIENTS FROM THE V-FASTR EXPERIMENT

    International Nuclear Information System (INIS)

    Wayth, Randall B.; Tingay, Steven J.; Deller, Adam T.; Brisken, Walter F.; Thompson, David R.; Wagstaff, Kiri L.; Majid, Walid A.

    2012-01-01

    We present the first results from the V-FASTR experiment, a commensal search for fast transient radio bursts using the Very Long Baseline Array (VLBA). V-FASTR is unique in that the widely spaced VLBA antennas provide a discriminant against non-astronomical signals and a mechanism for the localization and identification of events that is not possible with single dishes or short baseline interferometers. Thus, far V-FASTR has accumulated over 1300 hr of observation time with the VLBA, between 90 cm and 3 mm wavelength (327 MHz-86 GHz), providing the first limits on fast transient event rates at high radio frequencies (>1.4 GHz). V-FASTR has blindly detected bright individual pulses from seven known pulsars but has not detected any single-pulse events that would indicate high-redshift impulsive bursts of radio emission. At 1.4 GHz, V-FASTR puts limits on fast transient event rates comparable with the PALFA survey at the Arecibo telescope, but generally at lower sensitivities, and comparable to the 'fly's eye' survey at the Allen Telescope Array, but with less sky coverage. We also illustrate the likely performance of the Phase 1 SKA dish array for an incoherent fast transient search fashioned on V-FASTR.

  3. Using commercial amateur astronomical spectrographs

    CERN Document Server

    Hopkins, Jeffrey L

    2014-01-01

    Amateur astronomers interested in learning more about astronomical spectroscopy now have the guide they need. It provides detailed information about how to get started inexpensively with low-resolution spectroscopy, and then how to move on to more advanced  high-resolution spectroscopy. Uniquely, the instructions concentrate very much on the practical aspects of using commercially-available spectroscopes, rather than simply explaining how spectroscopes work. The book includes a clear explanation of the laboratory theory behind astronomical spectrographs, and goes on to extensively cover the practical application of astronomical spectroscopy in detail. Four popular and reasonably-priced commercially available diffraction grating spectrographs are used as examples. The first is a low-resolution transmission diffraction grating, the Star Analyser spectrograph. The second is an inexpensive fiber optic coupled bench spectrograph that can be used to learn more about spectroscopy. The third is a newcomer, the ALPY ...

  4. Astronomical databases of Nikolaev Observatory

    Science.gov (United States)

    Protsyuk, Y.; Mazhaev, A.

    2008-07-01

    Several astronomical databases were created at Nikolaev Observatory during the last years. The databases are built by using MySQL search engine and PHP scripts. They are available on NAO web-site http://www.mao.nikolaev.ua.

  5. Astronomical Instrumentation System Markup Language

    Science.gov (United States)

    Goldbaum, Jesse M.

    2016-05-01

    The Astronomical Instrumentation System Markup Language (AISML) is an Extensible Markup Language (XML) based file format for maintaining and exchanging information about astronomical instrumentation. The factors behind the need for an AISML are first discussed followed by the reasons why XML was chosen as the format. Next it's shown how XML also provides the framework for a more precise definition of an astronomical instrument and how these instruments can be combined to form an Astronomical Instrumentation System (AIS). AISML files for several instruments as well as one for a sample AIS are provided. The files demonstrate how AISML can be utilized for various tasks from web page generation and programming interface to instrument maintenance and quality management. The advantages of widespread adoption of AISML are discussed.

  6. The South African astronomical observatory

    International Nuclear Information System (INIS)

    Feast, M.

    1985-01-01

    A few examples of the activities of the South African Astronomical Observatory are discussed. This includes the studying of stellar evolution, dust around stars, the determination of distances to galaxies and collaboration with space experiments

  7. Sixteenth Century Astronomical Telescopy

    Science.gov (United States)

    Usher, P. D.

    2001-12-01

    Ophelia in Shakespeare's Hamlet is named for the ``moist star" which in mythology is the partner of Hamlet's royal Sun. Together the couple seem destined to rule on earth just as their celestial counterparts rule the heavens, but the tragedy is that they are afflicted, just as the Sun and Moon are blemished. In 1.3 Laertes lectures Ophelia on love and chastity, describing first Cytherean phases (crescent to gibbous) and then Lunar craters. Spots mar the Sun (1.1, 3.1). Also reported are Jupiter's Red Spot (3.4) and the resolution of the Milky Way into stars (2.2). These interpretations are well-founded and support the cosmic allegory. Observations must have been made with optical aid, probably the perspective glass of Leonard Digges, father of Thomas Digges. Notably absent from Hamlet is mention of the Galilean moons, owing perhaps to the narrow field-of-view of the telescope. That discovery is later celebrated in Cymbeline, published soon after Galileo's Siderius Nuncius in 1610. In 5.4 of Cymbeline the four ghosts dance ``in imitation of planetary motions" and at Jupiter's behest place a book on the chest of Posthumus Leonatus. His name identifies the Digges father and son as the source of data in Hamlet since Jupiter's moons were discovered after the deaths of Leonard (``leon+hart") and Thomas (the ``lion's whelp"). Lines in 5.4 urge us not to read more into the book than is contained between its covers; this is understandable because Hamlet had already reported the other data in support of heliocentricism and the cosmic model discussed and depicted by Thomas Digges in 1576. I conclude therefore that astronomical telescopy began in England before the last quarter of the sixteenth century.

  8. Discovery of H I gas in a young radio galaxy at z = 0.44 using the Australian Square Kilometre Array Pathfinder

    NARCIS (Netherlands)

    Allison, J. R.; Sadler, E. M.; Moss, V. A.; Whiting, M. T.; Hunstead, R. W.; Pracy, M. B.; Curran, S. J.; Croom, S. M.; Glowacki, M.; Morganti, R.; Shabala, S. S.; Zwaan, M. A.; Allen, G.; Amy, S. W.; Axtens, P.; Ball, L.; Bannister, K. W.; Barker, S.; Bell, M. E.; Bock, D. C.-J.; Bolton, R.; Bowen, M.; Boyle, B.; Braun, R.; Broadhurst, S.; Brodrick, D.; Brothers, M.; Brown, A.; Bunton, J. D.; Cantrall, C.; Chapman, J.; Cheng, W.; Chippendale, A. P.; Chung, Y.; Cooray, F.; Cornwell, T.; DeBoer, D.; Diamond, P.; Edwards, P. G.; Ekers, R.; Feain, I.; Ferris, R. H.; Forsyth, R.; Gough, R.; Grancea, A.; Gupta, N.; Guzman, J. C.; Hampson, G.; Harvey-Smith, L.; Haskins, C.; Hay, S.; Hayman, D. B.; Heywood, I.; Hotan, A. W.; Hoyle, S.; Humphreys, B.; Indermuehle, B. T.; Jacka, C.; Jackson, C.; Jackson, S.; Jeganathan, K.; Johnston, S.; Joseph, J.; Kendall, R.; Kesteven, M.; Kiraly, D.; Koribalski, B. S.; Leach, M.; Lenc, E.; Lensson, E.; Mackay, S.; Macleod, A.; Marquarding, M.; Marvil, J.; McClure-Griffiths, N.; McConnell, D.; Mirtschin, P.; Norris, R. P.; Neuhold, S.; Ng, A.; O'Sullivan, J.; Pathikulangara, J.; Pearce, S.; Phillips, C.; Popping, A.; Qiao, R. Y.; Reynolds, J. E.; Roberts, P.; Sault, R. J.; Schinckel, A.; Serra, P.; Shaw, R.; Shields, M.; Shimwell, T.; Storey, M.; Sweetnam, T.; Troup, E.; Turner, B.; Tuthill, J.; Tzioumis, A.; Voronkov, M. A.; Westmeier, T.; Wilson, C. D.

    2015-01-01

    We report the discovery of a new 21-cm H I absorption system using commissioning data from the Boolardy Engineering Test Array of the Australian Square Kilometre Array Pathfinder (ASKAP). Using the 711.5-1015.5 MHz band of ASKAP we were able to conduct a blind search for the 21-cm line in a

  9. Enthusiastic Little Astronomers

    Science.gov (United States)

    Novak, Ines

    2016-04-01

    Younger primary school students often show great interest in the vast Universe hiding behind the starry night's sky, but don't have a way of learning about it and exploring it in regular classes. Some of them would search children's books, Internet or encyclopedias for information or facts they are interested in, but there are those whose hunger for knowledge would go unfulfilled. Such students were the real initiators of our extracurricular activity called Little Astronomers. With great enthusiasm they would name everything that interests them about the Universe that we live in and I would provide the information in a fun and interactive yet acceptable way for their level of understanding. In our class we learn about Earth and its place in the Solar System, we learn about the planets and other objects of our Solar System and about the Sun itself. We also explore the night sky using programs such as Stellarium, learning to recognize constellations and name them. Most of our activities are done using a PowerPoint presentation, YouTube videos, and Internet simulations followed by some practical work the students do themselves. Because of the lack of available materials and funds, most of materials are hand made by the teacher leading the class. We also use the school's galileoscope as often as possible. Every year the students are given the opportunity to go to an observatory in a town 90 km away so that they could gaze at the sky through the real telescope for the first time. Our goal is to start stepping into the world of astronomy by exploring the secrets of the Universe and understanding the process of rotation and revolution of our planet and its effects on our everyday lives and also to become more aware of our own role in our part of the Universe. The hunger for knowledge and enthusiasm these students have is contagious. They are becoming more aware of their surroundings and also understanding their place in the Universe that helps them remain humble and helps

  10. The New Amateur Astronomer

    Science.gov (United States)

    Mobberley, Martin

    Amateur astronomy has changed beyond recognition in less than two decades. The reason is, of course, technology. Affordable high-quality telescopes, computer-controlled 'go to' mountings, autoguiders, CCD cameras, video, and (as always) computers and the Internet, are just a few of the advances that have revolutionized astronomy for the twenty-first century. Martin Mobberley first looks at the basics before going into an in-depth study of what’s available commercially. He then moves on to the revolutionary possibilities that are open to amateurs, from imaging, through spectroscopy and photometry, to patrolling for near-earth objects - the search for comets and asteroids that may come close to, or even hit, the earth. The New Amateur Astronomer is a road map of the new astronomy, equally suitable for newcomers who want an introduction, or old hands who need to keep abreast of innovations. From the reviews: "This is one of several dozen books in Patrick Moore's "Practical Astronomy" series. Amid this large family, Mobberley finds his niche: the beginning high-tech amateur. The book's first half discusses equipment: computer-driven telescopes, CCD cameras, imaging processing software, etc. This market is changing every bit as rapidly as the computer world, so these details will be current for only a year or two. The rest of the book offers an overview of scientific projects that serious amateurs are carrying out these days. Throughout, basic formulas and technical terms are provided as needed, without formal derivations. An appendix with useful references and Web sites is also included. Readers will need more than this book if they are considering a plunge into high-tech amateur astronomy, but it certainly will whet their appetites. Mobberley's most valuable advice will save the book's owner many times its cover price: buy a quality telescope from a reputable dealer and install it in a simple shelter so it can be used with as little set-up time as possible. A poor

  11. The Very Large Array Data Processing Pipeline

    Science.gov (United States)

    Kent, Brian R.; Masters, Joseph S.; Chandler, Claire J.; Davis, Lindsey E.; Kern, Jeffrey S.; Ott, Juergen; Schinzel, Frank K.; Medlin, Drew; Muders, Dirk; Williams, Stewart; Geers, Vincent C.; Momjian, Emmanuel; Butler, Bryan J.; Nakazato, Takeshi; Sugimoto, Kanako

    2018-01-01

    We present the VLA Pipeline, software that is part of the larger pipeline processing framework used for the Karl G. Jansky Very Large Array (VLA), and Atacama Large Millimeter/sub-millimeter Array (ALMA) for both interferometric and single dish observations.Through a collection of base code jointly used by the VLA and ALMA, the pipeline builds a hierarchy of classes to execute individual atomic pipeline tasks within the Common Astronomy Software Applications (CASA) package. Each pipeline task contains heuristics designed by the team to actively decide the best processing path and execution parameters for calibration and imaging. The pipeline code is developed and written in Python and uses a "context" structure for tracking the heuristic decisions and processing results. The pipeline "weblog" acts as the user interface in verifying the quality assurance of each calibration and imaging stage. The majority of VLA scheduling blocks above 1 GHz are now processed with the standard continuum recipe of the pipeline and offer a calibrated measurement set as a basic data product to observatory users. In addition, the pipeline is used for processing data from the VLA Sky Survey (VLASS), a seven year community-driven endeavor started in September 2017 to survey the entire sky down to a declination of -40 degrees at S-band (2-4 GHz). This 5500 hour next-generation large radio survey will explore the time and spectral domains, relying on pipeline processing to generate calibrated measurement sets, polarimetry, and imaging data products that are available to the astronomical community with no proprietary period. Here we present an overview of the pipeline design philosophy, heuristics, and calibration and imaging results produced by the pipeline. Future development will include the testing of spectral line recipes, low signal-to-noise heuristics, and serving as a testing platform for science ready data products.The pipeline is developed as part of the CASA software package by an

  12. Astronomers Get New Tools for Gravitational-Wave Detection

    Science.gov (United States)

    2010-01-01

    Teamwork between gamma-ray and radio astronomers has produced a breakthrough in finding natural cosmic tools needed to make the first direct detections of the long-elusive gravitational waves predicted by Albert Einstein nearly a century ago. An orbiting gamma-ray telescope has pointed radio astronomers to specific locations in the sky where they can discover new millisecond pulsars. Millisecond pulsars, rapidly-spinning superdense neutron stars, can serve as extremely precise and stable natural clocks. Astronomers hope to detect gravitational waves by measuring tiny changes in the pulsars' rotation caused by the passage of the gravitational waves. To do this, they need a multitude of millisecond pulsars dispersed widely throughout the sky. However, nearly three decades after the discovery of the first millisecond pulsar, only about 150 of them had been found, some 90 of those clumped tightly in globular star clusters and thus unusable for detecting gravitational waves. The problem was that millisecond pulsars could only be discovered through arduous, computing-intensive searches of small portions of sky. "We've probably found far less than one percent of the millisecond pulsars in the Milky Way Galaxy," said Scott Ransom of the National Radio Astronomy Observatory (NRAO). The breakthrough came when an instrument aboard NASA's Fermi Gamma-Ray Space Telescope began surveying the sky in 2008. This instrument located hundreds of gamma-ray-emitting objects throughout our Galaxy, and astronomers suspected many of these could be millisecond pulsars. Paul Ray of the Naval Research Laboratory initiated an international collaboration to use radio telescopes to confirm the identity of these objects as millisecond pulsars. "The data from Fermi were like a buried-treasure map," Ransom said. "Using our radio telescopes to study the objects located by Fermi, we found 17 millisecond pulsars in three months. Large-scale searches had taken 10-15 years to find that many," Ransom

  13. Tools of radio astronomy

    CERN Document Server

    Wilson, Thomas L; Hüttemeister, Susanne

    2009-01-01

    The recent years have seen breathtaking progress in technology, especially in the receiver and digital technologies relevant for radio astronomy, which has at the same time advanced to shorter wavelengths. This is the updated and completely revised 5th edition of the most used introductory text in radio astronomy. It presents a unified treatment of the entire field from centimeter to sub-millimeter wavelengths. Topics covered include instruments, sensitivity considerations, observational methods and interpretations of the data recorded with both single dishes and interferometers. This text is useful to both students and experienced practicing astronomers. Besides making major updates and additions throughout the book, the authors have re-organized a number of chapters to more clearly separate basic theory from rapidly evolving practical aspects. Further, problem sets have been added at the end of each chapter.

  14. Radio Frequency Interference Site Survey for Thai Radio Telescopes

    Science.gov (United States)

    Jaroenjittichai, P.; Punyawarin, S.; Singwong, D.; Somboonpon, P.; Prasert, N.; Bandudej, K.; Kempet, P.; Leckngam, A.; Poshyachinda, S.; Soonthornthum, B.; Kramer, B.

    2017-09-01

    Radio astronomical observations have increasingly been threaten by the march of today telecommunication and wireless technology. Performance of radio telescopes lies within the fact that astronomical sources are extremely weak. National Astronomy Research Institute of Thailand (NARIT) has initiated a 5-year project, known as the Radio Astronomy Network and Geodesy for Development (RANGD), which includes the establishment of 40-meter and 13-meter radio telescopes. Possible locations have been narrowed down to three candidates, situated in the Northern part of Thailand, where the atmosphere is sufficiently dry and suitable for 22 and 43 GHz observations. The Radio Frequency Interference (RFI) measurements were carried out with a DC spectrum analyzer and directional antennas at 1.5 meter above ground, from 20 MHz to 6 GHz with full azimuth coverage. The data from a 3-minute pointing were recorded for both horizontal and vertical polarizations, in maxhold and average modes. The results, for which we used to make preliminary site selection, show signals from typical broadcast and telecommunication services and aeronautics applications. The signal intensity varies accordingly to the presence of nearby population and topography of the region.

  15. The Infrared Astronomical Satellite (IRAS) mission

    Science.gov (United States)

    Neugebauer, G.; Habing, H. J.; Van Duinen, R.; Aumann, H. H.; Beichman, C. A.; Baud, B.; Beintema, D. A.; Boggess, N.; Clegg, P. E.; De Jong, T.

    1984-01-01

    The Infrared Astronomical Satellite (IRAS) consists of a spacecraft and a liquid helium cryostat that contains a cooled IR telescope. The telescope's focal plane assembly is cooled to less than 3 K, and contains 62 IR detectors in the survey array which are arranged so that every source crossing the field of view can be seen by at least two detectors in each of four wavelength bands. The satellite was launched into a 900 km-altitude near-polar orbit, and its cryogenic helium supply was exhausted on November 22, 1983. By mission's end, 72 percent of the sky had been observed with three or more hours-confirming scans, and 95 percent with two or more hours-confirming scans. About 2000 stars detected at 12 and 25 microns early in the mission, and identified in the SAO (1966) catalog, have a positional uncertainty ellipse whose axes are 45 x 9 arcsec for an hours-confirmed source.

  16. Astronomers Gain Clues About Fundamental Physics

    Science.gov (United States)

    2005-12-01

    An international team of astronomers has looked at something very big -- a distant galaxy -- to study the behavior of things very small -- atoms and molecules -- to gain vital clues about the fundamental nature of our entire Universe. The team used the National Science Foundation's Robert C. Byrd Green Bank Telescope (GBT) to test whether the laws of nature have changed over vast spans of cosmic time. The Green Bank Telescope The Robert C. Byrd Green Bank Telescope CREDIT: NRAO/AUI/NSF (Click on image for GBT gallery) "The fundamental constants of physics are expected to remain fixed across space and time; that's why they're called constants! Now, however, new theoretical models for the basic structure of matter indicate that they may change. We're testing these predictions." said Nissim Kanekar, an astronomer at the National Radio Astronomy Observatory (NRAO), in Socorro, New Mexico. So far, the scientists' measurements show no change in the constants. "We've put the most stringent limits yet on some changes in these constants, but that's not the end of the story," said Christopher Carilli, another NRAO astronomer. "This is the exciting frontier where astronomy meets particle physics," Carilli explained. The research can help answer fundamental questions about whether the basic components of matter are tiny particles or tiny vibrating strings, how many dimensions the Universe has, and the nature of "dark energy." The astronomers were looking for changes in two quantities: the ratio of the masses of the electron and the proton, and a number physicists call the fine structure constant, a combination of the electron charge, the speed of light and the Planck constant. These values, considered fundamental physical constants, once were "taken as time independent, with values given once and forever" said German particle physicist Christof Wetterich. However, Wetterich explained, "the viewpoint of modern particle theory has changed in recent years," with ideas such as

  17. Choosing and using astronomical eyepieces

    CERN Document Server

    Paolini, William

    2013-01-01

    This valuable reference fills a number of needs in the field of astronomical eyepieces, including that of a buyer's guide, observer's field guide and technical desk reference. It documents the past market for eyepieces and its evolution right up to the present day. In addition to appealing to practical astronomers - and potentially saving them money - it is useful both as a historical reference and as a detailed review of the current market place for this bustling astronomical consumer product. What distinguishes this book from other publications on astronomy is the involvement of observers from all aspects of the astronomical community, and also the major manufacturers of equipment. It not only catalogs the technical aspects of the many modern eyepieces but also documents amateur observer reactions and impressions of their utility over the years, using many different eyepieces. Eyepieces are the most talked-about accessories and collectible items available to the amateur astronomer. No other item of equi...

  18. The Top Ten Astronomical 'breakthroughs' of the 20th century

    Directory of Open Access Journals (Sweden)

    Hughes, D. W.

    2007-10-01

    Full Text Available Astronomy was revolutionized in the 20th century. The electron was discovered in 1897 and this transformed spectroscopy and introduced plasma and magnetohydrodynamic physics and astro-chemistry. Einstein’s E = mc2, solved the problem of stellar energy generation and spawned the study of elemental nuclear synthesis. Large telescopes led to a boom in astronomical spectroscopic and photometric data collection, leading to such cornerstones as the Hertzprung-Russell diagram and the mass-luminosity relationship, and to the realization that the Universe contained a multitude of galaxies and was expanding. Radio astronomy was introduced and the advent of the space age saw the astronomical wavelength range expand into the ultraviolet, X-ray and gamma-ray regions, as well as the infrared and millimetre. We also startedwandering around roaming the Solar System instead of merely glimpsing its members from the bottom of our warm, turbulent atmosphere. Astronomical “breakthroughs” abounded. We have asked astronomers to select their “top ten” and these are listed and discussed in this paper.

  19. Astronomical Image and Data Analysis

    CERN Document Server

    Starck, J.-L

    2006-01-01

    With information and scale as central themes, this comprehensive survey explains how to handle real problems in astronomical data analysis using a modern arsenal of powerful techniques. It treats those innovative methods of image, signal, and data processing that are proving to be both effective and widely relevant. The authors are leaders in this rapidly developing field and draw upon decades of experience. They have been playing leading roles in international projects such as the Virtual Observatory and the Grid. The book addresses not only students and professional astronomers and astrophysicists, but also serious amateur astronomers and specialists in earth observation, medical imaging, and data mining. The coverage includes chapters or appendices on: detection and filtering; image compression; multichannel, multiscale, and catalog data analytical methods; wavelets transforms, Picard iteration, and software tools. This second edition of Starck and Murtagh's highly appreciated reference again deals with to...

  20. The Sardinia Radio Telescope . From a technological project to a radio observatory

    Science.gov (United States)

    Prandoni, I.; Murgia, M.; Tarchi, A.; Burgay, M.; Castangia, P.; Egron, E.; Govoni, F.; Pellizzoni, A.; Ricci, R.; Righini, S.; Bartolini, M.; Casu, S.; Corongiu, A.; Iacolina, M. N.; Melis, A.; Nasir, F. T.; Orlati, A.; Perrodin, D.; Poppi, S.; Trois, A.; Vacca, V.; Zanichelli, A.; Bachetti, M.; Buttu, M.; Comoretto, G.; Concu, R.; Fara, A.; Gaudiomonte, F.; Loi, F.; Migoni, C.; Orfei, A.; Pilia, M.; Bolli, P.; Carretti, E.; D'Amico, N.; Guidetti, D.; Loru, S.; Massi, F.; Pisanu, T.; Porceddu, I.; Ridolfi, A.; Serra, G.; Stanghellini, C.; Tiburzi, C.; Tingay, S.; Valente, G.

    2017-12-01

    Context. The Sardinia Radio Telescope (SRT) is the new 64 m dish operated by the Italian National Institute for Astrophysics (INAF). Its active surface, comprised of 1008 separate aluminium panels supported by electromechanical actuators, will allow us to observe at frequencies of up to 116 GHz. At the moment, three receivers, one per focal position, have been installed and tested: a 7-beam K-band receiver, a mono-feed C-band receiver, and a coaxial dual-feed L/P band receiver. The SRT was officially opened in September 2013, upon completion of its technical commissioning phase. In this paper, we provide an overview of the main science drivers for the SRT, describe the main outcomes from the scientific commissioning of the telescope, and discuss a set of observations demonstrating the scientific capabilities of the SRT. Aims: The scientific commissioning phase, carried out in the 2012-2015 period, proceeded in stages following the implementation and/or fine-tuning of advanced subsystems such as the active surface, the derotator, new releases of the acquisition software, etc. One of the main objectives of scientific commissioning was the identification of deficiencies in the instrumentation and/or in the telescope subsystems for further optimization. As a result, the overall telescope performance has been significantly improved. Methods: As part of the scientific commissioning activities, different observing modes were tested and validated, and the first astronomical observations were carried out to demonstrate the science capabilities of the SRT. In addition, we developed astronomer-oriented software tools to support future observers on site. In the following, we refer to the overall scientific commissioning and software development activities as astronomical validation. Results: The astronomical validation activities were prioritized based on technical readiness and scientific impact. The highest priority was to make the SRT available for joint observations as

  1. Choosing and using astronomical filters

    CERN Document Server

    Griffiths, Martin

    2014-01-01

    As a casual read through any of the major amateur astronomical magazines will demonstrate, there are filters available for all aspects of optical astronomy. This book provides a ready resource on the use of the following filters, among others, for observational astronomy or for imaging: Light pollution filters Planetary filters Solar filters Neutral density filters for Moon observation Deep-sky filters, for such objects as galaxies, nebulae and more Deep-sky objects can be imaged in much greater detail than was possible many years ago. Amateur astronomers can take

  2. The South African Astronomical Observatory

    International Nuclear Information System (INIS)

    1989-01-01

    The research work discussed in this report covers a wide range, from work on the nearest stars to studies of the distant quasars, and the astronomers who have carried out this work come from universities and observatories spread around the world as well as from South African universities and from the South African Astronomical Observatory (SAAO) staff itself. A characteristic of much of this work has been its collaborative character. SAAO studies in 1989 included: supernovae 1987A; galaxies; ground-based observations of celestial x-ray sources; the Magellanic Clouds; pulsating variables; galactic structure; binary star phenomena; the provision of photometric standards; nebulous matter; stellar astrophysics, and astrometry

  3. Unveiling galaxies the role of images in astronomical discovery

    CERN Document Server

    Roy, Jean-René

    2017-01-01

    Galaxies are known as the building blocks of the universe, but arriving at this understanding has been a thousand-year odyssey. This journey is told through the lens of the evolving use of images as investigative tools. Initial chapters explore how early insights developed in line with new methods of scientific imaging, particularly photography. The volume then explores the impact of optical, radio and x-ray imaging techniques. The final part of the story discusses the importance of atlases of galaxies; how astronomers organised images in ways that educated, promoted ideas and pushed for new knowledge. Images that created confusion as well as advanced knowledge are included to demonstrate the challenges faced by astronomers and the long road to understanding galaxies. By examining developments in imaging, this text places the study of galaxies in its broader historical context, contributing to both astronomy and the history of science.

  4. A FPGA-based Fast Converging Digital Adaptive Filter for Real-time RFI Mitigation on Ground Based Radio Telescopes

    Science.gov (United States)

    Finger, R.; Curotto, F.; Fuentes, R.; Duan, R.; Bronfman, L.; Li, D.

    2018-02-01

    Radio Frequency Interference (RFI) is a growing concern in the radio astronomy community. Single-dish telescopes are particularly susceptible to RFI. Several methods have been developed to cope with RF-polluted environments, based on flagging, excision, and real-time blanking, among others. All these methods produce some degree of data loss or require assumptions to be made on the astronomical signal. We report the development of a real-time, digital adaptive filter implemented on a Field Programmable Gate Array (FPGA) capable of processing 4096 spectral channels in a 1 GHz of instantaneous bandwidth. The filter is able to cancel a broad range of interference signals and quickly adapt to changes on the RFI source, minimizing the data loss without any assumption on the astronomical or interfering signal properties. The speed of convergence (for a decrease to a 1%) was measured to be 208.1 μs for a broadband noise-like RFI signal and 125.5 μs for a multiple-carrier RFI signal recorded at the FAST radio telescope.

  5. Tools of radio astronomy

    CERN Document Server

    Wilson, Thomas L; Hüttemeister, Susanne

    2013-01-01

    This 6th edition of “Tools of Radio Astronomy”, the most used introductory text in radio astronomy, has been revised to reflect the current state of this important branch of astronomy. This includes the use of satellites, low radio frequencies, the millimeter/sub-mm universe, the Cosmic Microwave Background and the increased importance of mm/sub-mm dust emission. Several derivations and presentations of technical aspects of radio astronomy and receivers, such as receiver noise, the Hertz dipole and  beam forming have been updated, expanded, re-worked or complemented by alternative derivations. These reflect advances in technology. The wider bandwidths of the Jansky-VLA and long wave arrays such as LOFAR and mm/sub-mm arrays such as ALMA required an expansion of the discussion of interferometers and aperture synthesis. Developments in data reduction algorithms have been included. As a result of the large amount of data collected in the past 20 years, the discussion of solar system radio astronomy, dust em...

  6. Performance evaluation of annular arrays in practice: The measurement of phase and amplitude patterns of radio-frequency deep body applicators

    NARCIS (Netherlands)

    Schneider, C.J.; Kuijer, J.P.A.; Colussi, L.C.; Schepp, C.J.; Dijk, J.D.P. van

    1995-01-01

    An approach to a solution of two major problems in operating Annular Phased Arrays in deep body hyperthermia is presented: an E-field sensor capable of measuring phase and amplitude at 70 MHz and the concept of a power transmission factor to determine the effective amplitude of each applicator. In

  7. The MARIACHI Project: Mixed Apparatus for Radio Investigation of Atmospheric Cosmic Rays of High Ionization

    Science.gov (United States)

    Inglis, M. D.; Takai, H.; Warasia, R.; Sundermier, J.

    2005-12-01

    Extreme Energy Cosmic Rays are nuclei that have been accelerated to kinetic energies in excess of 1020 eV. Where do they come from? How are they produced? Are they survivors of the early universe? Are they remnants of supernovas? MARIACHI, a unique collaboration between scientists, physics teachers and students, is an innovative technique that allows us to detect and study them. The Experiment MARIACHI is a unique research experiment that seeks the detection of extreme energy cosmic rays (EECRs), with E >1020 eV. It is an exciting project with many aspects: Research: It investigates an unconventional way of detecting EECRs based upon a method successfully used to detect meteors entering the upper atmosphere. The method was developed by planetary astronomers listening to radio signals reflected off the ionization trail. MARIACHI seeks to listen to TV signals reflected off the ionization trail of an EECR. The unique experiment topology will also permit the study of meteors, exotic forms of lightning, and atmospheric science. Computing and Technology: It uses radio detection stations, along with mini shower arrays hooked up to GPS clocks. Teachers and students build the arrays. It implements the Internet and the GRID as means of communication, data transfer, data processing, and for hosting a public educational outreach web site. Outreach and Education: It is an open research project with the active participation of a wide audience of astronomers, physicists, college professors, high school teachers and students. Groups representing high schools, community colleges and universities all collaborate in the project. The excitement of a real experiment motivates the science and technology classroom, and incorporates several high school physical science topics along with material from other disciplines such as astronomy, electronics, radio, optics.

  8. Astronomical Spectroscopy A Short History

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 3; Issue 5. Astronomical Spectroscopy A Short History. J C Bhattacharyya. General Article Volume 3 Issue 5 May 1998 pp 24-29. Fulltext. Click here to view fulltext PDF. Permanent link: https://www.ias.ac.in/article/fulltext/reso/003/05/0024-0029 ...

  9. A refined astronomically calibrated 40Ar/39Ar age for Fish Canyon sanidine

    NARCIS (Netherlands)

    Rivera, T.A.; Storey, M.; Zeeden, C.; Hilgen, F.J.; Kuiper, K.

    2011-01-01

    Intercalibration between the astronomical and radio-isotopic dating methods provides a means to improving accuracy and reducing uncertainty of an integrated, multi-chronometer geologic timescale. Here we report a high-precision 40Ar/39Ar age for the FishCanyon sanidine (FCs) neutron fluence monitor,

  10. Radio Frequency Interference: The Study of Rain Effect on Radio Signal Attenuation

    International Nuclear Information System (INIS)

    Roslan Umar; Roslan Umar; Shahirah Syafa Sulan; Atiq Wahidah Azlan; Zainol Abidin Ibrahim

    2015-01-01

    The intensity of radio waves received by radio telescopes is always not subject to human control. In the millimetre band, the propagation of the electromagnetic waves is severely affected by rain rate, dust particle size and drop size in the terms of attenuation, noise and depolarization. At the frequency above 10 GHz, the absorption and scattering by rain cause a reduction in the transmitted signal amplitude which will lead to the reducing of the availability, reliability and performance on the communications link. In this study, the rain effect on radio signal has been investigated. Spectrum analyzer and weather stations were used to obtain the RFI level and rain rate data respectively. The radio frequency interference (RFI) pattern due to rain factor was determined. This will benefit radio astronomer in managing sites for radio observation for radio astronomy purposes. (author)

  11. Radio stars

    International Nuclear Information System (INIS)

    Hjellming, R.M.

    1976-01-01

    Any discussion of the radio emission from stars should begin by emphasizing certain unique problems. First of all, one must clarify a semantic confusion introduced into radio astronomy in the late 1950's when most new radio sources were described as radio stars. All of these early 'radio stars' were eventually identified with other galactic and extra-galactic objects. The study of true radio stars, where the radio emission is produced in the atmosphere of a star, began only in the 1960's. Most of the work on the subject has, in fact, been carried out in only the last few years. Because the real information about radio stars is quite new, it is not surprising that major aspects of the subject are not at all understood. For this reason this paper is organized mainly around three questions: what is the available observational information; what physical processes seem to be involved; and what working hypotheses look potentially fruitful. (Auth.)

  12. Latin American astronomers and the International Astronomical Union

    Science.gov (United States)

    Torres-Peimbert, S.

    2017-07-01

    Selected aspects of the participation of the Latin American astronomers in the International Astronomical Union are presented: Membership, Governing bodies, IAU meetings, and other activities. The Union was founded in 1919 with 7 initial member states, soon to be followed by Brazil. In 1921 Mexico joined, and in 1928 Argentina also formed part of the Union, while Chile joined in 1947. In 1961 Argentina, Brazil, Chile, Mexico and Venezuela were already member countries. At present (October 2016) 72 countries contribute financially to the Union. The Union lists 12,391 professional astronomers as individual members; of those, 692 astronomers work in Latin America and the Caribbean, from 13 member states (Argentina, Bolivia , Brazil, Chile, Colombia, Costa Rica, Cuba, Honduras, Mexico, Panamá, Perú, Uruguay and Venezuela) as well as from Ecuador and Puerto Rico. This group comprises 5.58% of the total membership, a figure somewhat lower than the fraction of the population in the region, which is 8.6% of the world population. Of the Latin American members, 23.4% are women and 76.6% are men; slightly higher than the whole membership of Union, which is of 16.9%. In the governing bodies it can be mentioned that there have been 2 Presidents of the Union (Jorge Sahade and Silvia Torres-Peimbert), 7 VicePresidents (Guillermo Haro, Jorge Sahade, Manuel Peimbert Claudio Anguita, Silvia Torres-Peimbert, Beatriz Barbuy, and Marta G. Rovira). The IAU meetings held in the region, include 2 General Assemblies (the 1991 XXI GA took place in Buenos Aires, Argentina and the 2009 XXVIII GA, in Rio de Janeiro, Brazil), 15 Regional Meetings (in Argentina, Brazil, Chile, Colombia, Mexico, Venezuela and Uruguay), 29 Symposia (in Argentina, Brazil, Chile, Colombia, Costa Rica, Ecuador, Peru and Mexico), 5 Colloquia (in Argentina and Mexico), 8 International Schools for Young Astronomers (in Argentina, Brazil, Cuba, Honduras and Mexico), and 11 projects sponsored by the Office of Astronomy

  13. The astronomical tables of Giovanni Bianchini

    CERN Document Server

    Chabas, Jose

    2009-01-01

    This book describes and analyses, for the first time, the astronomical tables of Giovanni Bianchini of Ferrara (d. after 1469), explains their context, inserts them into an astronomical tradition that began in Toledo, and addresses their diffusion.

  14. Aperture synthesis observations of solar and stellar radio emission

    International Nuclear Information System (INIS)

    Bastian, T.S.

    1987-01-01

    The work presented in this thesis relied upon the radio astronomical instrument, The Very Large Array. The thesis is divided into three major sections. In the first the author applied maximum entropy-type image reconstruction techniques, using both single dish and iterferometer data, to generate full disk images of the Sun at a wavelength λ ∼ 21 cm. Using a set of six such images obtained during the Sun's decline from sunspot maximum to minimum, he has noted a number of previously unreported phenomena. Among these: (1) a systematic decrease in quiet Sun's brightness temperature as it declined to minimum; (2) a systematic decrease in the Sun's radius at 21 cm; (3) evidence for the evolution of polar coronal holes during the course of the solar cycle. The observed variation, though not noted previously at radio wavelengths, is entirely consistent with white light K coronagraph data. The results reported here explain the conflicting nature of a number of past observations. In the second section of the thesis, he presents the results of a long term survey of magnetic cataclysmic variables (CVs). Cataclysmic variables are close binary systems which contain a white dwarf accreting mass from a late-type secondary, typically a dwarf of spectral type, G, K, or M. The survey resulted in the detection of two out of the eighteen systems observed. In the third section of the thesis, he presents new results on flare stars in the solar neighborhood and in the Pleiades. He has successfully employed the technique of dynamic spectroscopy to constrain the mechanisms(s) for radio flaring on other stars. The second part of section three is devoted to a search for radio emission from flare stars in the Pleiades which was motivated by the evolutionary questions raised by flare stars and the Pleiades lower main sequence

  15. Astronomical Heritage in the National Culture

    Science.gov (United States)

    Harutyunian, H. A.; Mickaelian, A. M.; Parsamian, E. S.

    2014-10-01

    The book contains Proceedings of the Archaeoastronomical Meeting "Astronomical Heritage in the National Culture" Dedicated to Anania Shirakatsi's 1400th Anniversary and XI Annual Meeting of the Armenian Astronomical Society. It consists of 3 main sections: "Astronomical Heritage", "Anania Shirakatsi" and "Modern Astronomy", as well as Literature about Anania Shirakatsi is included. The book may be interesting for astronomers, historians, archaeologists, linguists, students and other readers.

  16. Characterizing Interference in Radio Astronomy Observations through Active and Unsupervised Learning

    Science.gov (United States)

    Doran, G.

    2013-01-01

    In the process of observing signals from astronomical sources, radio astronomers must mitigate the effects of manmade radio sources such as cell phones, satellites, aircraft, and observatory equipment. Radio frequency interference (RFI) often occurs as short bursts (active learning approach in which an astronomer labels events that are most confusing to a classifier, minimizing the human effort required for classification. We also explore the use of unsupervised clustering techniques, which automatically group events into classes without user input. We apply these techniques to data from the Parkes Multibeam Pulsar Survey to characterize several million detected RFI events from over a thousand hours of observation.

  17. Development of Very Long Baseline Interferometry (VLBI) techniques in New Zealand: Array simulation, image synthesis and analysis

    Science.gov (United States)

    Weston, S. D.

    2008-04-01

    This thesis presents the design and development of a process to model Very Long Base Line Interferometry (VLBI) aperture synthesis antenna arrays. In line with the Auckland University of Technology (AUT) Institute for Radiophysics and Space Research (IRSR) aims to develop the knowledge, skills and experience within New Zealand, extensive use of existing radio astronomical software has been incorporated into the process namely AIPS (Astronomical Imaging Processing System), MIRIAD (a radio interferometry data reduction package) and DIFMAP (a program for synthesis imaging of visibility data from interferometer arrays of radio telescopes). This process has been used to model various antenna array configurations for two proposed New Zealand sites for antenna in a VLBI array configuration with existing Australian facilities and a passable antenna at Scott Base in Antarctica; and the results are presented in an attempt to demonstrate the improvement to be gained by joint trans-Tasman VLBI observation. It is hoped these results and process will assist the planning and placement of proposed New Zealand radio telescopes for cooperation with groups such as the Australian Long Baseline Array (LBA), others in the Pacific Rim and possibly globally; also potential future involvement of New Zealand with the SKA. The developed process has also been used to model a phased building schedule for the SKA in Australia and the addition of two antennas in New Zealand. This has been presented to the wider astronomical community via the Royal Astronomical Society of New Zealand Journal, and is summarized in this thesis with some additional material. A new measure of quality ("figure of merit") for comparing the original model image and final CLEAN images by utilizing normalized 2-D cross correlation is evaluated as an alternative to the existing subjective visual operator image comparison undertaken to date by other groups. This new unit of measure is then used ! in the presentation of the

  18. Astronomers Discover Fastest-Spinning Pulsar

    Science.gov (United States)

    2006-01-01

    Astronomers using the National Science Foundation's Robert C. Byrd Green Bank Telescope have discovered the fastest-spinning neutron star ever found, a 20-mile-diameter superdense pulsar whirling faster than the blades of a kitchen blender. Their work yields important new information about the nature of one of the most exotic forms of matter known in the Universe. Pulsar Graphic Pulsars Are Spinning Neutron Stars CREDIT: Bill Saxton, NRAO/AUI/NSF (Click on image for larger version) "We believe that the matter in neutron stars is denser than an atomic nucleus, but it is unclear by how much. Our observations of such a rapidly rotating star set a hard upper limit on its size, and hence on how dense the star can be.," said Jason Hessels, a graduate student at McGill University in Montreal. Hessels and his colleagues presented their findings to the American Astronomical Society's meeting in Washington, DC. Pulsars are spinning neutron stars that sling "lighthouse beams" of radio waves or light around as they spin. A neutron star is what is left after a massive star explodes at the end of its "normal" life. With no nuclear fuel left to produce energy to offset the stellar remnant's weight, its material is compressed to extreme densities. The pressure squeezes together most of its protons and electrons to form neutrons; hence, the name "neutron star." "Neutron stars are incredible laboratories for learning about the physics of the fundamental particles of nature, and this pulsar has given us an important new limit," explained Scott Ransom, an astronomer at the National Radio Astronomy Observatory and one of Hessels' collaborators on this work. The scientists discovered the pulsar, named PSR J1748-2446ad, in a globular cluster of stars called Terzan 5, located some 28,000 light-years from Earth in the constellation Sagittarius. The newly-discovered pulsar is spinning 716 times per second, or at 716 Hertz (Hz), readily beating the previous record of 642 Hz from a pulsar

  19. Wide Field Radio Transient Surveys

    Science.gov (United States)

    Bower, Geoffrey

    2011-04-01

    The time domain of the radio wavelength sky has been only sparsely explored. Nevertheless, serendipitous discovery and results from limited surveys indicate that there is much to be found on timescales from nanoseconds to years and at wavelengths from meters to millimeters. These observations have revealed unexpected phenomena such as rotating radio transients and coherent pulses from brown dwarfs. Additionally, archival studies have revealed an unknown class of radio transients without radio, optical, or high-energy hosts. The new generation of centimeter-wave radio telescopes such as the Allen Telescope Array (ATA) will exploit wide fields of view and flexible digital signal processing to systematically explore radio transient parameter space, as well as lay the scientific and technical foundation for the Square Kilometer Array. Known unknowns that will be the target of future transient surveys include orphan gamma-ray burst afterglows, radio supernovae, tidally-disrupted stars, flare stars, and magnetars. While probing the variable sky, these surveys will also provide unprecedented information on the static radio sky. I will present results from three large ATA surveys (the Fly's Eye survey, the ATA Twenty CM Survey (ATATS), and the Pi GHz Survey (PiGSS)) and several small ATA transient searches. Finally, I will discuss the landscape and opportunities for future instruments at centimeter wavelengths.

  20. The Effect of Solar Radiation on Radio Signal for Radio Astronomy Purposes

    International Nuclear Information System (INIS)

    Nor Hazmin Sabri; Atiq Wahidah Azlan; Roslan Umar; Roslan Umar; Shahirah Syafa Sulan; Zainol Abidin Ibrahim; Wan Zul Adli Wan Mokhtar

    2015-01-01

    Radio astronomy is a subfields of astronomy which is discovers the celestial objects at radio frequencies. Observation in radio astronomy is conducted using single antenna or array of antennas, known as radio telescope. Other than that, radio astronomy also holds an advantage over other alternatives to optical astronomy due to its capability of observing from the ground level. In this study, the effect of solar radiation that contributes the Radio Frequency Interferences (RFI) is reviewed. The low RFI level is required to set up the radio telescope for radio astronomy observation. The effect of solar radiation on radio signal was investigated by determining the RFI pattern using spectrum analyzer. The solar radiation data was obtained from weather station located at KUSZA Observatory, East Coast Environmental Research Institute (ESERI), UniSZA. We can conclude that the solar radiation factor give the minimum significant effect to radio signal. (author)

  1. 125th Colloquium of the International Astronomical Union

    CERN Document Server

    Sorochenko, R

    1990-01-01

    Text no 1 Radio Recombination Lines (RRLs), discovered in the USSR in 1964, have become a powerful research tool for astronomers. Available throughout the radio spectrum, these lines carry information regarding the density, temperature, turbulence and velocity of thermal plasmas. Their very existance shows the presence of thermal gas. They also can carry information regarding magnetic fields if Zeeman splitting were to be detected. Containing the proceedings of an IAU Colloquium celebrating the 25th anniversary of their detection, this volume tells us what has happened since. It contains the story of the detection of RRLs and reviews of many areas of physics of the interstellargas from which stars form, HII regions excited by newly formed stars, planetary nebulae involving dying stars, and the structure of our Milky Way and other galaxies reflecting the large-scale morphology of the star formation process. In addition there is an article describing modern laboratory studies of Rydberg atoms to probe the basic...

  2. Super resolution for astronomical observations

    Science.gov (United States)

    Li, Zhan; Peng, Qingyu; Bhanu, Bir; Zhang, Qingfeng; He, Haifeng

    2018-05-01

    In order to obtain detailed information from multiple telescope observations a general blind super-resolution (SR) reconstruction approach for astronomical images is proposed in this paper. A pixel-reliability-based SR reconstruction algorithm is described and implemented, where the developed process incorporates flat field correction, automatic star searching and centering, iterative star matching, and sub-pixel image registration. Images captured by the 1-m telescope at Yunnan Observatory are used to test the proposed technique. The results of these experiments indicate that, following SR reconstruction, faint stars are more distinct, bright stars have sharper profiles, and the backgrounds have higher details; thus these results benefit from the high-precision star centering and image registration provided by the developed method. Application of the proposed approach not only provides more opportunities for new discoveries from astronomical image sequences, but will also contribute to enhancing the capabilities of most spatial or ground-based telescopes.

  3. National Astronomical Observatory of Japan

    CERN Document Server

    Haubold, Hans J; UN/ESA/NASA Workshop on the International Heliophysical Year 2007 and Basic Space Science, hosted by the National Astronomical Observatory of Japan

    2010-01-01

    This book represents Volume II of the Proceedings of the UN/ESA/NASA Workshop on the International Heliophysical Year 2007 and Basic Space Science, hosted by the National Astronomical Observatory of Japan, Tokyo, 18 - 22 June, 2007. It covers two programme topics explored in this and past workshops of this nature: (i) non-extensive statistical mechanics as applicable to astrophysics, addressing q-distribution, fractional reaction and diffusion, and the reaction coefficient, as well as the Mittag-Leffler function and (ii) the TRIPOD concept, developed for astronomical telescope facilities. The companion publication, Volume I of the proceedings of this workshop, is a special issue in the journal Earth, Moon, and Planets, Volume 104, Numbers 1-4, April 2009.

  4. Astronomical Data and Information Visualization

    Science.gov (United States)

    Goodman, Alyssa A.

    2010-01-01

    As the size and complexity of data sets increases, the need to "see" them more clearly increases as well. In the past, many scientists saw "fancy" data and information visualization as necessary for "outreach," but not for research. In this talk, I wlll demonstrate, using specific examples, why more and more scientists--not just astronomers--are coming to rely upon the development of new visualization strategies not just to present their data, but to understand it. Principal examples will be drawn from the "Astronomical Medicine" project at Harvard's Initiative in Innovative Computing, and from the "Seamless Astronomy" effort, which is co-sponsored by the VAO (NASA/NSF) and Microsoft Research.

  5. Astronomical optics and elasticity theory

    CERN Document Server

    Lemaitre, Gerard Rene

    2008-01-01

    Astronomical Optics and Elasticity Theory provides a very thorough and comprehensive account of what is known in this field. After an extensive introduction to optics and elasticity, the book discusses variable curvature and multimode deformable mirrors, as well as, in depth, active optics, its theory and applications. Further, optical design utilizing the Schmidt concept and various types of Schmidt correctors, as well as the elasticity theory of thin plates and shells are elaborated upon. Several active optics methods are developed for obtaining aberration corrected diffraction gratings. Further, a weakly conical shell theory of elasticity is elaborated for the aspherization of grazing incidence telescope mirrors. The very didactic and fairly easy-to-read presentation of the topic will enable PhD students and young researchers to actively participate in challenging astronomical optics and instrumentation projects.

  6. Astronomical Research Institute Photometric Results

    Science.gov (United States)

    Linder, Tyler R.; Sampson, Ryan; Holmes, Robert

    2013-01-01

    The Astronomical Research Institute (ARI) conducts astrometric and photometric studies of asteroids with a concentration on near-Earth objects (NEOs). A 0.76-m autoscope was used for photometric studies of seven asteroids of which two were main-belt targets and five were NEOs, including one potentially hazardous asteroid (PHA). These objects are: 3122 Florence, 3960 Chaliubieju, 5143 Heracles, (6455) 1992 HE, (36284) 2000 DM8, (62128) 2000 SO1, and 2010 LF86.

  7. The South African Astronomical Observatory

    International Nuclear Information System (INIS)

    1988-01-01

    The geographical position, climate and equipment at the South African Astronomical Observatory (SAAO), together with the enthusiasm and efforts of SAAO scientific and technical staff and of visiting scientists, have enabled the Observatory to make a major contribution to the fields of astrophysics and cosmology. During 1987 the SAAO has been involved in studies of the following: supernovae; galaxies, including Seyfert galaxies; celestial x-ray sources; magellanic clouds; pulsating variables; galatic structure; binary star phenomena; nebulae; interstellar matter and stellar astrophysics

  8. Astronomical publications of Melbourne Observatory

    Science.gov (United States)

    Andropoulos, Jenny Ioanna

    2014-05-01

    During the second half of the 19th century and the first half of the 20th century, four well-equipped government observatories were maintained in Australia - in Melbourne, Sydney, Adelaide and Perth. These institutions conducted astronomical observations, often in the course of providing a local time service, and they also collected and collated meteorological data. As well, some of these observatories were involved at times in geodetic surveying, geomagnetic recording, gravity measurements, seismology, tide recording and physical standards, so the term "observatory" was being used in a rather broad sense! Despite the international renown that once applied to Williamstown and Melbourne Observatories, relatively little has been written by modern-day scholars about astronomical activities at these observatories. This research is intended to rectify this situation to some extent by gathering, cataloguing and analysing the published astronomical output of the two Observatories to see what contributions they made to science and society. It also compares their contributions with those of Sydney, Adelaide and Perth Observatories. Overall, Williamstown and Melbourne Observatories produced a prodigious amount of material on astronomy in scientific and technical journals, in reports and in newspapers. The other observatories more or less did likewise, so no observatory of those studied markedly outperformed the others in the long term, especially when account is taken of their relative resourcing in staff and equipment.

  9. ISO Results Presented at International Astronomical Union

    Science.gov (United States)

    1997-08-01

    this study of Cassiopeia A. "With ISO's camera we can pick out emissions from various elements, and we find that clumps of hot material flung out from the star evolve directly into corresponding clumps of dust." In contrast the Trifid Nebula is region of rebirth, where massive stars of a new generation are forming. Seen by visible light, hot young stars light up a large cloud of gas. It is criss-crossed by dark dust clouds which divide the bright nebula and give it its name. An infrared image from ISO shows a remarkable change in appearance. The dark clouds become luminous and the bright regions are dark. By its trick of penetrating the dust, ISO reveals dense regions inside the obscuring clouds, where new stars are forming. The cosmic egg from which a star will hatch One prize sought by ISO astronomers has been the detection of the earliest stages of star formation. Pre-stellar cores are egg-like objects hidden within a larger dust cloud. A cold, thick shell of dust obscures the interior, where gas collapses under gravity to make an embryonic star. By the time the dust has dispersed, and the object inside has hatched as a plainly visible star, the main event of star formation is complete. In the earliest stages, only radio waves and far-infrared rays can escape from the dust cloud, allowing us to observe the real origins of the stars. Derek Ward-Thompson of the Royal Observatory Edinburgh (UK) and his colleagues at Cambridge University and in France, first detected the pre-stellar core L1689B, using observations at sub-millimetre radio wavelengths, in the constellation Ophiuchus. It is a very young pre-stellar core, on the brink of collapsing to form a new star. Now the team has used ISO to make the first infrared images of L1689B using the photometer ISOPHOT at long infrared wavelengths, up to its limit of 200 microns. The shell of dust is so cold, at roughly minus 260 degrees Centigrade (or 13 K), it is undetectable even at short or medium infrared wavelengths

  10. Automated solar radio burst detection on radio spectrum: a review of ...

    African Journals Online (AJOL)

    By doing manual detection, human effort and error become the issues when the solar astronomer needs the fast and accurate result. Recently, the success of various techniques in image processing to identify solar radio burst automatically was presented. This paper reviews previous technique in image processing.

  11. Synthesis imaging in radio astronomy

    International Nuclear Information System (INIS)

    Perley, R.A.; Schwab, F.R.; Bridle, A.H.

    1989-01-01

    Recent advances in techniques and instrumentation for radio synthesis imaging in astronomy are discussed in a collection of review essays. Topics addressed include coherence in radio astronomy, the interferometer in practice, primary antenna elements, cross correlators, calibration and editing, sensitivity, deconvolution, self-calibration, error recognition, and image analysis. Consideration is given to wide-field imaging (bandwidth and time-average smearing, noncoplanar arrays, and mosaicking), high-dynamic-range imaging, spectral-line imaging, VLBI, solar imaging with a synthesis telescope, synthesis imaging of spatially coherent objects, noise in images of very bright sources, synthesis observing strategies, and the design of aperture-synthesis arrays

  12. CHANG-ES. IV. RADIO CONTINUUM EMISSION OF 35 EDGE-ON GALAXIES OBSERVED WITH THE KARL G. JANSKY VERY LARGE ARRAY IN D CONFIGURATION—DATA RELEASE 1

    Energy Technology Data Exchange (ETDEWEB)

    Wiegert, Theresa; Irwin, Judith; MacGregor, Stephen, E-mail: twiegert@astro.queensu.ca, E-mail: irwin@astro.queensu.ca, E-mail: 11sm36@queensu.ca [Department of Physics, Engineering Physics, and Astronomy, Queen' s University, Kingston, ON, K7L 3N6 (Canada); and others

    2015-09-15

    We present the first part of the observations made for the Continuum Halos in Nearby Galaxies, an EVLA Survey (CHANG-ES) project. The aim of the CHANG-ES project is to study and characterize the nature of radio halos, their prevalence as well as their magnetic fields, and the cosmic rays illuminating these fields. This paper reports observations with the compact D configuration of the Karl G. Jansky Very Large Array (VLA) for the sample of 35 nearby edge-on galaxies of CHANG-ES. With the new wide bandwidth capabilities of the VLA, an unprecedented sensitivity was achieved for all polarization products. The beam resolution is an average of 9.″6 and 36″ with noise levels reaching approximately 6 and 30 μJy beam{sup −1} for C- and L-bands, respectively (robust weighting). We present intensity maps in these two frequency bands (C and L), with different weightings, as well as spectral index maps, polarization maps, and new measurements of star formation rates (SFRs). The data products described herein are available to the public in the CHANG-ES data release available at http://www.queensu.ca/changes. We also present evidence of a trend among galaxies with larger halos having higher SFR surface density, and we show, for the first time, a radio continuum image of the median galaxy, taking advantage of the collective signal-to-noise ratio of 30 of our galaxies. This image shows clearly that a “typical” spiral galaxy is surrounded by a halo of magnetic fields and cosmic rays.

  13. New Mexico Fiber-Optic Link Marks Giant Leap Toward Future of Radio Astronomy

    Science.gov (United States)

    1998-12-01

    SOCORRO, NM -- Scientists and engineers at the National Radio Astronomy Observatory (NRAO) have made a giant leap toward the future of radio astronomy by successfully utilizing the Very Large Array (VLA) radio telescope in conjunction with an antenna of the continent-wide Very Long Baseline Array (VLBA) using the longest fiber-optic data link ever demonstrated in radio astronomy. The 65-mile fiber link will allow scientists to use the two National Science Foundation (NSF) facilities together in real time, and is the first step toward expanding the VLA to include eight proposed new radio-telescope antennas throughout New Mexico. LEFT: Miller Goss, NRAO's director of VLA/VLBA Operations, unveils graphic showing success of the Pie Town-VLA fiber link. The project, funded by the NSF and Associated Universities, Inc. (AUI), which operates NRAO for the NSF, links the VLA and the VLBA antenna in Pie Town, NM, using a Western New Mexico Telephone Co. fiber-optic cable. The successful hookup was announced at a ceremony that also marked the 10th anniversary of NRAO's Operations Center in Socorro. "Linking the Pie Town antenna to the VLA quadruples the VLA's ability to make detailed images of astronomical objects," said Paul Vanden Bout, NRAO's Director. "This alone makes the link an advance for science, but its greater importance is that it clearly demonstrates the technology for improving the VLA's capabilities even more in the future." "Clearly, the big skies and wide open spaces in New Mexico create near perfect conditions for the incredible astronomical assets located in our state. This new fiber-optic link paves the way for multiplying the already breathtaking scientific capabilities of the VLA," Senator Pete Domenici (R-NM) said. The VLA is a system of 27 radio-telescope antennas distributed over the high desert west of Socorro, NM, in the shape of a giant "Y." Made famous in movies, commercials and numerous published photos, the VLA has been one of the most productive

  14. Development of superconducting tunnel junction arrays for astronomical observations

    NARCIS (Netherlands)

    Martin, D.

    2007-01-01

    The original S-CAM1 and 2 systems were a first successful demonstration of a camera for optical astronomy based on superconducting sensors. However, a number of shortcomings were identified during the observing campaigns at the William Herschel Telescope at La Palma that triggered this work. As the

  15. Hexabundles: imaging fibre arrays for low-light astronomical applications

    DEFF Research Database (Denmark)

    Bland-Hawthorn, Joss; Bryant, Julie; Robertson, Gordon

    2010-01-01

    We demonstrate for the first time an imaging fibre bundle (“hexabundle”) that is suitable for low-light applications in astronomy. The most successful survey instruments at optical-infrared wavelengths today have obtained data on up to a million celestial sources using hundreds of multimode fibre...

  16. "Special Case" Stellar Blast Teaching Astronomers New Lessons About Cosmic Explosions

    Science.gov (United States)

    2006-07-01

    A powerful thermonuclear explosion on a dense white-dwarf star last February has given astronomers their best look yet at the early stages of such explosions, called novae, and also is giving them tantalizing new clues about the workings of bigger explosions, called supernovae, that are used to measure the Universe. RS Ophiuchi Expansion RS Ophiuchi Expansion CREDIT: Rupen, Mioduszewski & Sokoloski, NRAO/AUI/NSF (Click on image for full-sized image and detailed caption) Using the National Science Foundation's Very Long Baseline Array (VLBA) and other telescopes, "We have seen structure in the blast earlier than in any other stellar explosion," said Tim O'Brien of the University of Manchester's Jodrell Bank Observatory in the U.K. "We see evidence that the explosion may be ejecting material in jets, contrary to theoretical models that assumed a spherical shell of ejected material," O'Brien added. The explosion occurred in a star system called RS Ophiuchi, in the constellation Ophiuchus. RS Ophiuchi consists of a dense white dwarf star with a red giant companion whose prolific stellar wind dumps material onto the surface of the white dwarf. When enough of this material has accumulated, theorists say, a gigantic thermonuclear explosion, similar to a hydrogen bomb but much larger, occurs. Systems such as RS Ophiuchi may eventually produce a vastly more powerful explosion -- a supernova -- when the white dwarf accumulates enough mass to cause it to collapse and explode violently. Because such supernova explosions (called Type 1a supernovae by astronomers) all are triggered as the white dwarf reaches the same mass, they are thought to be identical in their intrinsic brightness. This makes them extremely valuable as "standard candles" for measuring distances in the Universe. "We think the white dwarf in RS Ophiuchi is about as massive as a white dwarf can get, and so is close to the point when it will become a supernova," said Jennifer Sokoloski, of the Harvard

  17. Visualizing Astronomical Data with Blender

    Science.gov (United States)

    Kent, Brian R.

    2014-01-01

    We present methods for using the 3D graphics program Blender in the visualization of astronomical data. The software's forte for animating 3D data lends itself well to use in astronomy. The Blender graphical user interface and Python scripting capabilities can be utilized in the generation of models for data cubes, catalogs, simulations, and surface maps. We review methods for data import, 2D and 3D voxel texture applications, animations, camera movement, and composite renders. Rendering times can be improved by using graphic processing units (GPUs). A number of examples are shown using the software features most applicable to various kinds of data paradigms in astronomy.

  18. Focus on astronomical predictable events

    DEFF Research Database (Denmark)

    Jacobsen, Aase Roland

    2006-01-01

    At the Steno Museum Planetarium we have for many occasions used a countdown clock to get focus om astronomical events. A countdown clock can provide actuality to predictable events, for example The Venus Transit, Opportunity landing on Mars and The Solar Eclipse. The movement of the clock attracs...... the public and makes a point of interest in a small exhibit area. A countdown clock can be simple, but it is possible to expand the concept to an eye-catching part of a museum....

  19. Strasbourg Astronomical Data Center (CDS

    Directory of Open Access Journals (Sweden)

    F Genova

    2013-01-01

    Full Text Available The Centre de Donnees astronomiques de Strasbourg (CDS, created in 1972, has been a pioneer in the dissemination of digital scientific data. Ensuring sustainability for several decades has been a major issue because science and technology evolve continuously and the data flow increases endlessly. The paper briefly describes CDS activities, major services, and its R&D strategy to take advantage of new technologies. The next frontiers for CDS are the new Web 2.0/3.0 paradigm and, at a more general level, global interoperability of astronomical on-line resources in the Virtual Observatory framework.

  20. astroplan: Observation Planning for Astronomers

    Science.gov (United States)

    Morris, Brett

    2016-03-01

    Astroplan is an observation planning package for astronomers. It is an astropy-affiliated package which began as a Google Summer of Code project. Astroplan facilitates convenient calculation of common observational quantities, like target altitudes and azimuths, airmasses, and rise/set times. Astroplan also computes when targets are observable given various extensible observing constraints, for example: within a range of airmasses or altitudes, or at a given separation from the Moon. Astroplan is taught in the undergraduate programming for astronomy class, and enables observational Pre- MAP projects at the University of Washington. In the near future, we plan to implement scheduling capabilities in astroplan on top of the constraints framework.

  1. Explanatory supplement to the astronomical almanac

    CERN Document Server

    Urban, Sean E

    2013-01-01

    The Explanatory Supplement to the Astronomical Almanac offers explanatory material, supplemental information and detailed descriptions of the computational models and algorithms used to produce The Astronomical Almanac, which is an annual publication prepared jointly by the US Naval Observatory and Her Majesty's Nautical Almanac Office in the UK. Like The Astronomical Almanac, The Explanatory Supplement provides detailed coverage of modern positional astronomy. Chapters are devoted to the celestial and terrestrial reference frames, orbital ephemerides, precession, nutation, Earth rotation, and coordinate transformations. These topics have undergone substantial revisions since the last edition was published. Astronomical positions are intertwined with timescales and relativity in The Astronomical Almanac, so related chapters are provided in The Explanatory Supplement. The Astronomical Almanac also includes information on lunar and solar eclipses, physical ephemerides of solar system bodies, and calendars, so T...

  2. Radio Telescopes' Precise Measurements Yield Rich Scientific Payoffs

    Science.gov (United States)

    2008-01-01

    Having the sharpest pictures always is a big advantage, and a sophisticated radio-astronomy technique using continent-wide and even intercontinental arrays of telescopes is yielding extremely valuable scientific results in a wide range of specialties. That's the message delivered to the American Astronomical Society's meeting in Austin, Texas, by Mark Reid of the Harvard-Smithsonian Center for Astrophysics, a leading researcher in the field of ultra-precise astronomical position measurements. Very Long Baseline Interferometry provides extremely high precision that can extend use of the parallax technique to many more celestial objects. Parallax is a direct means of measuring cosmic distances by detecting the slight shift in an object’s apparent position in the sky caused by Earth’s orbital motion. Credit: Bill Saxton, NRAO/AUI/NSF "Using radio telescopes, we are measuring distances and motions of celestial bodies with unprecedented accuracy. That's helping us better understand many processes ranging from star formation to the scale of the entire Universe," Reid said. The observing technique, called Very Long Baseline Interferometry (VLBI), was pioneered in 1967, but has come into continuous use only in the past 10-15 years. The National Science Foundation's Very Long Baseline Array (VLBA), a system of 10 radio-telescope antennas ranging from Hawaii to the Caribbean, was dedicated in 1993. There are other VLBI systems in Europe and Asia, and large radio telescopes around the world cooperate regularly to increase sensitivity. VLBI observations routinely produce images hundreds of times more detailed than those made at visible-light wavelengths by the Hubble Space Telescope. Several groups of researchers from across the globe use the VLBA to study stellar nurseries in our own Milky Way Galaxy and measure distances to regions where new stars are forming. The key has been to improve measurement accuracy to a factor of a hundred times better than that produced by the

  3. Design of an electric power system with incorporation of a phased array antenna for OLFAR

    NARCIS (Netherlands)

    Klein, J.M.; Budianu, A.; Bentum, Marinus Jan; Engelen, S.; Verhoeven, C.J.M.

    2013-01-01

    The Orbiting Low Frequency Antennas for Radio Astronomy (OLFAR) project is investigating the feasibility of an orbiting low frequency radio telescope. The radio telescope is formed using a swarm of nano-satellites equipped with astronomical antennas, conceivably orbiting the Moon or the second

  4. SAADA: Astronomical Databases Made Easier

    Science.gov (United States)

    Michel, L.; Nguyen, H. N.; Motch, C.

    2005-12-01

    Many astronomers wish to share datasets with their community but have not enough manpower to develop databases having the functionalities required for high-level scientific applications. The SAADA project aims at automatizing the creation and deployment process of such databases. A generic but scientifically relevant data model has been designed which allows one to build databases by providing only a limited number of product mapping rules. Databases created by SAADA rely on a relational database supporting JDBC and covered by a Java layer including a lot of generated code. Such databases can simultaneously host spectra, images, source lists and plots. Data are grouped in user defined collections whose content can be seen as one unique set per data type even if their formats differ. Datasets can be correlated one with each other using qualified links. These links help, for example, to handle the nature of a cross-identification (e.g., a distance or a likelihood) or to describe their scientific content (e.g., by associating a spectrum to a catalog entry). The SAADA query engine is based on a language well suited to the data model which can handle constraints on linked data, in addition to classical astronomical queries. These constraints can be applied on the linked objects (number, class and attributes) and/or on the link qualifier values. Databases created by SAADA are accessed through a rich WEB interface or a Java API. We are currently developing an inter-operability module implanting VO protocols.

  5. Extracting meaning from astronomical telegrams

    Science.gov (United States)

    Graham, Matthew; Conwill, L.; Djorgovski, S. G.; Mahabal, A.; Donalek, C.; Drake, A.

    2011-01-01

    The rapidly emerging field of time domain astronomy is one of the most exciting and vibrant new research frontiers, ranging in scientific scope from studies of the Solar System to extreme relativistic astrophysics and cosmology. It is being enabled by a new generation of large synoptic digital sky surveys - LSST, PanStarrs, CRTS - that cover large areas of sky repeatedly, looking for transient objects and phenomena. One of the biggest challenges facing these is the automated classification of transient events, a process that needs machine-processible astronomical knowledge. Semantic technologies enable the formal representation of concepts and relations within a particular domain. ATELs (http://www.astronomerstelegram.org) are a commonly-used means for reporting and commenting upon new astronomical observations of transient sources (supernovae, stellar outbursts, blazar flares, etc). However, they are loose and unstructured and employ scientific natural language for description: this makes automated processing of them - a necessity within the next decade with petascale data rates - a challenge. Nevertheless they represent a potentially rich corpus of information that could lead to new and valuable insights into transient phenomena. This project lies in the cutting-edge field of astrosemantics, a branch of astroinformatics, which applies semantic technologies to astronomy. The ATELs have been used to develop an appropriate concept scheme - a representation of the information they contain - for transient astronomy using aspects of natural language processing. We demonstrate that it is possible to infer the subject of an ATEL from the vocabulary used and to identify previously unassociated reports.

  6. Astronomical Signatures of Dark Matter

    Directory of Open Access Journals (Sweden)

    Paul Gorenstein

    2014-01-01

    Full Text Available Several independent astronomical observations in different wavelength bands reveal the existence of much larger quantities of matter than what we would deduce from assuming a solar mass to light ratio. They are very high velocities of individual galaxies within clusters of galaxies, higher than expected rotation rates of stars in the outer regions of galaxies, 21 cm line studies indicative of increasing mass to light ratios with radius in the halos of spiral galaxies, hot gaseous X-ray emitting halos around many elliptical galaxies, and clusters of galaxies requiring a much larger component of unseen mass for the hot gas to be bound. The level of gravitational attraction needed for the spatial distribution of galaxies to evolve from the small perturbations implied by the very slightly anisotropic cosmic microwave background radiation to its current web-like configuration requires much more mass than is observed across the entire electromagnetic spectrum. Distorted shapes of galaxies and other features created by gravitational lensing in the images of many astronomical objects require an amount of dark matter consistent with other estimates. The unambiguous detection of dark matter and more recently evidence for dark energy has positioned astronomy at the frontier of fundamental physics as it was in the 17th century.

  7. The League of Astronomers: Outreach

    Science.gov (United States)

    Paat, Anthony; Brandel, A.; Schmitz, D.; Sharma, R.; Thomas, N. H.; Trujillo, J.; Laws, C. S.; Astronomers, League of

    2014-01-01

    The University of Washington League of Astronomers (LOA) is an organization comprised of University of Washington (UW) undergraduate students. Our main goal is to share our interest in astronomy with the UW community and with the general public. The LOA hosts star parties on the UW campus and collaborates with the Seattle Astronomical Society (SAS) on larger Seattle-area star parties. At the star parties, we strive to teach our local community about what they can view in our night sky. LOA members share knowledge of how to locate constellations and use a star wheel. The relationship the LOA has with members of SAS increases both the number of events and people we are able to reach. Since the cloudy skies of the Northwest prevent winter star parties, we therefore focus our outreach on the UW Mobile Planetarium, an inflatable dome system utilizing Microsoft’s WorldWide Telescope (WWT) software. The mobile planetarium brings astronomy into the classrooms of schools unable to travel to the UW on-campus planetarium. Members of the LOA volunteer their time towards this project and we make up the majority of the Mobile Planetarium volunteers. Our outreach efforts allow us to connect with the community and enhance our own knowledge of astronomy.

  8. LGBT Workplace Issues for Astronomers

    Science.gov (United States)

    Kay, Laura E.; Danner, R.; Sellgren, K.; Dixon, V.; GLBTQastro

    2011-01-01

    Federal Equal Employment Opportunity laws and regulations do not provide protection from discrimination on the basis of sexual orientation or gender identity or gender expression. Sexual minority astronomers (including lesbian, gay, bisexual and transgender people; LGBT) can face additional challenges at school and work. Studies show that LGBT students on many campuses report experiences of harassment. Cities, counties, and states may or may not have statutes to protect against such discrimination. There is wide variation in how states and insurance plans handle legal and medical issues for transgender people. Federal law does not acknowledge same-sex partners, including those legally married in the U.S. or in other countries. Immigration rules in the U.S. (and many other, but not all) countries do not recognize same-sex partners for visas, employment, etc. State `defense of marriage act' laws have been used to remove existing domestic partner benefits at some institutions, or benefits can disappear with a change in governor. LGBT astronomers who change schools, institutions, or countries during their career may experience significant differences in their legal, medical, and marital status.

  9. Astronomers in the Chemist's War

    Science.gov (United States)

    Trimble, Virginia L.

    2012-01-01

    World War II, with radar, rockets, and "atomic" bombs was the physicists' war. And many of us know, or think we know, what our more senior colleagues did during it, with Hubble and Hoffleit at Aberdeen; M. Schwarzschild on active duty in Italy; Bondi, Gold, and Hoyle hunkered down in Dunsfeld, Surrey, talking about radar, and perhaps steady state; Greenstein and Henyey designing all-sky cameras; and many astronomers teaching navigation. World War I was The Chemists' War, featuring poison gases, the need to produce liquid fuels from coal on one side of the English Channel and to replace previously-imported dyesstuffs on the other. The talke will focus on what astronomers did and had done to them between 1914 and 1919, from Freundlich (taken prisoner on an eclipse expedition days after the outbreak of hostilities) to Edwin Hubble, returning from France without ever having quite reached the front lines. Other events bore richer fruit (Hale and the National Research Council), but very few of the stories are happy ones. Most of us have neither first nor second hand memories of The Chemists' War, but I had the pleasure of dining with a former Freundlich student a couple of weeks ago.

  10. Grote Reber, Radio Astronomy Pioneer, Dies

    Science.gov (United States)

    2002-12-01

    Grote Reber, one of the earliest pioneers of radio astronomy, died in Tasmania on December 20, just two days shy of his 91st birthday. Reber was the first person to build a radio telescope dedicated to astronomy, opening up a whole new "window" on the Universe that eventually produced such landmark discoveries as quasars, pulsars and the remnant "afterglow" of the Big Bang. His self- financed experiments laid the foundation for today's advanced radio-astronomy facilities. Grote Reber Grote Reber NRAO/AUI photo "Radio astronomy has changed profoundly our understanding of the Universe and has earned the Nobel Prize for several major contributions. All radio astronomers who have followed him owe Grote Reber a deep debt for his pioneering work," said Dr. Fred Lo, director of the National Radio Astronomy Observatory (NRAO). "Reber was the first to systematically study the sky by observing something other than visible light. This gave astronomy a whole new view of the Universe. The continuing importance of new ways of looking at the Universe is emphasized by this year's Nobel Prizes in physics, which recognized scientists who pioneered X-ray and neutrino observations," Lo added. Reber was a radio engineer and avid amateur "ham" radio operator in Wheaton, Illinois, in the 1930s when he read about Karl Jansky's 1932 discovery of natural radio emissions coming from outer space. As an amateur operator, Reber had won awards and communicated with other amateurs around the world, and later wrote that he had concluded "there were no more worlds to conquer" in radio. Learning of Jansky's discovery gave Reber a whole new challenge that he attacked with vigor. Analyzing the problem as an engineer, Reber concluded that what he needed was a parabolic-dish antenna, something quite uncommon in the 1930s. In 1937, using his own funds, he constructed a 31.4-foot-diameter dish antenna in his back yard. The strange contraption attracted curious attention from his neighbors and became

  11. Coping with Radio Frequency Interference

    Science.gov (United States)

    Lewis, B. M.

    2009-01-01

    The radio spectrum is a finite resource, on which humanity makes many demands. And pressure on it is ever increasing with the development of new technology and ideas for radio services. After all, we all benefit from wifi and cell phones. Radio astronomers have a small percentage of the spectrum allocated to them at octave intervals in the metre-centimetre bands, and at important frequencies, such as that of the 21cm line of HI. Signals from other services, as well as from our own poorly-engineered equipment, sometimes contaminate our bands: these signals constitute RFI. These may totally obliterate the astronomical signal, or, in the case of CLOUDSAT, may be capable of completely destroying a receiver, which introduces us to the new possibility of 'destructive interference'. A geo-stationary satellite can block access to a piece of sky from one site. Good equipment design eliminates self-inflicted interference, while physical separation often provides adequate practical mitigation at many frequencies. However, new observatories end up being located in the West Australian desert or Antarctica. In future they may be on the back side of the Moon. But there is no Earth-bound protection via physical separation against satellite signals. Some mitigation can be achieved by frequent data dumps and the excision of RFI, or by real-time detection and blanking of the receiver, or by more sophisticated algoriths. Astronomers of necessity aim to achieve mitigation via coordination, at the local level, and by participating in spectrum management at the national and international levels. This involves them spending a lot of time in Geneva at the International Telegraphic Union protecting their access to spectrum, and access to clean spectrum from the L3 point and the far side of the Moon.

  12. Amateur Astronomers: Secret Agents of EPO

    Science.gov (United States)

    Berendsen, M.; White, V.; Devore, E.; Reynolds, M.

    2008-06-01

    Amateur astronomers prime the public to be more interested, receptive, and excited about space science, missions, and programs. Through recent research and targeted programs, amateur astronomy outreach is being increasingly recognized by professional astronomers, educators, and other amateurs as a valued and important service. The Night Sky Network program, administered by the ASP, is the first nationwide research-based program specifically targeted to support outreach by amateur astronomers. This Network of trained and informed amateur astronomers can provide a stimulating introduction to your EPO programs as Network members share the night sky with families, students, and youth groups.

  13. Astronomical Symbolism in Australian Aboriginal Rock Art

    Science.gov (United States)

    Norris, Ray P.; Hamacher, Duane W.

    2011-05-01

    Traditional Aboriginal Australian cultures include a significant astronomical component, perpetuated through oral tradition and ceremony. This knowledge has practical navigational and calendrical functions, and sometimes extends to a deep understanding of the motion of objects in the sky. Here we explore whether this astronomical tradition is reflected in the rock art of Aboriginal Australians. We find several plausible examples of depictions of astronomical figures and symbols, and also evidence that astronomical observations were used to set out stone arrangements. However, we recognise that the case is not yet strong enough to make an unequivocal statement, and describe our plans for further research.

  14. Storing Astronomical Information on the Romanian Territory

    Science.gov (United States)

    Stavinschi, M.; Mioc, V.

    2004-12-01

    Romanian astronomy has a more than 2000-year old tradition, which is, however, little known abroad. The first known archive of astronomical information is the Dacian sanctuary at Sarmizegetusa Regia, erected in the first century AD, having similarities with that of Stonehenge. After a gap of more than 1000 years, more sources of astronomical information become available, mainly records of astronomical events. Monasteries were the safest storage places of these genuine archives. We present a classification of the ways of storing astronomical information, along with characteristic examples.

  15. FITSManager: Management of Personal Astronomical Data

    Science.gov (United States)

    Cui, Chenzhou; Fan, Dongwei; Zhao, Yongheng; Kembhavi, Ajit; He, Boliang; Cao, Zihuang; Li, Jian; Nandrekar, Deoyani

    2011-07-01

    With the increase of personal storage capacity, it is easy to find hundreds to thousands of FITS files in the personal computer of an astrophysicist. Because Flexible Image Transport System (FITS) is a professional data format initiated by astronomers and used mainly in the small community, data management toolkits for FITS files are very few. Astronomers need a powerful tool to help them manage their local astronomical data. Although Virtual Observatory (VO) is a network oriented astronomical research environment, its applications and related technologies provide useful solutions to enhance the management and utilization of astronomical data hosted in an astronomer's personal computer. FITSManager is such a tool to provide astronomers an efficient management and utilization of their local data, bringing VO to astronomers in a seamless and transparent way. FITSManager provides fruitful functions for FITS file management, like thumbnail, preview, type dependent icons, header keyword indexing and search, collaborated working with other tools and online services, and so on. The development of the FITSManager is an effort to fill the gap between management and analysis of astronomical data.

  16. A polarized fast radio burst at low Galactic latitude

    OpenAIRE

    Rowlinson, A.; O'Sullivan, Michael; Anghinolfi, Marco; Anton, G.; Avgitas, T.; Bertin, V.; Puricelli, Stefano; Coniglione, R.; Gleixner, A; Lefèvre, Dominique; Michael, Turner; Pellegrino, Carlo; Piattelli, P.; Sanchez Losa, Agustín; Schnabel, J.

    2017-01-01

    This article has been accepted for publication in Monthly Notices of the Royal Astronomical Society ©: 2017 The Authors. Published by Oxford University Press on behalf of the Royal Astronomical Society. All rights reserved. We report on the discovery of a new fast radio burst (FRB), FRB 150215, with the Parkes radio telescope on 2015 February 15. The burst was detected in real time with a dispersion measure (DM) of 1105.6 ± 0.8 pc cm-3;3, a pulse duration of 2.8+1.2-0.25 ms, and a measured...

  17. A Brief History of Radio Astronomy in the USSR A Collection of Scientific Essays

    CERN Document Server

    Salomonovich, A; Samanian, V; Shklovskii, I; Sorochenko, R; Troitskii, V; Kellermann, K; Dubinskii, B; Kaidanovskii, N; Kardashev, N; Kobrin, M; Kuzmin, A; Molchanov, A; Pariiskii, Yu; Rzhiga, O

    2012-01-01

    This translation from Russian makes the history of radio astronomy in the USSR available in the English language for the first time. The book includes descriptions of the antennas and instrumentation used in the USSR, the astronomical discoveries, as well as interesting personal backgrounds of many of the early key players in Soviet radio astronomy. A Brief History of Radio Astronomy in the USSR is a collection of memoirs recounting an interesting but largely still dark era of Soviet astronomy. The arrangement of the essays is determined primarily by the time when radio astronomy studies began at the institutions involved. These include the Lebedev Physical Institute (FIAN), Gorkii State University and the affiliated Physical-Technical Institute (GIFTI), Moscow State University Sternberg Astronomical institute (GAISH) and Space Research Institute (IKI), the Department of Radio Astronomy of the Main Astronomical Observatory in Pulkovo (GAO), Special Astrophysical Observatory (SAO), Byurakan Astrophysical Obse...

  18. Phase Synchronization for the Mid-Frequency Square Kilometre Array Telescope

    Science.gov (United States)

    Schediwy, Sascha; Gozzard, David; Stobie, Simon; Gravestock, Charles; Whitaker, Richard; Alachkar, Bassem; Malan, Sias; Boven, Paul; Grainge, Keith

    2018-01-01

    The Square Kilometre Array (SKA) project is an international effort to build the world’s most sensitive radio telescope operating in the 50 MHz to 14 GHz frequency range. Construction of the SKA has been divided into phases, with the first phase (SKA1) accounting for the first 10% of the telescope's receiving capacity. During SKA1, a low-frequency aperture array comprising over a hundred thousand individual dipole antenna elements will be constructed in Western Australia (SKA1-low), while an array of 197 parabolic-dish antennas, incorporating the 64 dishes of MeerKAT, will be constructed in South Africa (SKA1-mid).Radio telescope arrays such as the SKA require phase-coherent reference signals to be transmitted to each antenna site in the array. In the case of the SKA1-mid, these reference signals will be generated at a central site and transmitted to the antenna sites via fiber-optic cables up to 175 km in length. Environmental perturbations affect the optical path length of the fiber and act to degrade the phase stability of the reference signals received at the antennas, which has the ultimate effect of reducing the fidelity and dynamic range of the data.Since 2011, researchers at the University of Western Australia (UWA) have led the development of an actively-stabilized phase-synchronization system designed specifically to meet the scientific needs and technical challenges of the SKA telescope. Recently this system has been select as the official phase synchronization system for the SKA1-mid telescope. The system is an evolution of Atacama Large Millimeter Array’s distributed ‘photonic local oscillator system’, incorporating key advances made by the international frequency metrology community over the last decade, as well as novel innovations developed by UWA researchers.In this presentation I will describe the technical details of the system; outline how the system's performance was tested using metrology techniques in a laboratory setting, on 186 km

  19. Astronomical theory of climate change

    Energy Technology Data Exchange (ETDEWEB)

    Berger, A.; Loutre, M.F. [Universite Catholique de Louvain (UCL), Louvain-la-Neuve (Belgium). Inst. d' Astronomie et de Geophysique G. Lemaitre

    2004-12-01

    The astronomical theory of paleo-climates aims to explain the climatic variations occurring with quasi-periodicities lying between tens and hundreds of thousands of years. The origin of these quasi-cycles lies in the astronomically driven changes in the latitudinal and seasonal distributions of the energy that the Earth receives from the Sun. These changes are then amplified by the feedback mechanisms which characterize the natural behaviour of the climate system like those involving the albedo-, the water vapor-, and the vegetation- temperature relationships. Climate models of different complexities are used to explain the chain of processes which finally link the long-term variations of three astronomical parameters to the long-term climatic variations at time scale of tens to hundreds of thousands of years. In particular, sensitivity analysis to the astronomically driven insolation changes and to the CO{sub 2} atmospheric concentrations have been performed with the 2-dimension climate model of Louvain-la-Neuve. It could be shown that this model simulates more or less correctly the entrance into glaciation around 2.75 million year (Myr) BP (before present), the late Pliocene-early Pleistocene 41-kyr (thousand years) cycle, the emergence of the 100-kyr cycle around 850 kyr BP and the glacial-interglacial cycles of the last 600 kyr. During the Late Pliocene (in an ice-free - warm world) ice sheets can only develop during times of sufficiently low summer insolation. This occurs during large eccentricity times when climatic precession and obliquity combine to obtain such low values, leading to the 41-kyr period between 3 and 1 million years BP. On the contrary in a glacial world, ice sheets persist most of the time except when insolation is very high in polar latitudes, requiring large eccentricity again, but leading this time to interglacial and finally to the 100-kyr period of the last 1 Myr. Using CO{sub 2} scenarios, it has been shown that stage 11 and stage 1

  20. An astronomical observatory for Peru

    Science.gov (United States)

    del Mar, Juan Quintanilla; Sicardy, Bruno; Giraldo, Víctor Ayma; Callo, Víctor Raúl Aguilar

    2011-06-01

    Peru and France are to conclude an agreement to provide Peru with an astronomical observatory equipped with a 60-cm diameter telescope. The principal aims of this project are to establish and develop research and teaching in astronomy. Since 2004, a team of researchers from Paris Observatory has been working with the University of Cusco (UNSAAC) on the educational, technical and financial aspects of implementing this venture. During an international astronomy conference in Cusco in July 2009, the foundation stone of the future Peruvian Observatory was laid at the top of Pachatusan Mountain. UNSAAC, represented by its Rector, together with the town of Oropesa and the Cusco regional authority, undertook to make the sum of 300,000€ available to the project. An agreement between Paris Observatory and UNSAAC now enables Peruvian students to study astronomy through online teaching.

  1. Asteroids astronomical and geological bodies

    CERN Document Server

    Burbine, Thomas H

    2016-01-01

    Asteroid science is a fundamental topic in planetary science and is key to furthering our understanding of planetary formation and the evolution of the Solar System. Ground-based observations and missions have provided a wealth of new data in recent years, and forthcoming missions promise further exciting results. This accessible book presents a comprehensive introduction to asteroid science, summarising the astronomical and geological characteristics of asteroids. The interdisciplinary nature of asteroid science is reflected in the broad range of topics covered, including asteroid and meteorite classification, chemical and physical properties of asteroids, observational techniques, cratering, and the discovery of asteroids and how they are named. Other chapters discuss past, present and future space missions and the threat that these bodies pose for Earth. Based on an upper-level course on asteroids and meteorites taught by the author, this book is ideal for students, researchers and professional scientists ...

  2. Preparing Colorful Astronomical Images II

    Science.gov (United States)

    Levay, Z. G.; Frattare, L. M.

    2002-12-01

    We present additional techniques for using mainstream graphics software (Adobe Photoshop and Illustrator) to produce composite color images and illustrations from astronomical data. These techniques have been used on numerous images from the Hubble Space Telescope to produce photographic, print and web-based products for news, education and public presentation as well as illustrations for technical publication. We expand on a previous paper to present more detail and additional techniques, taking advantage of new or improved features available in the latest software versions. While Photoshop is not intended for quantitative analysis of full dynamic range data (as are IRAF or IDL, for example), we have had much success applying Photoshop's numerous, versatile tools to work with scaled images, masks, text and graphics in multiple semi-transparent layers and channels.

  3. IAU Public Astronomical Organisations Network

    Science.gov (United States)

    Canas, Lina; Cheung, Sze Leung

    2015-08-01

    The Office for Astronomy Outreach has devoted intensive means to create and support a global network of public astronomical organisations around the world. Focused on bringing established and newly formed amateur astronomy organizations together, providing communications channels and platforms for disseminating news to the global community and the sharing of best practices and resources among these associations around the world. In establishing the importance that these organizations have for the dissemination of activities globally and acting as key participants in IAU various campaigns social media has played a key role in keeping this network engaged and connected. Here we discuss the implementation process of maintaining this extensive network, the processing and gathering of information and the interactions between local active members at a national and international level.

  4. Astronomical Data in Undergraduate courses

    Science.gov (United States)

    Clarkson, William I.; Swift, Carrie; Hughes, Kelli; Burke, Christopher J. F.; Burgess, Colin C.; Elrod, Aunna V.; Howard, Brittany; Stahl, Lucas; Matzke, David; Bord, Donald J.

    2016-06-01

    We present status and plans for our ongoing efforts to develop data analysis and problem-solving skills through Undergraduate Astronomy instruction. While our initiatives were developed with UM-Dearborn’s student body primarily in mind, they should be applicable for a wide range of institution and of student demographics. We focus here on two strands of our effort.Firstly, students in our Introductory Astronomy (ASTR 130) general-education course now perform several “Data Investigations”, in which they interrogate the Hubble Legacy Archive to illustrate important course concepts. This was motivated in part by the realization that typical public data archives now include tools to interrogate the observations that are sufficiently accessible that introductory astronomy students can use them to perform real science, albeit mostly at a descriptive level. We are continuing to refine these investigations, and, most importantly, to critically assess their effectiveness in terms of the student learning outcomes we wish to achieve. This work is supported by grant HST-EO-13758, provided by NASA through a grant from the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS 5-26555.Secondly, at the advanced-undergraduate level, students taking courses in our Astronomy minor are encouraged to gain early experience in techniques of astronomical observation and analysis that are used by professionals. We present two example projects from the Fall 2015 iteration of our upper-division course ASTR330 (The Cosmic Distance Ladder), one involving Solar System measurements, the second producing calibrated aperture photometry. For both projects students conducted, analysed, and interpreted observations using our 0.4m campus telescope, and used many of the same analysis tools as professional astronomers. This work is supported partly from a Research Initiation and Seed grant from the

  5. Solar Radio

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Scientists monitor the structure of the solar corona, the outer most regions of the Sun's atmosphere, using radio waves (100?s of MHz to 10?s of GHz). Variations in...

  6. Radio astronomy

    International Nuclear Information System (INIS)

    Parijskij, Y.N.; Gossachinskij, I.V.; Zuckerman, B.; Khersonsky, V.K.; Pustilnik, S.; Robinson, B.J.

    1976-01-01

    A critical review of major developments and discoveries in the field of radioastronomy during the period 1973-1975 is presented. The report is presented under the following headings:(1) Continuum radiation from the Galaxy; (2) Neutral hydrogen, 21 cm (galactic and extragalactic) and recombination lines; (3) Radioastronomy investigations of interstellar molecules; (4) Extragalactic radio astronomy and (6) Development in radio astronomy instruments. (B.R.H.)

  7. A Refined Astronomically Calibrated 40Ar/39Ar Age for Fish Canyon Sanidine

    DEFF Research Database (Denmark)

    Rivera, Tiffany; Storey, Michael; Zeeden, Christian

    2011-01-01

    Intercalibration between the astronomical and radio-isotopic dating methods provides a means to improving accuracy and reducing uncertainty of an integrated, multi-chronometer geologic timescale. Here we report a high-precision 40Ar/39Ar age for the Fish Canyon sanidine (FCs) neutron fluence...... sanidine age of 0.7674±0.0022 Ma (2σ, external errors) is indistinguishable from the ID-TIMS U/Pb zircon age (0.7671±0.0019 Ma). The consistency between the astronomically calibrated 40Ar/39Ar sanidine age and U/Pb zircon age for this Quaternary unit suggests that agreement between these two radio-isotopic...... dating techniques is now achievable at better than±0.3% (2σ) in the youngest part of geologic time (

  8. Radio Frequency Interference Mitigation

    Science.gov (United States)

    An, T.; Chen, X.; Mohan, P.; Lao, B. Q.

    2017-09-01

    The observational facilities of radio astronomy keep constant upgrades and developments to achieve better capabilities including increasing the time of the data recording and frequency resolutions, and increasing the receiving and recording bandwidth. However in contrast, only a limited spectrum resource has been allocated to radio astronomy by the International Telecommunication Union, resulting in that the radio observational instrumentations are inevitably exposed to undesirable radio frequency interference (RFI) signals which originate mainly from the terrestrial human activity and are becoming stronger with time. RFIs degrade the quality of data and even lead to invalid data. The impact of RFIs on scientific outcome becomes more and more serious. In this article, the requirement for RFI mitigation is motivated, and the RFI characteristics, mitigation techniques, and strategies are reviewed. The mitigation strategies adopted at some representative observatories, telescopes, and arrays are also introduced. The advantages and shortcomings of the four classes of RFI mitigation strategies are discussed and presented, applicable at the connected causal stages: preventive, pre-detection, pre-correlation, and post-correlation. The proper identification and flagging of RFI is the key to the reduction of data loss and improvement in data quality, and is also the ultimate goal of developing RFI mitigation technique. This can be achieved through a strategy involving a combination of the discussed techniques in stages. The recent advances in the high speed digital signal processing and high performance computing allow for performing RFI excision of the large data volumes generated from large telescopes or arrays in both real time and offline modes, aiding the proposed strategy.

  9. Astronomers See First Stages of Planet-Building Around Nearby Star

    Science.gov (United States)

    2005-06-01

    Interstellar travelers might want to detour around the star system TW Hydrae to avoid a messy planetary construction site. Astronomer David Wilner of the Harvard-Smithsonian Center for Astrophysics (CfA) and his colleagues have discovered that the gaseous protoplanetary disk surrounding TW Hydrae holds vast swaths of pebbles extending outward for at least 1 billion miles. These rocky chunks should continue to grow in size as they collide and stick together until they eventually form planets. Dust Disk Graphic Artist's Conception of Dusty Disk Around Young Star TW Hydrae CREDIT: Bill Saxton, NRAO/AUI/NSF (Click on image for larger version 1.8 MB) "We're seeing planet building happening right before our eyes," said Wilner. "The foundation has been laid and now the building materials are coming together to make a new solar system." Wilner used the National Science Foundation's Very Large Array to measure radio emissions from TW Hydrae. He detected radiation from a cold, extended dust disk suffused with centimeter-sized pebbles. Such pebbles are a prerequisite for planet formation, created as dust collects together into larger and larger clumps. Over millions of years, those clumps grow into planets. "We're seeing an important step on the path from interstellar dust particles to planets," said Mark Claussen (NRAO), a co-author on the paper announcing the discovery. "No one has seen this before." A dusty disk like that in TW Hydrae tends to emit radio waves with wavelengths similar to the size of the particles in the disk. Other effects can mask this, however. In TW Hydrae, the astronomers explained, both the relatively close distance of the system and the stage of the young star's evolution are just right to allow the relationship of particle size and wavelength to prevail. The scientists observed the young star's disk with the VLA at several centimeter-range wavelengths. "The strong emission at wavelengths of a few centimeters is convincing evidence that particles of

  10. A SURVEY OF ASTRONOMICAL RESEARCH: A BASELINE FOR ASTRONOMICAL DEVELOPMENT

    International Nuclear Information System (INIS)

    Ribeiro, V. A. R. M.; Russo, P.; Cárdenas-Avendaño, A.

    2013-01-01

    Measuring scientific development is a difficult task. Different metrics have been put forward to evaluate scientific development; in this paper we explore a metric that uses the number of peer-reviewed, and when available non-peer-reviewed, research articles as an indicator of development in the field of astronomy. We analyzed the available publication record, using the Smithsonian Astrophysical Observatory/NASA Astrophysics Database System, by country affiliation in the time span between 1950 and 2011 for countries with a gross national income of less than 14,365 USD in 2010. This represents 149 countries. We propose that this metric identifies countries in ''astronomical development'' with a culture of research publishing. We also propose that for a country to develop in astronomy, it should invest in outside expert visits, send its staff abroad to study, and establish a culture of scientific publishing. Furthermore, we propose that this paper may be used as a baseline to measure the success of major international projects, such as the International Year of Astronomy 2009

  11. Nikolay N. Donitch - the astronomer

    Science.gov (United States)

    Gaina, Alex B.; Volyanskaya, M. Yu.

    1999-08-01

    The article is devoted to milestones of life and scientific activity of the eminent astronomer Nikolay Nikolaevich Donitch (Nicolae N. Donici) (1874-1956), a graduate from the Odessa (Novorossiski) university. He was a wellknown expert in the field of reseacrh of objects of Solar system. A person highly cultured, which built the first in Bessarabia (actually a part of the Republic of Moldova) observatory. He was borne in Kishinev (Chisinau) in a nobles family of notable Moldavian landersmen. N.D. graduated from the Richelieu lyceym in Odessa and afterwards, in 1897, graduated from the Odessa (Novorossiysky) University. A.K. Kononovich (1850-1910)headed the chair of astronomy and the Observatory at that time - a foremost authority in the field of astrophysics and stellar astronomy. Many of his disciples became eminent scientists of their time. N. Donitch was among them. N.D. worked till 1918 at Pulkovo Observatory and became a master in the field of studying of such phenomena as solar and lunar eclipses. To observe the Sun N.D., could afford to design and manufacture a spectroheliograph, the first in Russia, with the assistance of a famous Odessa mechanic J.A. Timchenko. This instrument enabled him to obtain topquality photos of the Sun's surface and prominences. It was mounted together with coelostat in the private observatory of N.D. , built in the village Staryie Doubossary in 1908. Besides the heliograoph, the observatory was equiped with a five inch refractor-equatorial with numerous instruments for various observations. Of the other instruments should be mentioned : "a comet triplet" - an instrument consisting of guiding refractor, a photographic camera and a spectrograph with an objective prism. N.D. was lucky enough to observe rare astronomical phenomena. He observed the transit of Mercury through the disk of the Sun on November 14, 1907 and showed the athmosphere absence around this planet, observed the Halley's comet in 1910, the bright Pons-Winneke comet

  12. Resurfacing the Jodrell Bank Mk II radio telescope

    Science.gov (United States)

    Spencer, R. E.; Haggis, J. S.; Morrison, I.; Davis, R. J.; Melling, R. J.

    The improvement of the short-wavelength performance of the Jodrell Bank Mk II radio telescope is described. A final rms profile error of 0.6 mm was achieved due to the invention of an inexpensive technique of panel construction and measurement combined with the use of radio-astronomical holographic techniques to measure the telescope under actual operating conditions. Some further improvements to extend the short wavelength performance are suggested.

  13. First use of a HyViSI H4RG for Astronomical Observations

    Energy Technology Data Exchange (ETDEWEB)

    Simms, Lance M.; /SLAC; Figer, Donald F.; Hanold, Brandon J.; Kerr, Daniel J.; /Rochester Imaging Lab.; Gilmore, D.Kirk; Kahn, Steven M.; /SLAC; Tyson, J.Anthony; /UC,

    2007-09-25

    We present the first astronomical results from a 4K2 Hybrid Visible Silicon PIN array detector (HyViSI) read out with the Teledyne Scientific and Imaging SIDECAR ASIC. These results include observations of astronomical standards and photometric measurements using the 2.1m KPNO telescope. We also report results from a test program in the Rochester Imaging Detector Laboratory (RIDL), including: read noise, dark current, linearity, gain, well depth, quantum efficiency, and substrate voltage effects. Lastly, we highlight results from operation of the detector in window read out mode and discuss its potential role for focusing, image correction, and use as a telescope guide camera.

  14. Nanosecond-level time synchronization of autonomous radio detector stations for extensive air showers

    NARCIS (Netherlands)

    Aab, A.; Abreu, P.; Aglietta, M.; Ahn, E. J.; Al Samarai, I.; Albuquerque, I. F. M.; Allekotte, I.; Messina, S.; Scholten, O.; van den Berg, A.M.

    To exploit the full potential of radio measurements of cosmic-ray air showers at MHz frequencies, a detector timing synchronization within 1 ns is needed. Large distributed radio detector arrays such as the Auger Engineering Radio Array (AERA) rely on timing via the Global Positioning System (GPS)

  15. Astronomical imaging with a low temperature InSb charge injection device (CID)

    International Nuclear Information System (INIS)

    Rouan, D.; Lacombe, F.; Tiphene, D.; Stefanovitch, D.; Phan van, D.

    1986-01-01

    InSb charge injection device (CID) technology focal plane arrays employ two coupled MIS capacitors which collect and store photon-generated charge carriers. Attention is presently given to two-dimensional arrays for 77 K and 4 K operating temperatures in astronomical applications; two such prototypes for ground observations have been developed for use with a 2-m telescope. A CID InSb array is noted to be a useful candidate for the proposed IR Space Observatory's focal plane camera. 7 references

  16. A repeating fast radio burst.

    Science.gov (United States)

    Spitler, L G; Scholz, P; Hessels, J W T; Bogdanov, S; Brazier, A; Camilo, F; Chatterjee, S; Cordes, J M; Crawford, F; Deneva, J; Ferdman, R D; Freire, P C C; Kaspi, V M; Lazarus, P; Lynch, R; Madsen, E C; McLaughlin, M A; Patel, C; Ransom, S M; Seymour, A; Stairs, I H; Stappers, B W; van Leeuwen, J; Zhu, W W

    2016-03-10

    Fast radio bursts are millisecond-duration astronomical radio pulses of unknown physical origin that appear to come from extragalactic distances. Previous follow-up observations have failed to find additional bursts at the same dispersion measure (that is, the integrated column density of free electrons between source and telescope) and sky position as the original detections. The apparent non-repeating nature of these bursts has led to the suggestion that they originate in cataclysmic events. Here we report observations of ten additional bursts from the direction of the fast radio burst FRB 121102. These bursts have dispersion measures and sky positions consistent with the original burst. This unambiguously identifies FRB 121102 as repeating and demonstrates that its source survives the energetic events that cause the bursts. Additionally, the bursts from FRB 121102 show a wide range of spectral shapes that appear to be predominantly intrinsic to the source and which vary on timescales of minutes or less. Although there may be multiple physical origins for the population of fast radio bursts, these repeat bursts with high dispersion measure and variable spectra specifically seen from the direction of FRB 121102 support an origin in a young, highly magnetized, extragalactic neutron star.

  17. A novel type of very long baseline astronomical intensity interferometer

    Science.gov (United States)

    Borra, Ermanno F.

    2013-12-01

    This article presents a novel type of very long baseline astronomical interferometer that uses the fluctuations, as a function of time, of the intensity measured by a quadratic detector, which is a common type of astronomical detector. The theory on which the technique is based is validated by laboratory experiments. Its outstanding principal advantages comes from the fact that the angular structure of an astronomical object is simply determined from the visibility of the minima of the spectrum of the intensity fluctuations measured by the detector, as a function of the frequency of the fluctuations, while keeping the spacing between mirrors constant. This would allow a simple setup capable of high angular resolutions because it could use an extremely large baseline. Another major interest is that it allows for a more efficient use of telescope time because observations at a single baseline are sufficient, while amplitude and intensity interferometers need several observations at different baselines. The fact that one does not have to move the telescopes would also allow detecting faster time variations because having to move the telescopes sets a lower limit to the time variations that can be detected. The technique uses wave interaction effects and thus has some characteristics in common with intensity interferometry. A disadvantage of the technique, like in intensity interferometry, is that it needs strong sources if observing at high frequencies (e.g. the visible). This is a minor disadvantage in the radio region. At high frequencies, this disadvantage is mitigated by the fact that, like in intensity interferometry, the requirements of the optical quality of the mirrors used are far less severe than in amplitude interferometry so that poor quality large reflectors (e.g. Cherenkov telescopes) can be used in the optical region.

  18. Reporting Astronomical Discoveries: Past, Now, and Future

    Science.gov (United States)

    Yamaoka, Hitoshi; Green, Daniel W. E.; Samus, Nikolai N.; West, Richard

    2015-08-01

    Many new astronomical objects have been discovered over the years by amateur astronomers, and this continues to be the case. They have traditionally reported them (as have professional astronomers) to the Central Bureau for Astronomical Telegrams (CBAT), which was established in the 19th century. This procedure has worked very well throughout the 20th century, moving under the umbrella of the newly established IAU in 1920. The discoverers have been honored by the formal announcement of their discoveries in the publications of the CBAT.In recent years, some professional research groups have established other ways of announcing their discoveries of explosive objects such as novae and supernovae; some do not now report their discoveries or spectroscopic confirmations of the transients to the CBAT, including often spectroscopic reports of objects posted to the CBAT "Transient Objects Confirmation Page" -- the highly successful TOCP webpage, which assigns official positional designations to new transients posted there by approved, registered users. This leads to a delay in formal announcements of discoveries by amateur astronomers in many cases, as well as inconsistent designations being put into use by individual groups. Amateur astronomers are feeling frustrated about this situation, and they hope that the IAU will help to settle the situation.We have proposed the new IAU commission NC-52, which will treat these phenomena in a continuation of Commission 6, through the CBAT. We hope to continuously support the reporting of the discoveries by amateur astronomers, as well as professional astronomers, who all deserve and desire proper recognition. Our strategy will maintain the firm trust between the amateur and professional astronomers, which is necessary for true collaboration. The plan is for the CBAT to work with collaborators to assure that discoveries posted on the TOCP are promptly designated and announced by the CBAT, even when confirmations are made elsewhere

  19. Astronomical Knowledge in Holy Books

    Science.gov (United States)

    Farmanyan, Sona V.; Mickaelian, Areg M.

    2015-08-01

    We investigate religious myths related to astronomy from different cultures in an attempt to identify common subjects and characteristics. The paper focuses on astronomy in religion. The initial review covers records from Holy books about sky related superstitious beliefs and cosmological understanding. The purpose of this study is to introduce sky related religious and national traditions (particularly based on different calendars; Solar or Lunar). We carried out a comparative study of astronomical issues contained in a number of Holy books: Ancient Egyptian Religion (Pyramid Texts), Zoroastrianism (Avesta), Hinduism (Vedas), Buddhism (Tipitaka), Confucianism (Five Classics), Sikhism (Guru Granth Sahib), Christianity (Bible), Islam (Quran), Druidism (Mabinogion) and Maya Religion (Popol Vuh). These books include various information on the creation of the Universe, Sun and Moon, the age of the Universe, Cosmic sizes, understanding about the planets, stars, Milky Way and description of the Heavens in different religions. We come to the conclusion that the perception of celestial objects varies from culture to culture, and from religion to religion and preastronomical views had a significant impact on humankind, particularly on religious diversities. We prove that Astronomy is the basis of cultures, and that national identity and mythology and religion were formed due to the special understanding of celestial objects.

  20. The Undergraduate Research Resources at the Pisgah Astronomical Research Institute

    Science.gov (United States)

    Cline, J. Donald; Castelaz, Michael W.

    2016-01-01

    Pisgah Astronomical Research Institute (PARI), a former NASA tracking station located in western North Carolina, has been offering programs, campus, and instrument use for undergraduate research and learning experiences since 2000. Over these years, PARI has collaborated with universities and colleges in the Southeastern U.S. Sharing its campus with institutions of higher learning is a priority for PARI as part of its mission to "to providing hands-on educational and research opportunities for a broad cross-section of users in science, technology, engineering and math (STEM) disciplines."PARI is a 200 acre campus for environmental, earth, geological, physical, and astronomical sciences. For example, the PARI 26-m and 4.6-m radio telescopes are excellent for teaching electromagnetic theory, spectroscopy, atomic and molecular emission processes, and general physics and astronomy concepts. The PARI campus has lab and office space, data centers with high speed internet, distance learning capabilities, radio and optical telescopes, earth science sensors, housing and cafeteria.Also, the campus is in an excellent spot for environmental and biological sciences lab and classroom experiences for students. The campus has the capability to put power and Internet access almost anywhere on its 200 acre campus so experiments can be set up in a protected area of a national forest. For example, Earthscope operates a Plate Boundary Observatory sensor on campus to measure plate tectonic motion. And, Clemson University has an instrument measuring winds and temperatures in the Thermsophere. The use of thePARI campus is limited only by the creativity faculty to provide a rich educational environment for their students. An overview of PARI will be presented along with a summary of programs, and a summary of undergraduate research experiences over the past 15 years. Access to PARI and collaboration possibilities will be presented.

  1. Radio astronomy

    CERN Document Server

    Alder, Berni

    1975-01-01

    Methods in Computational Physics, Volume 14: Radio Astronomy is devoted to the role of the digital computer both as a control device and as a calculator in addressing problems related to galactic radio noise. This volume contains four chapters and begins with a technical description of the hardware and the special data-handling problems of using radioheliography, with an emphasis on a selection of observational results obtained with the Culgoora radioheliograph and their significance to solar physics and to astrophysics in general. The subsequent chapter examines interstellar dispersion, i

  2. Mingantu, 18th-Century Mongol Astronomer and Radioheliograph Namesake

    Science.gov (United States)

    Pasachoff, Jay M.

    2013-01-01

    The 18th-century Mongol astronomer Mingantu (1692-1765) has been honored with a city named after him and a nearby solar telescope array. During the IAU/Beijing, my wife and I went to the new Chinese solar radioheliograph, the Mingantu Observing Station, in Inner Mongolia, ~400 km northwest of Beijing, a project of the National Astronomical Observatories, Chinese Academy of Sciences. It currently contains 40 dishes each 4.5 m across, with a correlator from Beijing. Within a year, 60 2-m dishes will be added. We passed by the 12-century ruins of Xanadu (about 20 km north of Zhangbei) about halfway. The radioheliograph is in a plane about 1 km across, forming a three-armed spiral for interferometric solar mapping, something colleagues and I had carried out with the Jansky Very Large Array, taking advantage of the lunar occultation before annularity at the 20 May 2012 solar eclipse. In the central square of Mingantu city, a statue ~10-m high of the Mongol astronomer Mingantu appears. Its base bears a plaque ~1-m high of IAU Minor Planet Circular MPC 45750 announcing the naming in 2002 of asteroid 28242 Mingantu, discovered at a Chinese observatory in 1999. Mingantu carried out orbital calculations, mapping, mathematical work on infinite series, and other scientific research. He is honored by a modern museum behind the statue. The museum's first 40% describes Mingantu and his work, and is followed by some artifacts of the region from thousands of years ago. The final, large room contains a two-meter-square scale model of the radioheliograph, flat-screen televisions running Solar Dynamics Observatory and other contemporary visualizations, orreries and other objects, and large transparencies of NASA and other astronomical imagery. See my post at http://www.skyandtelescope.com/community/skyblog/newsblog/ specfically Astro-Sightseeing_in_Inner_Mongolia-167712965.html. We thank Yihua Yan for arranging the visit and Wang Wei (both NAOC) for accompanying us. My solar research

  3. Multi-criteria decision analysis integrated with GIS for radio ...

    African Journals Online (AJOL)

    Multi-criteria decision analysis integrated with GIS for radio astronomical observatory site selection in peninsular of Malaysia. R Umar, Z.Z. Abidin, Z.A. Ibrahim, M.K.A. Kamarudin, S.N. Hazmin, A Endut, H Juahir ...

  4. Bayesian estimation for ionospheric calibration in radio astronomy

    NARCIS (Netherlands)

    Van der Tol, S.

    2009-01-01

    Radio astronomical observations at low frequencies (< 250 MHz), can be severely distorted by fluctuations in electron density in the ionosphere. The free electrons cause a phase change of electromagnetic waves traveling through the ionosphere. This effect increases for lower frequencies. For this

  5. A radio and optical study of Molonglo radio sources

    Science.gov (United States)

    Ishwara-Chandra, C. H.; Saikia, D. J.; McCarthy, P. J.; van Breugel, W. J. M.

    2001-05-01

    We present multi-wavelength radio observations with the Very Large Array, and narrow- and broad-band optical observations with the 2.5-m telescope at the Las Campanas Observatory, of a well-defined sample of high-luminosity Fanaroff-Riley class II radio galaxies and quasars, selected from the Molonglo Reference Catalogue 1-Jy sample. These observations were carried out as part of a programme to investigate the effects of orientation and environment on some of the observed properties of these sources. We examine the dependence of the Liu-Pooley relationship, which shows that radio lobes with flatter radio spectra are less depolarized, on size, identification and redshift, and show that it is significantly stronger for smaller sources, with the strength of the relationship being similar for both radio galaxies and quasars. In addition to Doppler effects, there appear to be intrinsic differences between the lobes on opposite sides. We discuss the asymmetry in brightness and location of the hotspots, and present estimates of the ages and velocities from matched-resolution observations in the L and C bands. Narrow- and broad-band optical images of some of these sources were made to study their environments and correlate with the symmetry parameters. An extended emission-line region is seen in a quasar, and in four of the objects possible companion galaxies are seen close to the radio axis.

  6. Longwave Imaging for Astronomical Applications, Phase II

    Data.gov (United States)

    National Aeronautics and Space Administration — We propose to develop a compact portable longwave camera for astronomical applications. In Phase 1, we successfully developed the eye of the camera, i.e. the focal...

  7. Astronomers no longer in the dark

    CERN Multimedia

    MacMillan, L

    2002-01-01

    In a significant breakthrough, British and US astronomers have begun to pin down the most elusive material in the universe. They have made a map of dark matter - the heavy, invisible stuff that gives the galaxies their shape (1 page).

  8. Astronomers find distant planet like Jupiter

    CERN Multimedia

    2003-01-01

    Astronomers searching for planetary systems like our solar system have found a planet similar to Jupiter orbiting a nearby star similar to our Sun, about 90 light-years from Earth, according to researchers (1/2 page).

  9. The Soviet center of astronomical data

    International Nuclear Information System (INIS)

    Dluzhnevskaya, O.B.

    1982-01-01

    On the basis of the current French-Soviet cooperation in science and technology, the Astronomical Council of the U.S.S.R. Academy of Sciences and the Strasbourg Center signed in 1977 an agreement on setting up the Soviet Center of Astronomical Data as its filial branch. The Soviet Center was created on the basis of a computation center at the Zvenigorod station of the Astronomical Council of the U.S.S.R. Academy of Sciences, which had already had considerable experience of working with stellar catalogues. In 1979 the Center was equipped with a EC-1033 computer. In 1978-1979 the Soviet Center of Astronomical Data (C.A.D.) received from Strasbourg 96 of the most important catalogues. By September 1981 the list of catalogues available at the Soviet Center has reached 140 catalogues some of which are described. (Auth.)

  10. Giant Radio Jet Coming From Wrong Kind of Galaxy

    Science.gov (United States)

    2003-01-01

    Giant jets of subatomic particles moving at nearly the speed of light have been found coming from thousands of galaxies across the Universe, but always from elliptical galaxies or galaxies in the process of merging -- until now. Using the combined power of the Hubble Space Telescope, the Very Large Array (VLA) and the 8-meter Gemini-South Telescope, astronomers have discovered a huge jet coming from a spiral galaxy similar to our own Milky Way. Radio-optical view of galaxy Combined HST and VLA image of the galaxy 0313-192. Optical HST image shows the galaxy edge-on; VLA image, shown in red, reveals giant jet of speeding particles. For more images, see this link below. CREDIT: Keel, Ledlow & Owen; STScI,NRAO/AUI/NSF, NASA "We've always thought spirals were the wrong kind of galaxy to generate these huge jets, but now we're going to have to re-think some of our ideas on what produces these jets," said William Keel, a University of Alabama astronomer who led the research team. Keel worked with Michael Ledlow of Gemini Observatory and Frazer Owen of the National Radio Astronomy Observatory. The scientists reported their findings at the American Astronomical Society's meeting in Seattle, Washington. "Further study of this galaxy may provide unique insights on just what needs to happen in a galaxy to produce these powerful jets of particles," Keel said. In addition, Owen said, "The loose-knit nature of the cluster of galaxies in which this galaxy resides may play a part in allowing this particular spiral to produce jets." Astronomers believe such jets originate at the cores of galaxies, where supermassive black holes provide the tremendous gravitational energy to accelerate particles to nearly the speed of light. Magnetic fields twisted tightly by spinning disks of material being sucked into the black hole are presumed to narrow the speeding particles into thin jets, like a nozzle on a garden hose. Both elliptical and spiral galaxies are believed to harbor supermassive

  11. Information seeking behavior of Greek astronomers

    OpenAIRE

    Brindesi, Hara; Kapidakis, Sarantos

    2011-01-01

    This study examines three aspects of information seeking behaviour of astronomers in Greece including a) the importance they place in keeping up- to-date with current developments b) the methods they depend on for keeping up-to-date and c) the information sources they mostly use. We adopted an intradisciplinary approach in order to investigate similarities and differences in information seeking behaviour among astronomers when examining them as groups bearing different characteristics, includ...

  12. Basic Optics for the Astronomical Sciences

    CERN Document Server

    Breckinridge, James

    2012-01-01

    This text was written to provide students of astronomy and engineers an understanding of optical science - the study of the generation, propagation, control, and measurement of optical radiation - as it applies to telescopes and instruments for astronomical research in the areas of astrophysics, astrometry, exoplanet characterization, and planetary science. The book provides an overview of the elements of optical design and physical optics within the framework of the needs of the astronomical community.

  13. Latest results of the Tunka Radio Extension

    Directory of Open Access Journals (Sweden)

    Kostunin D.

    2017-01-01

    Full Text Available The Tunka Radio Extension (Tunka-Rex is an antenna array consisting of 63 antennas at the location of the TAIGA facility (Tunka Advanced Instrument for cosmic ray physics and Gamma Astronomy in Eastern Siberia, nearby Lake Baikal. Tunka-Rex is triggered by the air-Cherenkov array Tunka-133 during clear and moonless winter nights and by the scintillator array Tunka-Grande during the remaining time. Tunka-Rex measures the radio emission from the same air-showers as Tunka-133 and Tunka-Grande, but with a higher threshold of about 100 PeV. During the first stages of its operation, Tunka-Rex has proven, that sparse radio arrays can measure air-showers with an energy resolution of better than 15% and the depth of the shower maximum with a resolution of better than 40 g/cm2. To improve and interpret our measurements as well as to study systematic uncertainties due to interaction models, we perform radio simulations with CORSIKA and CoREAS. In this overview we present the setup of Tunka-Rex, discuss the achieved results and the prospects of mass-composition studies with radio arrays.

  14. Astronomers celebrate a year of new Hubble results

    Science.gov (United States)

    1995-02-01

    "We are beginning to understand that because of these observations we are going to have to change the way we look at the Universe," said ESA's Dr Duccio Macchetto, Associate Director for Science Programs at the Space Telescope Science Institute (STScI), Baltimore, Maryland, USA. The European Space Agency plays a major role in the Hubble Space Telescope programme. The Agency provided one of the telescope's four major instruments, called the Faint Object Camera, and two sets of electricity-generating solar arrays. In addition, 15 ESA scientific and technical staff work at the STScI. In return for this contribution, European astronomers are entitled to 15 percent of the telescope's observing time, although currently they account for 20 percent of all observations. "This is a testimony to the quality of the European science community", said Dr Roger Bonnet, Director of Science at ESA. "We are only guaranteed 15 percent of the telescope's use, but consistently receive much more than that." Astronomers from universities, observatories and research institutes across Europe lead more than 60 investigations planned for the telescope's fifth observing cycle, which begins this summer. Many more Europeans contribute to teams led by other astronomers. Looking back to the very start of time European astronomer Dr Peter Jakobsen used ESA's Faint Object Camera to confirm that helium was present in the early Universe. Astronomers had long predicted that 90 percent of the newly born Universe consisted of hydrogen, with helium making up the remainder. Before the refurbished Hubble came along, it was easy to detect the hydrogen, but the primordial helium remained elusive. The ultraviolet capabilities of the telescope, combined with the improvement in spatial resolution following the repair, made it possible for Dr Jakobsen to obtain an image of a quasar close to the edge of the known Universe. A spectral analysis of this picture revealed the quasar's light, which took 13 billion years

  15. Astronomical Polarimetry with the RIT Polarization Imaging Camera

    Science.gov (United States)

    Vorobiev, Dmitry V.; Ninkov, Zoran; Brock, Neal

    2018-06-01

    In the last decade, imaging polarimeters based on micropolarizer arrays have been developed for use in terrestrial remote sensing and metrology applications. Micropolarizer-based sensors are dramatically smaller and more mechanically robust than other polarimeters with similar spectral response and snapshot capability. To determine the suitability of these new polarimeters for astronomical applications, we developed the RIT Polarization Imaging Camera to investigate the performance of these devices, with a special attention to the low signal-to-noise regime. We characterized the device performance in the lab, by determining the relative throughput, efficiency, and orientation of every pixel, as a function of wavelength. Using the resulting pixel response model, we developed demodulation procedures for aperture photometry and imaging polarimetry observing modes. We found that, using the current calibration, RITPIC is capable of detecting polarization signals as small as ∼0.3%. The relative ease of data collection, calibration, and analysis provided by these sensors suggest than they may become an important tool for a number of astronomical targets.

  16. Astronomers debate diamonds in space

    Science.gov (United States)

    1999-04-01

    This is not the first time the intriguing carbonaceous compound has been detected in space. A peculiar elite of twelve stars are known to produce it. The star now added by ISO to this elite is one of the best representatives of this exclusive family, since it emits a very strong signal of the compound. Additionally ISO found a second new member of the group with weaker emission, and also observed with a spectral resolution never achieved before other already known stars in this class. Astronomers think these ISO results will help solve the mystery of the true nature of the compound. Their publication by two different groups, from Spain and Canada, has triggered a debate on the topic, both in astronomy institutes and in chemistry laboratories. At present, mixed teams of astrophysicists and chemists are investigating in the lab compounds whose chemical signature or "fingerprint" matches that detected by ISO. Neither diamonds nor fullerenes have ever been detected in space, but their presence has been predicted. Tiny diamonds of pre-solar origin --older than the Solar System-- have been found in meteorites, which supports the as yet unconfirmed theory of their presence in interstellar space. The fullerene molecule, made of 60 carbon atoms linked to form a sphere (hence the name "buckyball"), has also been extensively searched for in space but never found. If the carbonaceous compound detected by ISO is a fullerene or a diamond, there will be new data on the production of these industrially interesting materials. Fullerenes are being investigated as "capsules" to deliver new pharmaceuticals to the body. Diamonds are commonly used in the electronics industry and for the development of new materials; if they are formed in the dust surrounding some stars, at relatively low temperatures and conditions of low pressure, companies could learn more about the ideal physical conditions to produce them. A textbook case The latest star in which the compound has been found is

  17. The Radio JOVE Project - Shoestring Radio Astronomy

    Science.gov (United States)

    Thieman, J.; Flagg, R.; Greenman, W.; Higgins, C.; Reyes, F.; Sky, J.

    2010-01-01

    Radio JOVE is an education and outreach project intended to give students and other interested individuals hands-on experience in learning radio astronomy. They can do this through building a radio telescope from a relatively inexpensive kit that includes the parts for a receiver and an antenna as well as software for a computer chart recorder emulator (Radio Skypipe) and other reference materials

  18. Space Telecommunications Radio System STRS Cognitive Radio

    Science.gov (United States)

    Briones, Janette C.; Handler, Louis M.

    2013-01-01

    Radios today are evolving from awareness toward cognition. A software defined radio (SDR) provides the most capability for integrating autonomic decision making ability and allows the incremental evolution toward a cognitive radio. This cognitive radio technology will impact NASA space communications in areas such as spectrum utilization, interoperability, network operations, and radio resource management over a wide range of operating conditions. NASAs cognitive radio will build upon the infrastructure being developed by Space Telecommunication Radio System (STRS) SDR technology. This paper explores the feasibility of inserting cognitive capabilities in the NASA STRS architecture and the interfaces between the cognitive engine and the STRS radio. The STRS architecture defines methods that can inform the cognitive engine about the radio environment so that the cognitive engine can learn autonomously from experience, and take appropriate actions to adapt the radio operating characteristics and optimize performance.

  19. Radio-quiet Gamma-ray Pulsars

    Directory of Open Access Journals (Sweden)

    Lupin Chun-Che Lin

    2016-09-01

    Full Text Available A radio-quiet γ-ray pulsar is a neutron star that has significant γ-ray pulsation but without observed radio emission or only limited emission detected by high sensitivity radio surveys. The launch of the Fermi spacecraft in 2008 opened a new epoch to study the population of these pulsars. In the 2nd Fermi Large Area Telescope catalog of γ-ray pulsars, there are 35 (30 % of the 117 pulsars in the catalog known samples classified as radio-quiet γ-ray pulsars with radio flux density (S1400 of less than 30 μJy. Accompanying the observations obtained in various wavelengths, astronomers not only have the opportunity to study the emitting nature of radio-quiet γ-ray pulsars but also have proposed different models to explain their radiation mechanism. This article will review the history of the discovery, the emission properties, and the previous efforts to study pulsars in this population. Some particular cases known as Geminga-like pulsars (e.g., PSR J0633+1746, PSR J0007+7303, PSR J2021+4026, and so on are also to specified discuss their common and specific features.

  20. The radio properties of infrared-faint radio sources

    Science.gov (United States)

    Middelberg, E.; Norris, R. P.; Hales, C. A.; Seymour, N.; Johnston-Hollitt, M.; Huynh, M. T.; Lenc, E.; Mao, M. Y.

    2011-02-01

    Context. Infrared-faint radio sources (IFRS) are objects that have flux densities of several mJy at 1.4 GHz, but that are invisible at 3.6 μm when using sensitive Spitzer observations with μJy sensitivities. Their nature is unclear and difficult to investigate since they are only visible in the radio. Aims: High-resolution radio images and comprehensive spectral coverage can yield constraints on the emission mechanisms of IFRS and can give hints to similarities with known objects. Methods: We imaged a sample of 17 IFRS at 4.8 GHz and 8.6 GHz with the Australia Telescope Compact Array to determine the structures on arcsecond scales. We added radio data from other observing projects and from the literature to obtain broad-band radio spectra. Results: We find that the sources in our sample are either resolved out at the higher frequencies or are compact at resolutions of a few arcsec, which implies that they are smaller than a typical galaxy. The spectra of IFRS are remarkably steep, with a median spectral index of -1.4 and a prominent lack of spectral indices larger than -0.7. We also find that, given the IR non-detections, the ratio of 1.4 GHz flux density to 3.6 μm flux density is very high, and this puts them into the same regime as high-redshift radio galaxies. Conclusions: The evidence that IFRS are predominantly high-redshift sources driven by active galactic nuclei (AGN) is strong, even though not all IFRS may be caused by the same phenomenon. Compared to the rare and painstakingly collected high-redshift radio galaxies, IFRS appear to be much more abundant, but less luminous, AGN-driven galaxies at similar cosmological distances.

  1. Thirteenth Joint European and National Astronomical Meeting

    CERN Document Server

    Iniesta, J C

    2006-01-01

    The book gathers the invited talks to the XIII JENAM conference, organized this time by the European Astronomical Society (EAS) and the Spanish Astronomical Society (SEA), and hosted by the Instituto de Astrofísica de Andalucía (CSIC). All branches of astrophysics are encompassed from the largest scales and cosmology to the solar system and the Sun, through the galaxies and the stars, including a section on astronomical instrumentation. Very relevant experts from all over the world speak in a single book about the most recent, exciting results from their fields in a way which is useful for both researchers in these fields and colleagues working in other disciplines. The book is accompanied by a CD-ROM including the remaining contributions of the meeting in PDF format, hence opening a wide panorama of what is going on in astrophysics nowadays.

  2. Decoding the mechanisms of Antikythera astronomical device

    CERN Document Server

    Lin, Jian-Liang

    2016-01-01

    This book presents a systematic design methodology for decoding the interior structure of the Antikythera mechanism, an astronomical device from ancient Greece. The historical background, surviving evidence and reconstructions of the mechanism are introduced, and the historical development of astronomical achievements and various astronomical instruments are investigated. Pursuing an approach based on the conceptual design of modern mechanisms and bearing in mind the standards of science and technology at the time, all feasible designs of the six lost/incomplete/unclear subsystems are synthesized as illustrated examples, and 48 feasible designs of the complete interior structure are presented. This approach provides not only a logical tool for applying modern mechanical engineering knowledge to the reconstruction of the Antikythera mechanism, but also an innovative research direction for identifying the original structures of the mechanism in the future. In short, the book offers valuable new insights for all...

  3. Astronomers Without Borders: A Global Astronomy Community

    Science.gov (United States)

    Simmons, M.

    2011-10-01

    Astronomers Without Borders (AWB) brings together astronomy enthusiasts of all types - amateur astronomers, educators, professionals and "armchair" astronomers for a variety of online and physicalworld programs. The AWB web site provides social networking and a base for online programs that engage people worldwide in astronomy activities that transcend geopolitical and cultural borders. There is universal interest in astronomy, which has been present in all cultures throughout recorded history. Astronomy is also among the most accessible of sciences with the natural laboratory of the sky being available to people worldwide. There are few other interests for which people widely separated geographically can engage in activities involving the same objects. AWB builds on those advantages to bring people together. AWB also provides a platform where projects can reach a global audience. AWB also provides unique opportunities for multidisciplinary collaboration in EPO programs. Several programs including The World at Night, Global Astronomy Month and others will be described along with lessons learned.

  4. Early results from the Infrared Astronomical Satellite

    International Nuclear Information System (INIS)

    Neugebauer, G.; Beichman, C.A.; Soifer, B.T.

    1984-01-01

    For 10 months the Infrared Astronomical Satellite (IRAS) provided astronomers with what might be termed their first view of the infrared sky on a clear, dark night. Without IRAS, atmospheric absorption and the thermal emission from both the atmosphere and Earthbound telescopes make the task of the infrared astronomer comparable to what an optical astronomer would face if required to work only on cloudy afternoons. IRAS observations are serving astronomers in the same manner as the photographic plates of the Palomar Observatory Sky Survey; just as the optical survey has been used by all astronomers for over three decades, as a source of quantitative information about the sky and as a roadmap for future observations, the results of IRAS will be studied for years to come. IRAS has demonstrated the power of infrared astronomy from space. Already, from a brief look at a miniscule fraction of the data available, we have learned much about the solar system, about nearby stars, about the Galaxy as a whole and about distant extragalactic systems. Comets are much dustier than previously thought. Solid particles, presumably the remnants of the star-formation process, orbit around Vega and other stars and may provide the raw material for planetary systems. Emission from cool interstellar material has been traced throughout the Galaxy all the way to the galactic poles. Both the clumpiness and breadth of the distribution of this material were previously unsuspected. The far-infrared sky away from the galactic plane has been found to be dominate by spiral galaxies, some of which emit more than 50% and as much as 98% of their energy in the infrared - an exciting and surprising revelation. The IRAS mission is clearly the pathfinder for future mission that, to a large extent, will be devoted to the discoveries revealed by IRAS. 8 figures

  5. Observation management challenges of the Square Kilometre Array

    Science.gov (United States)

    Bridger, Alan; Williams, Stewart J.; Nicol, Mark; Klaassen, Pamela; Thompson, Roger S.; Knapic, Cristina; Jerse, Giovanna; Orlati, Andrea; Messina, Marco; Valame, Snehal

    2016-07-01

    The Square Kilometre Array (SKA) will be the world's most advanced radio telescope, designed to explore some of the biggest questions in astronomy today, such as the epoch of re-ionization, the nature of gravity and the origins of cosmic magnetism. SKA1, the first phase of SKA construction, is currently being designed by a large team of experts world-wide. SKA1 comprises two telescopes: a 200-element dish interferometer in South Africa and a 130000-element dipole antenna aperture array in Australia. To enable the ground-breaking science of the SKA an advanced Observation Management system is required to support both the needs of the astronomical community users and the SKA Observatory staff. This system will ensure that the SKA realises its scientiffc aims and achieves optimal scientific throughput. This paper provides an overview of the design of the system that will accept proposals from SKA users, and result in the execution of the scripts that will obtain science data, taking in the stages of detailed preparation, planning and scheduling of the observations and onwards tracking. It describes the unique challenges of the differing requirements of two telescopes, one of which is very much a software telescope, including the need to schedule the data processing as well as the acquisition, and to react to both internally and externally discovered transient events. The scheduling of multiple parallel sub-array use is covered, along with the need to handle commensal observing - using the same data stream to satisfy the science goals of more than one project simultaneously. An international team from academia and industry, drawing on expertise and experience from previous telescope projects, the virtual observatory and comparable problems in industry, has been assembled to design the solution to this challenging but exciting problem.

  6. Coronagraph for astronomical imaging and spectrophotometry

    Science.gov (United States)

    Vilas, Faith; Smith, Bradford A.

    1987-01-01

    A coronagraph designed to minimize scattered light in astronomical observations caused by the structure of the primary mirror, secondary mirror, and secondary support structure of a Cassegrainian telescope is described. Direct (1:1) and reducing (2.7:1) imaging of astronomical fields are possible. High-quality images are produced. The coronagraph can be used with either a two-dimensional charge-coupled device or photographic film camera. The addition of transmission dispersing optics converts the coronagraph into a low-resolution spectrograph. The instrument is modular and portable for transport to different observatories.

  7. A Brief History of Manchester Astronomical Society

    Science.gov (United States)

    Kilburn, K. J.

    Manchester Astronomical Society celebrated its centenary in September 2003. But that centenary was of a hundred years as the MAS: the history of the society goes back much further, and can be traced directly to that great era of.public awareness of astronomy and amateur interest in Victorian England in the last half of the nineteenth century. Allan Chapman has discussed this period in detail, so the present paper concentrates on the MAS's particular influence on Manchester astronomers and recent work on the history of the society.

  8. Novel Algorithms for Astronomical Plate Analyses

    Czech Academy of Sciences Publication Activity Database

    Hudec, René; Hudec, L.

    2011-01-01

    Roč. 32, 1-2 (2011), s. 121-123 ISSN 0250-6335. [Conference on Multiwavelength Variability of Blazars. Guangzhou, 22,09,2010-24,09,2010] R&D Projects: GA ČR GA205/08/1207 Grant - others:GA ČR(CZ) GA102/09/0997; MŠMT(CZ) ME09027 Institutional research plan: CEZ:AV0Z10030501 Keywords : astronomical plates * plate archives archives * astronomical algorithms Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics Impact factor: 0.400, year: 2011

  9. Radio Telescopes to Keep Sharp Eye on Mars Lander

    Science.gov (United States)

    2008-05-01

    Laboratory will get the relayed information," Ghigo added. In Socorro, scientists will collect signals from Phoenix with antennas of the continent-wide Very Long Baseline Array (VLBA), which produces the sharpest images of any astronomical instrument in existence. They will use the VLBA's ability to mark the position of objects in the sky with pinpoint precision to reconstruct the craft's location relative to other spacecraft at Mars to within about 100 feet, despite its great distance from Earth. The VLBA observations will demonstrate NRAO's capability to provide extremely precise measurements of spacecraft positions. This capability may be used to improve the navigational accuracy of future interplanetary missions. NRAO telescopes have contributed to the success of several previous space missions. The VLBA Very Long Baseline Array CREDIT: NRAO/AUI/NSF In 1989, the Very Large Array (VLA) received signals from the Voyager 2 spacecraft as it flew by the distant planet Neptune. The combined collecting area of the 27 VLA antennas and their sensitive receivers made possible a higher data-transmission rate from the spacecraft, thus enabling scientists to obtain more images of Neptune, its rings, and its moons. In 1995, the VLA captured signals from the Galileo spaccraft's probe as the probe dived into the giant planet Jupiter's atmosphere. Like Phoenix, the Galileo probe was designed to send its information to the main spacecraft, which would then relay the signal to Earth. However, the VLA's direct reception of the probe's signal measured the Doppler shift in the signal's frequency and made measurements of Jovian wind speeds 10 times more accurate than they otherwise would have been. In 2005, the GBT and the VLBA snagged the signal from the Huygens probe as it descended into the atmosphere of Saturn's moon Titan. The Doppler measurements of wind speeds made by NRAO and other radio telescopes provided the only wind data from the mission, because of a malfunction in communication

  10. Supporting Evidence for the Astronomically Calibrated Age of Fish Canyon Sanidine

    DEFF Research Database (Denmark)

    Rivera, Tiffany; Storey, Michael; Zeeden, Christian

    The relative nature of the 40Ar/39Ar radio-isotopic dating technique requires that the age and error of the monitor mineral be accurately known. The most widely accepted monitor for Cenozoic geochronology is the Fish Canyon sanidine (FCs), whose recommended published ages have varied by up to 2...... tuned stratigraphic sections. The increasingly robust quality of the astronomical timescale, with precision better than 0.1% for the last 10 million years, suggests this method of intercalibration as the best way to proceed with addressing the true age of FCs. Recently, Kuiper, et al. (2008) determined...... Noblesse multi-collector noble gas mass spectrometer for the 40Ar/39Ar experiments, analyzing single crystals of FCs relative to sanidines from the astronomically dated tephra. The use of the multi-collector instrument allowed us to obtain high precision analyses with a level of precision for fully...

  11. Ram pressure statistics for bent tail radio galaxies

    CSIR Research Space (South Africa)

    Mguda, Z

    2015-01-01

    Full Text Available ), Department of Astronomy, University of Cape Town, Private Bag X3, Rondebosch 7701, South Africa 2South African Astronomical Observatory (SAAO), PO Box 9, 7935 Observatory, Cape Town, South Africa 3Department of Physics, University of Witwatersrand... Published by Oxford University Press on behalf of the Royal Astronomical Society at South A frican A stronom ical O bservatory on D ecem ber 18, 2014 http://m nras.oxfordjournals.org/ D ow nloaded from Statistics for bent radio sources 3311 are left for a...

  12. Multi-channel software defined radio experimental evaluation and analysis

    CSIR Research Space (South Africa)

    Van der Merwe, JR

    2014-09-01

    Full Text Available Multi-channel software-defined radios (SDRs) can be utilised as inexpensive prototyping platforms for transceiver arrays. The application for multi-channel prototyping is discussed and measured results of coherent channels for both receiver...

  13. LOW-FREQUENCY IMAGING OF FIELDS AT HIGH GALACTIC LATITUDE WITH THE MURCHISON WIDEFIELD ARRAY 32 ELEMENT PROTOTYPE

    Energy Technology Data Exchange (ETDEWEB)

    Williams, Christopher L.; Hewitt, Jacqueline N.; Levine, Alan M. [MIT Kavli Institute for Astrophysics and Space Research, Cambridge, MA (United States); De Oliveira-Costa, Angelica; Hernquist, Lars L.; Bernardi, Gianni [Harvard-Smithsonian Center for Astrophysics, Cambridge, MA (United States); Bowman, Judd D. [School of Earth and Space Exploration, Arizona State University, Tempe, AZ (United States); Briggs, Frank H. [Research School of Astronomy and Astrophysics, The Australian National University, Canberra (Australia); Gaensler, B. M.; Mitchell, Daniel A.; Subrahmanyan, Ravi; Sadler, Elaine M. [ARC Centre of Excellence for All-sky Astrophysics (CAASTRO) (Australia); Morales, Miguel F. [Department of Physics, University of Washington, Seattle, WA (United States); Sethi, Shiv K. [Raman Research Institute, Bangalore (India); Arcus, Wayne; Crosse, Brian W. [International Centre for Radio Astronomy Research, Curtin University, Perth (Australia); Barnes, David G. [Center for Astrophysics and Supercomputing, Swinburne University of Technology, Melbourne (Australia); Bunton, John D. [CSIRO Astronomy and Space Science, Epping (Australia); Cappallo, Roger C.; Corey, Brian E., E-mail: clmw@mit.edu [MIT Haystack Observatory, Westford, MA (United States); and others

    2012-08-10

    The Murchison Widefield Array (MWA) is a new low-frequency, wide-field-of-view radio interferometer under development at the Murchison Radio-astronomy Observatory in Western Australia. We have used a 32 element MWA prototype interferometer (MWA-32T) to observe two 50 Degree-Sign diameter fields in the southern sky, covering a total of {approx}2700 deg{sup 2}, in order to evaluate the performance of the MWA-32T, to develop techniques for epoch of reionization experiments, and to make measurements of astronomical foregrounds. We developed a calibration and imaging pipeline for the MWA-32T, and used it to produce {approx}15' angular resolution maps of the two fields in the 110-200 MHz band. We perform a blind source extraction using these confusion-limited images, and detect 655 sources at high significance with an additional 871 lower significance source candidates. We compare these sources with existing low-frequency radio surveys in order to assess the MWA-32T system performance, wide-field analysis algorithms, and catalog quality. Our source catalog is found to agree well with existing low-frequency surveys in these regions of the sky and with statistical distributions of point sources derived from Northern Hemisphere surveys; it represents one of the deepest surveys to date of this sky field in the 110-200 MHz band.

  14. Emerging technology for astronomical optics metrology

    Science.gov (United States)

    Trumper, Isaac; Jannuzi, Buell T.; Kim, Dae Wook

    2018-05-01

    Next generation astronomical optics will enable science discoveries across all fields and impact the way we perceive the Universe in which we live. To build these systems, optical metrology tools have been developed that push the boundary of what is possible. We present a summary of a few key metrology technologies that we believe are critical for the coming generation of optical surfaces.

  15. Cosmological field theory for observational astronomers

    International Nuclear Information System (INIS)

    Zel'Dovich, Y.B.

    1987-01-01

    Theories of the very early Universe that use scalar fields (i.e., the so-called inflationary models of the Universe) have now come into wide use. The inflationary universe approach may perhaps solve some of the most difficult enigmas about the Universe as a whole. The inflationary universe forms a good bridge between the quantum theory of the birth of the Universe (which is still in the initial stages of development) and the standard hot Big Bang theory (which is well established, at least qualitatively). Therefore, an understanding of the basic ideas of inflation is a must for astronomers interested in the broad picture of the science. Astronomers are mathematically oriented enough (via celestial mechanics, electromagnetic theory, magnetohydrodynamics, nuclear reactions,etc.) that there is no negative attitude towards formulae in general. What the astronomer lacks is a knowledge of recent developments in particle physics and field theory. The astronomer should not be blamed for this, because these branches of physics are developing in a very peculiar fashion: some subfields of it are progressing comparatively slowly, with experimental verifications at each and every step, while other subfields progress rapidly

  16. Astronomía en la cultura

    Science.gov (United States)

    López, A.; Giménez Benitez, S.; Fernández, L.

    La Astronomía en la Cultura es el estudio interdisciplinario a nivel global de la astronomía prehistórica, antigua y tradicional, en el marco de su contexto cultural. Esta disciplina abarca cualquier tipo de estudios o líneas de investigación en que se relacione a la astronomía con las ciencias humanas o sociales. En ella se incluyen tanto fuentes escritas, relatos orales como fuentes arqueológicas, abarcando entre otros, los siguientes temas: calendarios, observación práctica, cultos y mitos, representación simbólica de eventos, conceptos y objetos astronómicos, orientación astronómica de tumbas, templos, santuarios y centros urbanos, cosmología tradicional y la aplicación ceremonial de tradiciones astronómicas, la propia historia de la astronomía y la etnoastronomía (Krupp, 1989) (Iwaniszewski, 1994). En nuestro trabajo abordamos la historia y situación actual de esta disciplina, sus métodos y sus relaciones con otras áreas de investigación.

  17. The radio universe

    International Nuclear Information System (INIS)

    Worvill, R.

    1977-01-01

    Elementary description of the development of radioastronomy, radio waves from the sun and planets, the use of radio telescopes and the detection of nebulae, supernova, radio galaxies and quasars is presented. A brief glossary of terms is included. (UK)

  18. The invisible universe the story of radio astronomy

    CERN Document Server

    Verschuur, Gerrit

    2015-01-01

    Hidden from human view, accessible only to sensitive receivers attached to huge radio telescopes, the invisible universe beyond our senses continues to fascinate and intrigue our imaginations. Closer to home, in the Milky Way galaxy, radio astronomers listen patiently to the ticking of pulsars that tell of star death and states of matter of awesome densities. All of this happens out there in the universe hidden from our eyes, even when aided by the Hubble Space Telescope. This is the story of radio astronomy, of how radio waves are generated by stars, supernova, quasars, colliding galaxies and by the very beginnings of the universe itself. The author discusses what radio astronomers are doing in the New Mexico desert, in a remote valley in Puerto Rico, and in the green Pocahontas Valley in West Virginia, as well as dozens of other remote sites around the world. With each of these observatories, the scientists collect and analyze their data, "listening" to the radio signals from space in order to learn what, ...

  19. Sensitivity of Pulsar Timing Arrays

    Science.gov (United States)

    Siemens, Xavier

    2015-08-01

    For the better part of the last decade, the North American Nanohertz Observatory for Gravitational Waves (NANOGrav) has been using the Green Bank and Arecibo radio telescopes to monitor millisecond pulsars. NANOGrav, along with similar international collaborations, the European Pulsar Timing Array and the Parkes Pulsar Timing Array in Australia, form a consortium of consortia: the International Pulsar Timing Array (IPTA). The goal of the IPTA is to directly detect low-frequency gravitational waves which cause small changes to the times of arrival of radio pulses from millisecond pulsars. In this talk I will discuss the work of NANOGrav and the IPTA as well as our sensitivity to gravitational waves from astrophysical sources. I will show that a detection is possible by the end of the decade.

  20. Radio Astronomy at TIFR, some highlights and reminiscences

    Science.gov (United States)

    Swarup, G.

    Radio astronomy research was initiated at TIFR fifty years ago. In this historical article, I firstly trace my initiation in the field of radio astronomy during 1953-55 in the Radio Physics Laboratory of CSIRO in Australia and later during 1956-63 in USA. In September 1961, four radio astronomers working abroad wrote to a number of scientific organizations in India with their desire to start radio astronomy research in India. Soon thereafter Dr. Homi Bhabha, the founder Director of TIFR, approved the formation of a radio astronomy group therein. I joined TIFR in April 1963. During the last 50 years, TIFR has built two of the world's largest radio telescopes, namely the 530m long and 30 m wide parabolic cylinder equatorially mounted on a hill at Ooty in South India during 1960s and the Giant Metrewave Radio Telescope near Pune, consisting of 30 nos. of fully steerable parabolic dishes of 45 m diameters during 1990s. Fifty years of radio astronomy research at TIFR is briefly highlighted here.

  1. The LOFAR pilot surveys for pulsars and fast radio transient

    NARCIS (Netherlands)

    Coenen, T.; van Leeuwen, J.; Hessels, J.W.T.; et al., [Unknown; Alexov, A.; van der Horst, A.; Law, C.; Rowlinson, A.; Swinbank, J.

    2014-01-01

    We have conducted two pilot surveys for radio pulsars and fast transients with the Low-Frequency Array (LOFAR) around 140 MHz and here report on the first low-frequency fast-radio burst limit and the discovery of two new pulsars. The first survey, the LOFAR Pilot Pulsar Survey (LPPS), observed a

  2. The LOFAR pilot surveys for pulsars and fast radio transients

    NARCIS (Netherlands)

    Coenen, T.J.; van Leeuwen, J.; Hessels, J.W.T.; Stappers, B.W.; Kondratiev, V.I.; Alexov, A.; Breton, R.P.; Bilous, A.; Cooper, S.; Falcke, H.; Fallows, R.A.; Gajjar, V.; Griessmeier, J.M.; Hassall, T.E.; Bentum, Marinus Jan

    2014-01-01

    We have conducted two pilot surveys for radio pulsars and fast transients with the Low-Frequency Array (LOFAR) around 140 MHz and here report on the first low-frequency fast-radio burst limit and the discovery of two new pulsars. The first survey, the LOFAR Pilot Pulsar Survey (LPPS), observed a

  3. Fast radio burst tied to distant dwarf galaxy (Image 2)

    National Science Foundation

    2017-06-07

    Full Text Available Radio telescope at Arecibo only localized the fast radio burst to the area inside the two circles in this image, but the Very Large Array was able to pinpoint it as a dwarf galaxy within the square (shown at intersection of cross hairs in enlarged box)

  4. Radio Astronomy on and Around the Moon

    Science.gov (United States)

    Falcke, Heino; Klein Wolt, Mark; Ping, Jinsong; Chen, Linjie

    2018-06-01

    The exploration of remote places on other planets has now become a major goal in current space flight scenarios. On the other hand, astronomers have always sought the most remote and isolated sites to place their observatories and to make their most precise and most breath taking discoveries. Especially for radio astronomy, lunar exploration offers a complete new window to the universe. The polar region and the far-side of the moon are acknowledged as unique locations for a low-frequency radio telescope providing scientific data at wavelengths that cannot be obtained from the Earth nor from single satellites. Scientific areas to be covered range from radio surveys, to solar-system studies, exo-planet detection, and astroparticle physics. The key science area, however, is the detection and measurement of cosmological 21 cm hydrogen emission from the still unexplored dark ages of the universe. Developing a lunar radio facility can happen in steps and may involve small satellites, rover-based radio antennas, of free- flying constellations around the moon. A first such step could be the Netherlands-Chinese Long Wavelength Explorer (NCLE), which is supposed to be launched in 2018 as part of the ChangE’4 mission to the moon-earth L2 point.

  5. The Beginnings of Australian Radio Astronomy

    Science.gov (United States)

    Sullivan, Woodruff T.

    The early stages of Australian radio astronomy, especially the first decade after World War II, are described in detail. These include the transition of the CSIRO Radiophysics Laboratory, under the leadership of Joseph Pawsey and Taffy Bowen, from a wartime laboratory in 1945 to, by 1950, the largest and one of the two most important radio astronomy groups in the world (with the Cavendish Laboratory at Cambridge University). The initial solar investigations are described, including discovery of the hot corona and development of the sea-cliff interferometer. During this same period painstaking `radio star' observations by John Bolton and colleagues led to the first suggested optical identifications of Taurus-A (the Crab Nebula), Centaurus-A (NGC 5128), and Virgo-A (M87). The factors that led to the extraordinary early success of the Radiophysics Laboratory are analyzed in detail, followed by discussion of how the situation changed significantly in the second decade of 1955-1965. Finally, the development of major Australian instruments, from the Parkes Radio Telescope (1961) to the Australia Telescope (1988), is briefly presented. This chapter is a direct reprint of the following research paper: Sullivan, W., 2005. The beginnings of Australian radio astronomy. Journal of Astronomical History and Heritage, 8, 11-32.

  6. New Life for Astronomical Instruments of the Past at the Astronomical Observatory of Taras Shevchenko

    Science.gov (United States)

    Kazantseva, Liliya

    2012-09-01

    Astronomical instruments of the past are certainly valuable artifacts of the history of science and education. Like other collections of scientific equipment, they also demonstrate i) development of scientific and technical ideas, ii) technological features of the historical period, iii) professional features of artists or companies -- manufacturers, and iv) national and local specificity of production. However, astronomical instruments are also devices made for observations of rare phenomena -- solar eclipses, transits of planets of the solar disk, etc. Instruments used to study these rare events were very different for each event, since the science changed quickly between events. The Astronomical Observatory of Kyiv National Taras Shevchenko University has a collection of tools made by leading European and local shops from the early nineteenth century. These include tools for optically observing the first artificial Earth satellites, photography, chronometry, and meteorology. In addition, it has assembled a library of descriptions of astronomical instruments and makers'price-lists. Of particular interest are the large stationary tools that are still active in their pavilions. Almost every instrument has a long interesting history. Museification of astronomical instruments gives them a second life, expanding educational programs and tracing the development of astronomy in general and scientific institution and region in particular. It would be advisable to first create a regional database of these rare astronomical instruments (which is already being done in Ukraine), then a common global database. By combining all the historical information about astronomical instruments with the advantages of the Internet, you can show the full evolution of an astronomical instrument with all its features. Time is relentless, and much is destroyed, badly kept and thrown in the garbage. We need time to protect, capture, and tell about it.

  7. The Impact of Radio Interference on Future Radio Telescopes

    Science.gov (United States)

    Mitchell, Daniel A.; Robertson, Gordon J.; Sault, Robert J.

    While future radio telescopes will require technological advances from the communications industry interference from sources such as satellites and mobile phones is a serious concern. In addition to the fact that the level of interference is growing constantly the increased capabilities of next generation instruments make them more prone to harmful interference. These facilities must have mechanisms to allow operation in a crowded spectrum. In this report some of the factors which may limit the effectiveness of these mechanisms are investigated. Radio astronomy is unique among other observing wavelengths in that the radiation can be fully sampled at a rate which completely specifies the electromagnetic environment. Knowledge of phases and antennae gain factors affords one the opportunity to attempt to mitigate interference from the astronomical data. At present several interference mitigation techniques have been demonstrated to be extremely effective. However the observational scales of the new facilities will push the techniques to their limits. Processes such as signal decorrelation varying antenna gain and instabilities in the primary beam will have a serious effect on some of the algorithms. In addition the sheer volume of data produced will render some techniques computationally and financially impossible.

  8. Ionospheric Caustics in Solar Radio Observations

    Science.gov (United States)

    Koval, A.; Chen, Y.; Stanislavsky, A.

    2016-12-01

    The Earth ionosphere possesses by natural focusing and defocusing effects on radio waves due to presence of variable ionospheric irregularities which could act like convergent and divergent lenses on incident radiation. In particular, the focusing of emission from the Sun was firstly detected on the Nançay Decameter Array dynamic spectra in the 1980s. On time-frequency spectrograms the intensity variations form specific structures different from well-known solar radio bursts and clearly distinguishing on a background of solar radiation. Such structures have been identified as ionospheric caustics (ICs) and considered to be the result of radio waves refraction on medium scale travelling ionospheric disturbances (MSTIDs). Although nowadays the ICs are registered by different radio observatories due to augmentation of low-frequency radio telescopes, the most recent papers devoted to ICs in solar radio records date back to the 1980s. In this study, we revisit the ICs issue with some new results by conducting a statistical analysis of occurrence rate of ICs in solar dynamic spectra in meter-decameter wavelength range for long continuous period (15 years). The seasonal variations in ICs appearance have been found for the first time. Besides, we report the possible solar cycle dependence of ICs emergence. The radio waves propagation in the ionosphere comprising MSTIDs will be considered. The present research renews the subject of ICs in the low-frequency solar radio astronomy after about 35-year letup.

  9. Expanding radio astronomy in Africa

    International Nuclear Information System (INIS)

    Gaylard, M J

    2013-01-01

    The Square Kilometre Array (SKA) Organisation announced in May 2012 that its members had agreed on a dual site solution for the SKA [1]. South Africa's bid for hosting the SKA has caused a ramp up of radio astronomy in Africa. To develop technology towards the SKA, the South African SKA Project (SKA SA) built a protoype radio telescope in 2007, followed in 2010 the seven antenna Karoo Array Telescope (KAT-7). Next is the 64 antenna MeerKAT, which will merge into SKA Phase 1 in Africa. As SKA Phase 2 is intended to add a high resolution capability with baselines out to 3000 km, the SKA SA brought in partner countries in Africa to host outstations. South Africa has been working with the partners to build capacity to operate the SKA and to benefit from it. The SA Department of Science and Technology (DST) developed a proposal to establish radio telescopes in the partner countries to provide hands-on learning and a capability for Very Long Baseline Interferometry (VLBI) research. Redundant 30 m class satellite antennas are being incorporated in this project.

  10. Low Frequency Space Array

    International Nuclear Information System (INIS)

    Dennison, B.; Weiler, K.W.; Johnston, K.J.

    1987-01-01

    The Low Frequency Space Array (LFSA) is a conceptual mission to survey the entire sky and to image individual sources at frequencies between 1.5 and 26 MHz, a frequency range over which the earth's ionosphere transmits poorly or not at all. With high resolution, high sensitivity observations, a new window will be opened in the electromagnetic spectrum for astronomical investigation. Also, extending observations down to such low frequencies will bring astronomy to the fundamental limit below which the galaxy becomes optically thick due to free-free absorption. A number of major scientific goals can be pursued with such a mission, including mapping galactic emission and absorption, studies of individual source spectra in a frequency range where a number of important processes may play a role, high resolution imaging of extended sources, localization of the impulsive emission from Jupiter, and a search for coherent emission processes. 19 references

  11. The statistics of low frequency radio interference at the Murchison Radio-astronomy Observatory

    OpenAIRE

    Sokolowski, Marcin; Wayth, Randall B.; Lewis, Morgan

    2016-01-01

    We characterize the low frequency radio-frequency interference (RFI) environment at the Murchison Radio-astronomy Observatory (MRO), the location selected for the low-frequency component of the Square Kilometre Array. Data were collected from the BIGHORNS instrument, located at the MRO, which records a contiguous bandwidth between 70 and 300 MHz, between November 2014 to March 2015 inclusive. The data were processed to identify RFI, and we describe a series of statistics in both the time and ...

  12. The detectability of radio emission from exoplanets

    Science.gov (United States)

    Lynch, C. R.; Murphy, Tara; Lenc, E.; Kaplan, D. L.

    2018-05-01

    Like the magnetised planets in our Solar System, magnetised exoplanets should emit strongly at radio wavelengths. Radio emission directly traces the planetary magnetic fields and radio detections can place constraints on the physical parameters of these features. Large comparative studies of predicted radio emission characteristics for the known population of exoplanets help to identify what physical parameters could be key for producing bright, observable radio emission. Since the last comparative study, many thousands of exoplanets have been discovered. We report new estimates for the radio flux densities and maximum emission frequencies for the current population of known exoplanets orbiting pre-main sequence and main-sequence stars with spectral types F-M. The set of exoplanets predicted to produce observable radio emission are Hot Jupiters orbiting young stars. The youth of these system predicts strong stellar magnetic fields and/or dense winds, which are key for producing bright, observable radio emission. We use a new all-sky circular polarisation Murchison Widefield Array survey to place sensitive limits on 200 MHz emission from exoplanets, with 3σ values ranging from 4.0 - 45.0 mJy. Using a targeted Giant Metre Wave Radio Telescope observing campaign, we also report a 3σ upper limit of 4.5 mJy on the radio emission from V830 Tau b, the first Hot Jupiter to be discovered orbiting a pre-main sequence star. Our limit is the first to be reported for the low-frequency radio emission from this source.

  13. BEAM-FORMING ERRORS IN MURCHISON WIDEFIELD ARRAY PHASED ARRAY ANTENNAS AND THEIR EFFECTS ON EPOCH OF REIONIZATION SCIENCE

    Energy Technology Data Exchange (ETDEWEB)

    Neben, Abraham R.; Hewitt, Jacqueline N.; Dillon, Joshua S.; Goeke, R.; Morgan, E. [Kavli Institute for Astrophysics and Space Research, Massachusetts Institute of Technology, Cambridge, MA 02139 (United States); Bradley, Richard F. [Dept. of Electrical and Computer Engineering, University of Virginia, Charlottesville, VA, 22904 (United States); Bernardi, G. [Square Kilometre Array South Africa (SKA SA), Cape Town 7405 (South Africa); Bowman, J. D. [School of Earth and Space Exploration, Arizona State University, Tempe, AZ 85287 (United States); Briggs, F. [Research School of Astronomy and Astrophysics, Australian National University, Canberra, ACT 2611 (Australia); Cappallo, R. J.; Corey, B. E.; Lonsdale, C. J.; McWhirter, S. R. [MIT Haystack Observatory, Westford, MA 01886 (United States); Deshpande, A. A. [Raman Research Institute, Bangalore 560080 (India); Greenhill, L. J. [Harvard-Smithsonian Center for Astrophysics, Cambridge, MA 02138 (United States); Hazelton, B. J.; Morales, M. F. [Department of Physics, University of Washington, Seattle, WA 98195 (United States); Johnston-Hollitt, M. [School of Chemical and Physical Sciences, Victoria University of Wellington, Wellington 6140 (New Zealand); Kaplan, D. L. [Department of Physics, University of Wisconsin–Milwaukee, Milwaukee, WI 53201 (United States); Mitchell, D. A. [CSIRO Astronomy and Space Science (CASS), P.O. Box 76, Epping, NSW 1710 (Australia); and others

    2016-03-20

    Accurate antenna beam models are critical for radio observations aiming to isolate the redshifted 21 cm spectral line emission from the Dark Ages and the Epoch of Reionization (EOR) and unlock the scientific potential of 21 cm cosmology. Past work has focused on characterizing mean antenna beam models using either satellite signals or astronomical sources as calibrators, but antenna-to-antenna variation due to imperfect instrumentation has remained unexplored. We characterize this variation for the Murchison Widefield Array (MWA) through laboratory measurements and simulations, finding typical deviations of the order of ±10%–20% near the edges of the main lobe and in the sidelobes. We consider the ramifications of these results for image- and power spectrum-based science. In particular, we simulate visibilities measured by a 100 m baseline and find that using an otherwise perfect foreground model, unmodeled beam-forming errors severely limit foreground subtraction accuracy within the region of Fourier space contaminated by foreground emission (the “wedge”). This region likely contains much of the cosmological signal, and accessing it will require measurement of per-antenna beam patterns. However, unmodeled beam-forming errors do not contaminate the Fourier space region expected to be free of foreground contamination (the “EOR window”), showing that foreground avoidance remains a viable strategy.

  14. Finding Hidden Treasures: Investigations in US Astronomical Plate Archives

    Czech Academy of Sciences Publication Activity Database

    Hudec, René; Hudec, L.

    2013-01-01

    Roč. 53, č. 1 (2013), s. 23-26 ISSN 1210-2709 R&D Projects: GA ČR GA205/08/1207 Institutional support: RVO:67985815 Keywords : astronomical data archives * astronomical photography * astronomical photographic archives Subject RIV: BH - Optics, Masers, Lasers

  15. Young Astronomers' Observe with ESO Telescopes

    Science.gov (United States)

    1995-11-01

    Today, forty 16-18 year old students and their teachers are concluding a one-week, educational `working visit' to the ESO Headquarters in Garching (See ESO Press Release 14/95 of 8 November 1995). They are the winners of the Europe-wide contest `Europe Towards the Stars', organised by ESO with the support of the European Union, under the auspices of the Third European Week for Scientific and Technological Culture. From November 14-20, they have worked with professional ESO astronomers in order to get insight into the methods and principles of modern astronomy and astrophysics, as carried out at one of the world's foremost international centres. This included very successful remote observations with the ESO 3.5-m New Technology Telescope (NTT) and the 1.4-m Coude Auxiliary Telescope (CAT) via a satellite link between the ESO Headquarters and the La Silla observatory in Chile, 12,000 kilometres away. After a general introduction to modern astronomy on the first day of the visit, the participants divided into six teams, according to their interests. Some chose to observe distant galaxies, others prefered to have a closer look on binary stars, and one team decided to investigate a star which is thought to be surrounded by a proto-planetary system. Each team was supported by an experienced ESO astronomer. Then followed the observations at the remote consoles during three nights, the first at the NTT and the following at the CAT. Each team had access to the telescope during half a night. Although the work schedule - exactly as in `real' science - was quite hard, especially during the following data reduction and interpretative phase, all teams managed extremely well and in high spirits. The young astronomers' observations were favoured by excellent atmospheric conditions. At the NTT, the seeing was better than 0.5 arcsecond during several hours, an exceptional value that allows very good images to be obtained. All observations represent solid and interesting science, and

  16. A user interface framework for the Square Kilometre Array: concepts and responsibilities

    Science.gov (United States)

    Marassi, Alessandro; Brajnik, Giorgio; Nicol, Mark; Alberti, Valentina; Le Roux, Gerhard

    2016-07-01

    The Square Kilometre Array (SKA) project is responsible for developing the SKA Observatory, the world's largest radio telescope, with eventually over a square kilometre of collecting area and including a general headquarters as well as two radio telescopes: SKA1-Mid in South Africa and SKA1-Low in Australia. The SKA project consists of a number of subsystems (elements) among which the Telescope Manager (TM) is the one involved in controlling and monitoring the SKA telescopes. The TM element has three primary responsibilities: management of astronomical observations, management of telescope hardware and software subsystems, management of data to support system operations and all stakeholders (operators, maintainers, engineers and science users) in achieving operational, maintenance and engineering goals. Operators, maintainers, engineers and science users will interact with TM via appropriate user interfaces (UI). The TM UI framework envisaged is a complete set of general technical solutions (components, technologies and design information) for implementing a generic computing system (UI platform). Such a system will enable UI components to be instantiated to allow for human interaction via screens, keyboards, mouse and to implement the necessary logic for acquiring or deriving the information needed for interaction. It will provide libraries and specific Application Programming Interfaces (APIs) to implement operator and engineer interactive interfaces. This paper will provide a status update of the TM UI framework, UI platform and UI components design effort, including the technology choices, and discuss key challenges in the TM UI architecture, as well as our approaches to addressing them.

  17. Surveying the skies how astronomers map the universe

    CERN Document Server

    Wynn-Williams, Gareth

    2016-01-01

    Since the time of Galileo, astronomy has been driven by technological innovation. With each major advance has come the opportunity and enthusiasm to survey the sky in a way that was not possible before. It is these surveys of discovery that are the subject of this book. In the first few chapters the author discusses what astronomers learned from visible-light surveys, first with the naked eye, then using telescopes in the seventeenth century, and photography in the nineteenth century. He then moves to the second half of the twentieth century when the skies started to be swept by radio, infrared, ultraviolet, x-ray and gamma ray telescopes, many of which had to be flown in satellites above the Earth’s atmosphere. These surveys led to the discovery of pulsars, quasars, molecular clouds, protostars, bursters, and black holes. He then returns to Earth to describe several currently active large-scale projects that methodically collect images, photometry and spectra that are then stored in vast publicly-accessibl...

  18. TPCs in high-energy astronomical polarimetry

    International Nuclear Information System (INIS)

    Black, J K

    2007-01-01

    High-energy astrophysics has yet to exploit the unique and important information that polarimetry could provide, largely due to the limited sensitivity of previously available polarimeters. In recent years, numerous efforts have been initiated to develop instruments with the sensitivity required for astronomical polarimetry over the 100 eV to 10 GeV band. Time projection chambers (TPCs), with their high-resolution event imaging capability, are an integral part of some of these efforts. After a brief overview of current astronomical polarimeter development efforts, the role of TPCs will be described in more detail. These include TPCs as photoelectric X-ray polarimeters and TPCs as components of polarizationsensitive Compton and pair-production telescopes

  19. Astronomical Photometry Past, Present, and Future

    CERN Document Server

    Milone, Eugene F

    2011-01-01

    This book brings together experts in the field of astronomical photometry to discuss how their subfields provide the precision and accuracy in astronomical energy flux measurements that are needed to permit tests of astrophysical theories. Differential photometers and photometry, improvements in infrared precision, the improvements in precision and accuracy of CCD photometry, the absolute calibration of flux, the development of the Johnson UBVRI photometric system and other passband systems to measure and precisely classify specific types of stars and astrophysical quantities, and the current capabilities of spectrophotometry and polarimetry to provide precise and accurate data, are all discussed in this volume. The discussion of `differential’ or `two-star’ photometers ranges from early experiments in visual photometry through the Harvard and Princeton polarizing photometers to the pioneering work of Walraven and differential photometers designed to minimize effects of atmospheric extinction and to count...

  20. Division B Commission 6: Astronomical Telegrams

    Science.gov (United States)

    Yamaoka, H.; Green, D. W. E.; Samus, N. N.; Aksnes, K.; Gilmore, A. C.; Nakano, S.; Sphar, T.; Tichá, J.; Williams, G. V.

    2016-04-01

    IAU Commission 6 ``Astronomical Telegrams'' had a single business meeting during Honolulu General Assembly of the IAU. It took place on Tuesday, 11 August 2015. The meeting was attended by Hitoshi Yamaoka (President), Daniel Green (Director of the Central Bureau for Astronomical Telegrams, CBAT, via Skype), Steven Chesley (JPL), Paul Chodas (JPL), Alan Gilmore (Canterbury University), Shinjiro Kouzuma (Chukyo University), Paolo Mazzali (Co-Chair of the Supernova Working Group), Elena Pian (Scuola Normale Superiore di Pisa), Marion Schmitz (chair IAU Working Group Designations + NED), David Tholen (University of Hawaii), Jana Ticha (Klet Observatory), Milos Tichy (Klet Observatory), Giovanni Valsecchi (INAF\\slash Italy), Gareth Williams (Minor Planet Center). Apologies: Nikolai Samus (General Catalogue of Variable Stars, GCVS).

  1. Statistical methods for astronomical data analysis

    CERN Document Server

    Chattopadhyay, Asis Kumar

    2014-01-01

    This book introduces “Astrostatistics” as a subject in its own right with rewarding examples, including work by the authors with galaxy and Gamma Ray Burst data to engage the reader. This includes a comprehensive blending of Astrophysics and Statistics. The first chapter’s coverage of preliminary concepts and terminologies for astronomical phenomenon will appeal to both Statistics and Astrophysics readers as helpful context. Statistics concepts covered in the book provide a methodological framework. A unique feature is the inclusion of different possible sources of astronomical data, as well as software packages for converting the raw data into appropriate forms for data analysis. Readers can then use the appropriate statistical packages for their particular data analysis needs. The ideas of statistical inference discussed in the book help readers determine how to apply statistical tests. The authors cover different applications of statistical techniques already developed or specifically introduced for ...

  2. International Astronomical Union Sympoisum No.50

    CERN Document Server

    Westerlund, B

    1973-01-01

    Dr J. Landi Dessy, Director of the Astronomical Observatory, Cordoba, Argentina, invited the International Astronomical Union to hold a Symposium in Cordoba in connection with the celebration of the Centennial of the Cordoba Observatory; the date of foundation is October 24, 1871. He proposed that the Symposium should deal with Spectral Classification and Multicolour Photometry as seven years had elapsed since the Symposium No. 24 in Saltsj6baden, and much development had occurred in the field. The invitation and the proposal were accepted by the IAU, and the Symposium was held in Villa Carlos Paz, near Cordoba, between October 18 and October 24, 1971. It was attended by about 50 scientists representing Argentina, Canada, Chile, Den­ mark, France, Germany, Italy, Mexico, Sweden, Switzerland, U.K., U.S.A., Vatican City State and Venezuela. The Symposium was divided into four sessions: 1. Classification of slit spectra, 2. Classification of objective-prism spectra, 3. Photometric classification, 4. Catalogues ...

  3. Isaac Newton and the astronomical refraction.

    Science.gov (United States)

    Lehn, Waldemar H

    2008-12-01

    In a short interval toward the end of 1694, Isaac Newton developed two mathematical models for the theory of the astronomical refraction and calculated two refraction tables, but did not publish his theory. Much effort has been expended, starting with Biot in 1836, in the attempt to identify the methods and equations that Newton used. In contrast to previous work, a closed form solution is identified for the refraction integral that reproduces the table for his first model (in which density decays linearly with elevation). The parameters of his second model, which includes the exponential variation of pressure in an isothermal atmosphere, have also been identified by reproducing his results. The implication is clear that in each case Newton had derived exactly the correct equations for the astronomical refraction; furthermore, he was the first to do so.

  4. EDUCATIONAL ASTRONOMICAL OBSERVATIONS ON REMOTE ACCESS TELESCOPES

    Directory of Open Access Journals (Sweden)

    Ivan P. Kriachko

    2016-01-01

    Full Text Available The purpose of this article is to show the way of overcoming one of the major problems of astronomy teaching methods in upper secondary school – organization of educational astronomical observations. Nowadays it became possible to perform such observations on remote access telescopes. By using up-to-date informational and communicational technologies, having an opportunity to work with robotic telescopes allows us to organize a unique cognitive and research oriented activities for students while conducting their specialized astronomical studies. Below here is given a brief description of the most significant robotic telescopes and the way of the usage of open remote access telescopic network which was created by professors and scientists of Harvard-Smithsonian Center for Astrophysics, USA.

  5. Recruitment and Retention of LGBTIQ Astronomers

    Science.gov (United States)

    Dixon, William Van Dyke

    2012-01-01

    While lesbian, gay, bisexual, transgender, intersex, or questioning (LGBTIQ) astronomers face many of the same workplace challenges as women and racial/ethnic minorities, from implicit bias to overt discrimination, other challenges are unique to this group. An obvious example is the absence at many institutions of health insurance and other benefits for the same-sex domestic partners of their employees. More subtle is the psychological toll paid by LGBTIQ astronomers who remain "in the closet," self-censoring every statement about their personal lives. Paradoxically, the culture of the physical sciences, in which sexuality, gender identity, and gender expression are considered irrelevant, can discourage their discussion, further isolating LGBTIQ researchers. Addressing these challenges is not just a matter of fairness; it is an essential tool in the recruitment and retention of the brightest researchers and in assuring their productivity. We will discuss these issues and what individuals and departments can to make their institutions more welcoming to their LGBTIQ colleagues.

  6. Astronomía Mocoví

    Science.gov (United States)

    López, A.; Giménez Benitez, S.; Fernández, L.

    El presente trabajo, es una revisión crítica de la astronomía en la cultura Mocoví, aportando a lo realizado previamente por Lehmann Nistche (Lehmann Nistche, 1924 y 1927) el resultado de nuestro trabajo de campo. Un mayor conocimiento de las cosmovisiones de las etnias de esta área es fundamental para una mejor comprensión de la dispersión de las ideas cosmológicas entre los pueblos aborígenes americanos, dada la importancia del corredor chaqueño como conexión entre las altas culturas andinas, la mesopotamia y la región pampeana (Susnik, 1972). Para ello se realiza una comparación con otras cosmovisiones del área americana. Nuestro aporte se enmarca dentro de las actuales líneas de trabajo mundialmente en desarrollo en Astronomía en la Cultura.

  7. The data analysis facilities that astronomers want

    International Nuclear Information System (INIS)

    Disney, M.

    1985-01-01

    This paper discusses the need and importance of data analysis facilities and what astronomers ideally want. A brief survey is presented of what is available now and some of the main deficiencies and problems with today's systems are discussed. The main sources of astronomical data are presented incuding: optical photographic, optical TV/CCD, VLA, optical spectros, imaging x-ray satellite, and satellite planetary camera. Landmark discoveries are listed in a table, some of which include: our galaxy as an island, distance to stars, H-R diagram (stellar structure), size of our galaxy, and missing mass in clusters. The main problems at present are discussed including lack of coordinated effort and central planning, differences in hardware, and measuring performance

  8. Explaining fast radio bursts through Dicke's superradiance

    Science.gov (United States)

    Houde, Martin; Mathews, Abhilash; Rajabi, Fereshteh

    2018-03-01

    Fast radio bursts (FRBs), characterized by strong bursts of radiation intensity at radio wavelengths lasting on the order of a millisecond, have yet to be firmly associated with a family, or families, of astronomical sources. It follows that despite the large number of proposed models, no well-defined physical process has been identified to explain this phenomenon. In this paper, we demonstrate how Dicke's superradiance, for which evidence has recently been found in the interstellar medium, can account for the characteristics associated with FRBs. Our analysis and modelling of previously detected FRBs suggest they could originate from regions in many ways similar to those known to harbour masers or megamasers, and result from the coherent radiation emanating from populations of molecules associated with large-scale entangled quantum mechanical states. We estimate this entanglement to involve as many as ˜1030 to ˜1032 molecules over distances spanning 100-1000 au.

  9. The Repeating Fast Radio Burst FRB 121102 as Seen on Milliarcsecond Angular Scales

    NARCIS (Netherlands)

    Marcote, B.; Paragi, Z.; Hessels, J.W.T.; Keimpema, A.; van Langevelde, H.J.; Huang, Y.; Bassa, C.G.; Bogdanov, S.; Bower, G.C.; Burke-Spolaor, S.; Butler, B.J.; Campbell, R.M.; Chatterjee, S.; Cordes, J.M.; Demorest, P.; Garrett, M.A.; Ghosh, T.; Kaspi, V.M.; Law, C.J.; Lazio, T.J.W.; McLaughlin, M.A.; Ransom, S.M.; Salter, C.J.; Scholz, P.; Seymour, A.; Siemion, A.; Spitler, L.G.; Tendulkar, S.P.; Wharton, R.S.

    2017-01-01

    The millisecond-duration radio flashes known as fast radio bursts (FRBs) represent an enigmatic astrophysical phenomenon. Recently, the sub-arcsecond localization (∼100 mas precision) of FRB 121102 using the Very Large Array has led to its unambiguous association with persistent radio and optical

  10. A website for astronomical news in Spanish

    Science.gov (United States)

    Ortiz-Gil, A.

    2008-06-01

    Noticias del Cosmos is a collection of web pages within the Astronomical Observatory of the University of Valencia's website where we publish short daily summaries of astronomical press releases. Most, if not all of, the releases are originally written in English, and often Spanish readers may find them difficult to understand because not many people are familiar with the scientific language employed in these releases. Noticias del Cosmos has two principal aims. First, we want to communicate the latest astronomical news on a daily basis to a wide Spanish-speaking public who would otherwise not be able to read them because of the language barrier. Second, daily news can be used as a tool to introduce the astronomical topics of the school curriculum in a more immediate and relevant way. Most of the students at school have not yet reached a good enough level in their knowledge of English to fully understand a press release, and Noticias del Cosmos offers them and their teachers this news in their mother tongue. During the regular programme of school visits at the Observatory we use the news as a means of showing that there is still a lot to be discovered. So far the visits to the website have been growing steadily. Between June 2003 and June 2007 we had more than 30,000 visits (excluding 2006). More than 50% of the visits come from Spain, followed by visitors from South and Central America. The feedback we have received from teachers so far has been very positive, showing the usefulness of news items in the classroom when teaching astronomy.

  11. Astronomical random numbers for quantum foundations experiments

    Science.gov (United States)

    Leung, Calvin; Brown, Amy; Nguyen, Hien; Friedman, Andrew S.; Kaiser, David I.; Gallicchio, Jason

    2018-04-01

    Photons from distant astronomical sources can be used as a classical source of randomness to improve fundamental tests of quantum nonlocality, wave-particle duality, and local realism through Bell's inequality and delayed-choice quantum eraser tests inspired by Wheeler's cosmic-scale Mach-Zehnder interferometer gedanken experiment. Such sources of random numbers may also be useful for information-theoretic applications such as key distribution for quantum cryptography. Building on the design of an astronomical random number generator developed for the recent cosmic Bell experiment [Handsteiner et al. Phys. Rev. Lett. 118, 060401 (2017), 10.1103/PhysRevLett.118.060401], in this paper we report on the design and characterization of a device that, with 20-nanosecond latency, outputs a bit based on whether the wavelength of an incoming photon is greater than or less than ≈700 nm. Using the one-meter telescope at the Jet Propulsion Laboratory Table Mountain Observatory, we generated random bits from astronomical photons in both color channels from 50 stars of varying color and magnitude, and from 12 quasars with redshifts up to z =3.9 . With stars, we achieved bit rates of ˜1 ×106Hz/m 2 , limited by saturation of our single-photon detectors, and with quasars of magnitudes between 12.9 and 16, we achieved rates between ˜102 and 2 ×103Hz /m2 . For bright quasars, the resulting bitstreams exhibit sufficiently low amounts of statistical predictability as quantified by the mutual information. In addition, a sufficiently high fraction of bits generated are of true astronomical origin in order to address both the locality and freedom-of-choice loopholes when used to set the measurement settings in a test of the Bell-CHSH inequality.

  12. Astronomy Legacy Project - Pisgah Astronomical Research Institute

    Science.gov (United States)

    Barker, Thurburn; Castelaz, Michael W.; Rottler, Lee; Cline, J. Donald

    2016-01-01

    Pisgah Astronomical Research Institute (PARI) is a not-for-profit public foundation in North Carolina dedicated to providing hands-on educational and research opportunities for a broad cross-section of users in science, technology, engineering and math (STEM) disciplines. In November 2007 a Workshop on a National Plan for Preserving Astronomical Photographic Data (2009ASPC,410,33O, Osborn, W. & Robbins, L) was held at PARI. The result was the establishment of the Astronomical Photographic Data Archive (APDA) at PARI. In late 2013 PARI began ALP (Astronomy Legacy Project). ALP's purpose is to digitize an extensive set of twentieth century photographic astronomical data housed in APDA. Because of the wide range of types of plates, plate dimensions and emulsions found among the 40+ collections, plate digitization will require a versatile set of scanners and digitizing instruments. Internet crowdfunding was used to assist in the purchase of additional digitization equipment that were described at AstroPlate2014 Plate Preservation Workshop (www.astroplate.cz) held in Prague, CZ, March, 2014. Equipment purchased included an Epson Expression 11000XL scanner and two Nikon D800E cameras. These digital instruments will compliment a STScI GAMMA scanner now located in APDA. GAMMA will be adapted to use an electroluminescence light source and a digital camera with a telecentric lens to achieve high-speed high-resolution scanning. The 1μm precision XY stage of GAMMA will allow very precise positioning of the plate stage. Multiple overlapping CCD images of small sections of each plate, tiles, will be combined using a photo-mosaic process similar to one used in Harvard's DASCH project. Implementation of a software pipeline for the creation of a SQL database containing plate images and metadata will be based upon APPLAUSE as described by Tuvikene at AstroPlate2014 (www.astroplate.cz/programs/).

  13. International astronomical remote present observation on IRC.

    Science.gov (United States)

    Ji, Kaifan; Cao, Wenda; Song, Qian

    On March 6 - 7, 1997, an international astronomical remote present observation (RPO) was made on Internet Relay Chat (IRC) for the first time. Seven groups in four countries, China, United States, Canada and Great Britain, used the 1 meter telescope of Yunnan observatory together by the way of remote present observation. Within minutes, images were "On-line" by FTP, and every one was able to get them by anonymous ftp and discuss them on IRC from different widely separated sites.

  14. AstroWeb -- Internet Resources for Astronomers

    Science.gov (United States)

    Jackson, R. E.; Adorf, H.-M.; Egret, D.; Heck, A.; Koekemoer, A.; Murtagh, F.; Wells, D. C.

    AstroWeb is a World Wide Web (WWW) interface to a collection of Internet accessible resources aimed at the astronomical community. The collection currently contains more than 1000 WWW, Gopher, Wide Area Information System (WAIS), Telnet, and Anonymous FTP resources, and it is still growing. AstroWeb provides the additional value-added services: categorization of each resource; descriptive paragraphs for some resources; searchable index of all resource information; 3 times daily search for ``dead'' or ``unreliable'' resources.

  15. The Astronomical Pulse of Global Extinction Events

    Directory of Open Access Journals (Sweden)

    David F.V. Lewis

    2006-01-01

    Full Text Available The linkage between astronomical cycles and the periodicity of mass extinctions is reviewed and discussed. In particular, the apparent 26 million year cycle of global extinctions may be related to the motion of the solar system around the galaxy, especially perpendicular to the galactic plane. The potential relevance of Milankovitch cycles is also explored in the light of current evidence for the possible causes of extinction events over a geological timescale.

  16. Direction of Radio Finding via MUSIC (Multiple Signal Classification) Algorithm for Hardware Design System

    Science.gov (United States)

    Zhang, Zheng

    2017-10-01

    Concept of radio direction finding systems, which use radio direction finding is based on digital signal processing algorithms. Thus, the radio direction finding system becomes capable to locate and track signals by the both. Performance of radio direction finding significantly depends on effectiveness of digital signal processing algorithms. The algorithm uses the Direction of Arrival (DOA) algorithms to estimate the number of incidents plane waves on the antenna array and their angle of incidence. This manuscript investigates implementation of the DOA algorithms (MUSIC) on the uniform linear array in the presence of white noise. The experiment results exhibit that MUSIC algorithm changed well with the radio direction.

  17. Preserving and Archiving Astronomical Photographic Plates

    Science.gov (United States)

    Castelaz, M. W.; Cline, J. D.

    2005-05-01

    Astronomical objects change with time. New observations complement past observations recorded on photographic plates. Analyses of changes provide essential routes to information about an object's formation, constitution and evolution. Preserving a century of photographic plate observations is thus of paramount importance. Plate collections are presently widely dispersed; plates may be stored in poor conditions, and are effectively inaccessible to both researchers and historians. We describe a planned project at Pisgah Astronomical Research Institute to preserve the collections of astronomical plates in the United States by gathering them into a single storage location. Collections will be sorted, cleaned, and cataloged on-line so as to provide access to researchers. Full scientific and historic use of the material then requires the observations themselves to be accessible digitally. The project's goal will be the availability of these data as a unique, fully-maintained scientific and educational resource. The new archive will support trans-disciplinary research such as the chemistry of the Earth's atmosphere, library information science, trends in local weather patterns, and impacts of urbanization on telescope use, while the hand-written observatory logs will be a valuable resource for science historians and biographers.

  18. Elizabeth Brown (1830-1899), solar astronomer

    Science.gov (United States)

    Creese, M.

    1998-08-01

    Were it not for the fact that she was a woman, Elizabeth Brown might well be thought of as a fairly typical nineteenth-century British amateur astronomer. She has a place, although a relatively modest one, in the distinguished group of people who, with their own fortunes, carried out much of the astronomical research being done in the country at a time before extensive government support was forthcoming for the work.1 Her career in fact follows a pattern common to several of the nineteenth-century men astronomers in that her full productive period came only after she was freed from her primary responsibilities; she did not have to amass the necessary financial resources as did many of the men,2 but she had the time-consuming responsibility, not unusual for a Victorian woman, of caring for a parent through a lengthy old age. Only after her father died at the age of ninety-one, did Elizabeth, then in her early fifties, begin her sixteen years of remarkable public activity in astronomy.

  19. AESoP: Astronomical Extinction Spectrophotometer

    Science.gov (United States)

    Linford, Justin; McGraw, J.; Zimmer, P.; Ackermann, M.; Fitch, J.

    2009-01-01

    The Earth's atmosphere is a major obstruction to the precision and accuracy of ground-based photometry. The atmosphere removes light from astronomical objects both by absorption and scattering by constituent molecules, aerosols and clouds. These effects can change significantly over short time periods and over modest angles on the sky. To further understand these effects, the UNM Measurement Astrophysics Group has designed, built and recently deployed the Astronomical Extinction Spectrophotometer (AESoP), a 100mm objective grating spectrometer. By monitoring bright stars in sensibly the same direction as a larger photometric telescope is observing, AESoP will measure the wavelength-dependent extinction due to the Earth's atmosphere from 450nm to 900nm on time scales of approximately one minute. The collocated Astronomical LIDAR for Extinction (ALE) provides a high-precision monochromatic extinction measurement at 527nm. Knowing the extinction at a single wavelength allows us to pin the relative spectra generated by AESoP. These extinction spectra can then be integrated over the bandpass of the photometric telescope system to create real time corrections of observations. We present the design and construction of AESoP along with the preliminary results of our first combined observing campaign. This effort is our first step toward breaking the 1% photometry barrier. This project is funded by AFRL Grant FA9451-04-2-0355

  20. GalileoMobile: Astronomical activities in schools

    Science.gov (United States)

    Dasi Espuig, Maria; Vasquez, Mayte; Kobel, Philippe

    GalileoMobile is an itinerant science education initiative run on a voluntary basis by an international team of astronomers, educators, and science communicators. Our team's main goal is to make astronomy accessible to schools and communities around the globe that have little or no access to outreach actions. We do this by performing teacher workshops, activities with students, and donating educational material. Since the creation of GalileoMobile in 2008, we have travelled to Chile, Bolivia, Peru, India, and Uganda, and worked with 56 schools in total. Our activities are centred on the GalileoMobile Handbook of Activities that comprises around 20 astronomical activities which we adapted from many different sources, and translated into 4 languages. The experience we gained in Chile, Bolivia, Peru, India, and Uganda taught us that (1) bringing experts from other countries was very stimulating for children as they are naturally curious about other cultures and encourages a collaboration beyond borders; (2) high-school students who were already interested in science were always very eager to interact with real astronomers doing research to ask for career advice; (3) inquiry-based methods are important to make the learning process more effective and we have therefore, re-adapted the activities in our Handbook according to these; (4) local teachers and university students involved in our activities have the potential to carry out follow-up activities, and examples are those from Uganda and India.

  1. Astrobiology: An astronomer's perspective

    International Nuclear Information System (INIS)

    Bergin, Edwin A.

    2014-01-01

    In this review we explore aspects of the field of astrobiology from an astronomical viewpoint. We therefore focus on the origin of life in the context of planetary formation, with additional emphasis on tracing the most abundant volatile elements, C, H, O, and N that are used by life on Earth. We first explore the history of life on our planet and outline the current state of our knowledge regarding the delivery of the C, H, O, N elements to the Earth. We then discuss how astronomers track the gaseous and solid molecular carriers of these volatiles throughout the process of star and planet formation. It is now clear that the early stages of star formation fosters the creation of water and simple organic molecules with enrichments of heavy isotopes. These molecules are found as ice coatings on the solid materials that represent microscopic beginnings of terrestrial worlds. Based on the meteoritic and cometary record, the process of planet formation, and the local environment, lead to additional increases in organic complexity. The astronomical connections towards this stage are only now being directly made. Although the exact details are uncertain, it is likely that the birth process of star and planets likely leads to terrestrial worlds being born with abundant water and organics on the surface

  2. Astronomical Virtual Observatories Through International Collaboration

    Directory of Open Access Journals (Sweden)

    Masatoshi Ohishi

    2010-03-01

    Full Text Available Astronomical Virtual Observatories (VOs are emerging research environment for astronomy, and 16 countries and a region have funded to develop their VOs based on international standard protocols for interoperability. The 16 funded VO projects have established the International Virtual Observatory Alliance (http://www.ivoa.net/ to develop the standard interoperable interfaces such as registry (meta data, data access, query languages, output format (VOTable, data model, application interface, and so on. The IVOA members have constructed each VO environment through the IVOA interfaces. National Astronomical Observatory of Japan (NAOJ started its VO project (Japanese Virtual Observatory - JVO in 2002, and developed its VO system. We have succeeded to interoperate the latest JVO system with other VOs in the USA and Europe since December 2004. Observed data by the Subaru telescope, satellite data taken by the JAXA/ISAS, etc. are connected to the JVO system. Successful interoperation of the JVO system with other VOs means that astronomers in the world will be able to utilize top-level data obtained by these telescopes from anywhere in the world at anytime. System design of the JVO system, experiences during our development including problems of current standard protocols defined in the IVOA, and proposals to resolve these problems in the near future are described.

  3. AWOB: A Collaborative Workbench for Astronomers

    Science.gov (United States)

    Kim, J. W.; Lemson, G.; Bulatovic, N.; Makarenko, V.; Vogler, A.; Voges, W.; Yao, Y.; Kiefl, R.; Koychev, S.

    2015-09-01

    We present the Astronomers Workbench (AWOB1), a web-based collaboration and publication platform for a scientific project of any size, developed in collaboration between the Max-Planck institutes of Astrophysics (MPA) and Extra-terrestrial Physics (MPE) and the Max-Planck Digital Library (MPDL). AWOB facilitates the collaboration between geographically distributed astronomers working on a common project throughout its whole scientific life cycle. AWOB does so by making it very easy for scientists to set up and manage a collaborative workspace for individual projects, where data can be uploaded and shared. It supports inviting project collaborators, provides wikis, automated mailing lists, calendars and event notification and has a built in chat facility. It allows the definition and tracking of tasks within projects and supports easy creation of e-publications for the dissemination of data and images and other resources that cannot be added to submitted papers. AWOB extends the project concept to larger scale consortia, within which it is possible to manage working groups and sub-projects. The existing AWOB instance has so far been limited to Max-Planck members and their collaborators, but will be opened to the whole astronomical community. AWOB is an open-source project and its source code is available upon request. We intend to extend AWOB's functionality also to other disciplines, and would greatly appreciate contributions from the community.

  4. Astrobiology: An astronomer's perspective

    Energy Technology Data Exchange (ETDEWEB)

    Bergin, Edwin A. [University of Michigan, Department of Astronomy, 500 Church Street, Ann Arbor, MI 48109 (United States)

    2014-12-08

    In this review we explore aspects of the field of astrobiology from an astronomical viewpoint. We therefore focus on the origin of life in the context of planetary formation, with additional emphasis on tracing the most abundant volatile elements, C, H, O, and N that are used by life on Earth. We first explore the history of life on our planet and outline the current state of our knowledge regarding the delivery of the C, H, O, N elements to the Earth. We then discuss how astronomers track the gaseous and solid molecular carriers of these volatiles throughout the process of star and planet formation. It is now clear that the early stages of star formation fosters the creation of water and simple organic molecules with enrichments of heavy isotopes. These molecules are found as ice coatings on the solid materials that represent microscopic beginnings of terrestrial worlds. Based on the meteoritic and cometary record, the process of planet formation, and the local environment, lead to additional increases in organic complexity. The astronomical connections towards this stage are only now being directly made. Although the exact details are uncertain, it is likely that the birth process of star and planets likely leads to terrestrial worlds being born with abundant water and organics on the surface.

  5. AAS Publishing News: Astronomical Software Citation Workshop

    Science.gov (United States)

    Kohler, Susanna

    2015-07-01

    Do you write code for your research? Use astronomical software? Do you wish there were a better way of citing, sharing, archiving, or discovering software for astronomy research? You're not alone! In April 2015, AAS's publishing team joined other leaders in the astronomical software community in a meeting funded by the Sloan Foundation, with the purpose of discussing these issues and potential solutions. In attendance were representatives from academic astronomy, publishing, libraries, for-profit software sharing platforms, telescope facilities, and grantmaking institutions. The goal of the group was to establish “protocols, policies, and platforms for astronomical software citation, sharing, and archiving,” in the hopes of encouraging a set of normalized standards across the field. The AAS is now collaborating with leaders at GitHub to write grant proposals for a project to develop strategies for software discoverability and citation, in astronomy and beyond. If this topic interests you, you can find more details in this document released by the group after the meeting: http://astronomy-software-index.github.io/2015-workshop/ The group hopes to move this project forward with input and support from the broader community. Please share the above document, discuss it on social media using the hashtag #astroware (so that your conversations can be found!), or send private comments to julie.steffen@aas.org.

  6. Ghostly Glow Reveals a Hidden Class of Long-Wavelength Radio Emitters

    Science.gov (United States)

    2008-10-01

    (Washington, DC. 08)- A team of scientists, including astronomers from the Naval Research Laboratory (NRL), have detected long wavelength radio emission from a colliding, massive galaxy cluster which, surprisingly, is not detected at the shorter wavelengths typically seen in these objects. The discovery implies that existing radio telescopes have missed a large population of these colliding objects. It also provides an important confirmation of the theoretical prediction that colliding galaxy clusters accelerate electrons and other particles to very high energies through the process of turbulent waves. The team revealed their findings in the October 16, 2008 edition of Nature. This new population of objects is most easily detected at long wavelengths. Professor Greg Taylor of the University of New Mexico and scientific director of the Long Wavelength Array (LWA) points out, "This result is just the tip of the iceberg. When an emerging suite of much more powerful low frequency telescopes, including the LWA in New Mexico, turn their views to the cosmos, the sky will 'light up' with hundreds or even thousands of colliding galaxy clusters." NRL has played a key role in promoting the development of this generation of new instruments and is currently involved with the development of the LWA. NRL radio astronomer and LWA Project Scientist Namir Kassim says "Our discovery of a previously hidden class of low frequency cluster-radio sources is particularly important since the study of galaxy clusters was a primary motivation for development of the LWA." The discovery of the emission in the galaxy cluster Abell 521 (or A521 for short) was made using the Giant Metrewave Radiotelescope (GMRT) in India, and its long wavelength nature was confirmed by the National Science Foundation's (NRAO) Very Large Array (VLA) radio telescope in New Mexico. The attached image shows the radio emission at a wavelength of 125cm in red superimposed on a blue image made from data taken by the

  7. Amateur astronomers in support of observing campaigns

    Science.gov (United States)

    Yanamandra-Fisher, P.

    2014-07-01

    The Pro-Am Collaborative Astronomy (PACA) project evolved from the observational campaign of C/2012 S1 or C/ISON. The success of the paradigm shift in scientific research is now implemented in other comet observing campaigns. While PACA identifies a consistent collaborative approach to pro-am collaborations, given the volume of data generated for each campaign, new ways of rapid data analysis, mining access, and storage are needed. Several interesting results emerged from the synergistic inclusion of both social media and amateur astronomers: - the establishment of a network of astronomers and related professionals that can be galvanized into action on short notice to support observing campaigns; - assist in various science investigations pertinent to the campaign; - provide an alert-sounding mechanism should the need arise; - immediate outreach and dissemination of results via our media/blogger members; - provide a forum for discussions between the imagers and modelers to help strategize the observing campaign for maximum benefit. In 2014, two new comet observing campaigns involving pro-am collaborations have been identified: (1) C/2013 A1 (C/Siding Spring) and (2) 67P/Churyumov-Gerasimenko (CG). The evolving need for individual customized observing campaigns has been incorporated into the evolution of PACA (Pro-Am Collaborative Astronomy) portal that currently is focused on comets: from supporting observing campaigns for current comets, legacy data, historical comets; interconnected with social media and a set of shareable documents addressing observational strategies; consistent standards for data; data access, use, and storage, to align with the needs of professional observers. The integration of science, observations by professional and amateur astronomers, and various social media provides a dynamic and evolving collaborative partnership between professional and amateur astronomers. The recent observation of comet 67P, at a magnitude of 21.2, from Siding

  8. Perspectives of intellectual processing of large volumes of astronomical data using neural networks

    Science.gov (United States)

    Gorbunov, A. A.; Isaev, E. A.; Samodurov, V. A.

    2018-01-01

    In the process of astronomical observations vast amounts of data are collected. BSA (Big Scanning Antenna) LPI used in the study of impulse phenomena, daily logs 87.5 GB of data (32 TB per year). This data has important implications for both short-and long-term monitoring of various classes of radio sources (including radio transients of different nature), monitoring the Earth’s ionosphere, the interplanetary and the interstellar plasma, the search and monitoring of different classes of radio sources. In the framework of the studies discovered 83096 individual pulse events (in the interval of the study highlighted July 2012 - October 2013), which may correspond to pulsars, twinkling springs, and a rapid radio transients. Detected impulse events are supposed to be used to filter subsequent observations. The study suggests approach, using the creation of the multilayered artificial neural network, which processes the input raw data and after processing, by the hidden layer, the output layer produces a class of impulsive phenomena.

  9. Observations and Analyses of Heliospheric Faraday Rotation of a Coronal Mass Ejection (CME) Using the LOw Frequency ARray (LOFAR) and Space-Based Imaging Techniques

    Science.gov (United States)

    Bisi, Mario Mark; Jensen, Elizabeth; Sobey, Charlotte; Fallows, Richard; Jackson, Bernard; Barnes, David; Giunta, Alessandra; Hick, Paul; Eftekhari, Tarraneh; Yu, Hsiu-Shan; Odstrcil, Dusan; Tokumaru, Munetoshi; Wood, Brian

    2017-04-01

    Geomagnetic storms of the highest intensity are general driven by coronal mass ejections (CMEs) impacting the Earth's space environment. Their intensity is driven by the speed, density, and, most-importantly, their magnetic-field orientation and magnitude of the incoming solar plasma. The most-significant magnetic-field factor is the North-South component (Bz in Geocentric Solar Magnetic - GSM - coordinates). At present, there are no reliable prediction methods available for this magnetic-field component ahead of the in-situ monitors around the Sun-Earth L1 point. Observations of Faraday rotation (FR) can be used to attempt to determine average magnetic-field orientations in the inner heliosphere. Such a technique has already been well demonstrated through the corona, ionosphere, and also the interstellar medium. Measurements of the polarisation of astronomical (or spacecraft in superior conjunction) radio sources (beacons/radio frequency carriers) through the inner corona of the Sun to obtain the FR have been demonstrated but mostly at relatively-high radio frequencies. Here we show some initial results of true heliospheric FR using the Low Frequency Array (LOFAR) below 200 MHz to investigate the passage of a coronal mass ejection (CME) across the line of sight. LOFAR is a next-generation low-frequency radio interferometer, and a pathfinder to the Square Kilometre Array (SKA) - LOW telescope. We demonstrate preliminary heliospheric FR results through the analysis of observations of pulsar J1022+1001, which commenced on 13 August 2014 at 13:00UT and spanned over 150 minutes in duration. We also show initial comparisons to the FR results via various modelling techniques and additional context information to understand the structure of the inner heliosphere being detected. This observation could indeed pave the way to an experiment which might be implemented for space-weather purposes that will eventually lead to a near-global method for determining the magnetic

  10. Performance of a Highly Sensitive, 19-element, Dual-polarization, Cryogenic L-band Phased-array Feed on the Green Bank Telescope

    Science.gov (United States)

    Roshi, D. Anish; Shillue, W.; Simon, B.; Warnick, K. F.; Jeffs, B.; Pisano, D. J.; Prestage, R.; White, S.; Fisher, J. R.; Morgan, M.; Black, R.; Burnett, M.; Diao, J.; Ruzindana, M.; van Tonder, V.; Hawkins, L.; Marganian, P.; Chamberlin, T.; Ray, J.; Pingel, N. M.; Rajwade, K.; Lorimer, D. R.; Rane, A.; Castro, J.; Groves, W.; Jensen, L.; Nelson, J. D.; Boyd, T.; Beasley, A. J.

    2018-05-01

    A new 1.4 GHz, 19-element, dual-polarization, cryogenic phased-array feed (PAF) radio astronomy receiver has been developed for the Robert C. Byrd Green Bank Telescope (GBT) as part of the Focal L-band Array for the GBT (FLAG) project. Commissioning observations of calibrator radio sources show that this receiver has the lowest reported beam-formed system temperature (T sys) normalized by aperture efficiency (η) of any phased-array receiver to date. The measured T sys/η is 25.4 ± 2.5 K near 1350 MHz for the boresight beam, which is comparable to the performance of the current 1.4 GHz cryogenic single-feed receiver on the GBT. The degradation in T sys/η at ∼4‧ (required for Nyquist sampling) and ∼8‧ offsets from the boresight is, respectively, ∼1% and ∼20% of the boresight value. The survey speed of the PAF with seven formed beams is larger by a factor between 2.1 and 7 compared to a single-beam system, depending on the observing application. The measured performance, both in frequency and offset from the boresight, qualitatively agrees with predictions from a rigorous electromagnetic model of the PAF. The astronomical utility of the receiver is demonstrated by observations of the pulsar B0329+54 and an extended H II region, the Rosette Nebula. The enhanced survey speed with the new PAF receiver will enable the GBT to carry out exciting new science, such as more efficient observations of diffuse, extended neutral hydrogen emission from galactic inflows and searches for fast radio bursts.

  11. Measurement Technique in Radio Frequency Interference (RFI) Study for Radio Astronomy Purposes

    International Nuclear Information System (INIS)

    Roslan Umar; Roslan Umar; Nor Hazmin Sabri; Zainol Abidin Ibrahim; Zamri Zainal Abidin; Asyaari Muhamad

    2015-01-01

    In this paper, we will review our method in making measurements of radio frequency interference (RFI) in order to investigate the sereneness of interference in selected radio interference in Malaysia and Thailand. The selected site are University of Malaya (UM), Universiti Pendidikan Sultan Idris (UPSI), Ubon (UB) and Chiang Mai (CM). The major RFI affecting radio astronomical windows below 1 GHz are electronic equipment system specifically radio navigation between 73.1 MHz and 75.2 MHz, radio broadcasting (151 MHz, 151.8 MHz and 152 MHz), aeronautical navigation (245.5 MHz, 248.7 MHz and 249 MHz and also fixed mobile at 605 MHz, 608.3 MHz, 612.2 MHz, 613.3 MHz. It is obviously showed that all sites within this region are free from interference between 320MHz and 330 MHz and is the best specific region to be considered for solar burst monitoring. We also investigate the effect of RFI on discovery of solar burst. (author)

  12. Radio Telescopes Extend Astronomy's Best "Yardstick," Provide Vital Tool for Unraveling Dark Energy Mystery

    Science.gov (United States)

    2009-06-01

    Radio astronomers have directly measured the distance to a faraway galaxy, providing a valuable "yardstick" for calibrating large astronomical distances and demonstrating a vital method that could help determine the elusive nature of the mysterious Dark Energy that pervades the Universe. Galaxy UGC 3789 Visible-light image of UGC 3789 CREDIT: STScI "We measured a direct, geometric distance to the galaxy, independent of the complications and assumptions inherent in other techniques. The measurement highlights a valuable method that can be used to determine the local expansion rate of the Universe, which is essential in our quest to find the nature of Dark Energy," said James Braatz, of the National Radio Astronomy Observatory (NRAO), who presented the work to the American Astronomical Society's meeting in Pasadena, California. Braatz and his colleagues used the National Science Foundation's Very Long Baseline Array (VLBA) and Robert C. Byrd Green Bank Telescope (GBT), and the Effelsberg Radio Telescope of the Max Planck Institute for Radioastronomy (MPIfR) in Germany to determine that a galaxy dubbed UGC 3789 is 160 million light-years from Earth. To do this, they precisely measured both the linear and angular size of a disk of material orbiting the galaxy's central black hole. Water molecules in the disk act as masers to amplify, or strengthen, radio waves the way lasers amplify light waves. The observation is a key element of a major effort to measure the expansion rate of the Universe, known as the Hubble Constant, with greatly improved precision. That effort, cosmologists say, is the best way to narrow down possible explanations for the nature of Dark Energy. "The new measurement is important because it demonstrates a one-step, geometric technique for measuring distances to galaxies far enough to infer the expansion rate of the Universe," said Braatz. The GBT Robert C. Byrd Green Bank Telescope CREDIT: NRAO/AUI/NSF The VLBA Very Long Baseline Array CREDIT: NRAO

  13. Archiving of interferometric radio and mm/submm data at the National Radio Astronomy Observatory

    Science.gov (United States)

    Lacy, Mark

    2018-06-01

    Modern radio interferometers such as ALMA and the VLA are capable of producing ~1TB/day of data for processing into image products of comparable size. Besides the shear volume of data, the products themselves can be complicated and are sometimes hard to map into standard astronomical archive metadata. We also face similar issues to those faced by archives at other wavelengths, namely the role of archives as the basis of reprocessing platforms and facilities, and the validation and ingestion of user-derived products. In this talk I shall discuss the plans of NRAO in these areas over the next decade.

  14. Interferometry and synthesis in radio astronomy

    CERN Document Server

    Thompson, A Richard; Swenson Jr , George W

    2017-01-01

    This book is open access under a CC BY-NC 4.0 license. The third edition of this indispensable book in radio interferometry provides extensive updates to the second edition, including results and technical advances from the past decade; discussion of arrays that now span the full range of the radio part of the electromagnetic spectrum observable from the ground, 10 MHz to 1 THz; an analysis of factors that affect array speed; and an expanded discussion of digital signal-processing techniques and of scintillation phenomena and the effects of atmospheric water vapor on image distortion, among many other topics. With its comprehensiveness and detailed exposition of all aspects of the theory and practice of radio interferometry and synthesis imaging, this book has established itself as a standard reference in the field. It begins with an overview of the basic principles of radio astronomy, a short history of the development of radio interferometry, and an elementary discussion of the operation of an interferomete...

  15. Radio emission from embryonic superluminous supernova remnants

    Science.gov (United States)

    Omand, Conor M. B.; Kashiyama, Kazumi; Murase, Kohta

    2018-02-01

    It has been widely argued that Type-I superluminous supernovae (SLSNe-I) are driven by powerful central engines with a long-lasting energy injection after the core-collapse of massive progenitors. One of the popular hypotheses is that the hidden engines are fast-rotating pulsars with a magnetic field of B ˜ 1013-1015 G. Murase, Kashiyama & Mészáros proposed that quasi-steady radio/submm emission from non-thermal electron-positron pairs in nascent pulsar wind nebulae can be used as a relevant counterpart of such pulsar-driven supernovae (SNe). In this work, focusing on the nascent SLSN-I remnants, we examine constraints that can be placed by radio emission. We show that the Atacama Large Millimeter/submillimetre Array can detect the radio nebula from SNe at DL ˜ 1 Gpc in a few years after the explosion, while the Jansky Very Large Array can also detect the counterpart in a few decades. The proposed radio follow-up observation could solve the parameter degeneracy in the pulsar-driven SN model for optical/UV light curves, and could also give us clues to young neutron star scenarios for SLSNe-I and fast radio bursts.

  16. Airborne electronically steerable phased array

    Science.gov (United States)

    1972-01-01

    The results are presented of the second stage of a program for the design and development of a phased array capable of simultaneous and separate transmission and reception of radio frequency signals at S-band frequencies. The design goals of this stage were the development of three major areas of interest required for the final prototype model. These areas are the construction and testing of the low-weight, full-scale 128-element array of antenna elements, the development of the RF manifold feed system, and the construction and testing of a working module containing diplexer and transmit and receive circuits.

  17. POLYCOMP: Efficient and configurable compression of astronomical timelines

    Science.gov (United States)

    Tomasi, M.

    2016-07-01

    This paper describes the implementation of polycomp, a open-sourced, publicly available program for compressing one-dimensional data series in tabular format. The program is particularly suited for compressing smooth, noiseless streams of data like pointing information, as one of the algorithms it implements applies a combination of least squares polynomial fitting and discrete Chebyshev transforms that is able to achieve a compression ratio Cr up to ≈ 40 in the examples discussed in this work. This performance comes at the expense of a loss of information, whose upper bound is configured by the user. I show two areas in which the usage of polycomp is interesting. In the first example, I compress the ephemeris table of an astronomical object (Ganymede), obtaining Cr ≈ 20, with a compression error on the x , y , z coordinates smaller than 1 m. In the second example, I compress the publicly available timelines recorded by the Low Frequency Instrument (LFI), an array of microwave radiometers onboard the ESA Planck spacecraft. The compression reduces the needed storage from ∼ 6.5 TB to ≈ 0.75 TB (Cr ≈ 9), thus making them small enough to be kept in a portable hard drive.

  18. The Selection and Protection of Optical Astronomical Observing Sites in China

    Science.gov (United States)

    Wenjing, Jin; Bai, Jinming; Yao, Yongqiang

    2015-03-01

    Before 1950 there are two observatories, Shanghai and Purple Mountain Astronomical Observatories (SHAO and PMO), and two observing stations, Qingdao and Kunming stations in China. With the requirements of astronomical research, two observatories, Beijing and Shaanxi Astronomical Observatories (BAO and SXAO) and two artificial satellite stations, Urumqi and Changchun, were established about 1960. Based on the current management, now there are 4 observatories, SHAO, PMO, NAOC(National Astronomical Observatories), which was grouped from BAO, YNAO and 2 others, as well as XAO (Xinjiang Astronomical Observatory). The optical 1-2 m class telescopes are being operated at former four observatories. SXAO is changed as National Time Service Center. Because of city expansion as well as the traveling and economic developments, these observatories are suffered severe light pollution. For example, Zo Ce is located at the suburb of Shanghai city. A 40 cm double astrograph was installed in 1900 and a 1.56 m optical reflector have been operated since November 1987. In 1994 the seeing is better than 1 and the night sky brightness in V is about 19 mag/arcsec 2, stars fainter than 20 mag with CCD are visibles. In 2007 a large playground was built in Zô Cè area. The light pollution is severe gradually. The night sky brightness has been increased to 15.8 mag/arcsec 2. The other observatories have similar situation. New site surveys and found new stations to solve the problem. Except the solar and radio stations of each Astronomical Observatory, now there are 3 optical observing sites at PMO (Hong-He, Xu-Yi and Yaoan), 2 at SHAO (Zô Cè and Tian Huang Ping) and 2 at YNAO (Kunming and Gao-Mei-Gu) as well as 1 optical observing site at BAO (Xing-Long). The best observing site is Gao-Mei-Gu, which is selected as the optical observing site of YNAO and where atmospheric turbulence distribution is 0.11 near ground with heights from 6.5m to 2.7m during night. Sky brightness in B and V band

  19. Algorithms for classification of astronomical object spectra

    Science.gov (United States)

    Wasiewicz, P.; Szuppe, J.; Hryniewicz, K.

    2015-09-01

    Obtaining interesting celestial objects from tens of thousands or even millions of recorded optical-ultraviolet spectra depends not only on the data quality but also on the accuracy of spectra decomposition. Additionally rapidly growing data volumes demands higher computing power and/or more efficient algorithms implementations. In this paper we speed up the process of substracting iron transitions and fitting Gaussian functions to emission peaks utilising C++ and OpenCL methods together with the NOSQL database. In this paper we implemented typical astronomical methods of detecting peaks in comparison to our previous hybrid methods implemented with CUDA.

  20. Far-infrared spectrophotometer for astronomical observations

    Science.gov (United States)

    Moseley, H.; Silverberg, R. F.

    1981-01-01

    A liquid-helium-cooled far infrared spectrophotometer was built and used to make low resolution observations of the continua of several kinds of astronomical objects using the Kuiper Airborne Observatory. This instrument fills a gap in both sensitivity to continuum sources and spectral resolution between the broadband photometers with lambda/Delta lambda approximately 1 and spectrometers with lambda/Delta lambda greater than 50. While designed primarily to study planetary nebulae, the instrument permits study of the shape of the continua of many weak sources which cannot easily be observed with high resolution systems.

  1. Penn State astronomical image processing system

    International Nuclear Information System (INIS)

    Truax, R.J.; Nousek, J.A.; Feigelson, E.D.; Lonsdale, C.J.

    1987-01-01

    The needs of modern astronomy for image processing set demanding standards in simultaneously requiring fast computation speed, high-quality graphic display, large data storage, and interactive response. An innovative image processing system was designed, integrated, and used; it is based on a supermicro architecture which is tailored specifically for astronomy, which provides a highly cost-effective alternative to the traditional minicomputer installation. The paper describes the design rationale, equipment selection, and software developed to allow other astronomers with similar needs to benefit from the present experience. 9 references

  2. An infrared upconverter for astronomical imaging

    Science.gov (United States)

    Boyd, R. W.; Townes, C. H.

    1977-01-01

    An imaging upconverter has been constructed which is suitable for use in the study of the thermal 10-micron radiation from astronomical sources. The infrared radiation is converted to visible radiation by mixing in a 1-cm-long proustite crystal. The phase-matched 2-kayser bandpass is tunable from 9 to 11 microns. The conversion efficiency is 2 by 10 to the -7th power and the field of view of 40 arc seconds on the sky contains several hundred picture elements, approximately diffraction-limited resolution in a large telescope. The instrument has been used in studies of the sun, moon, Mercury, and VY Canis Majoris.

  3. Le Verrier magnificent and detestable astronomer

    CERN Document Server

    Lequeux, James

    2013-01-01

    Le Verrier was a superb scientist. His discovery of Neptune in 1846 made him the most famous astronomer of his time. He produced a complete theory of the motions of the planets which served as a basis for planetary ephemeris for a full century. Doing this, he discovered an anomaly in the motion of Mercury which later became the first proof of General Relativity. He also founded European meteorology. However his arrogance and bad temper created many enemies, and he was even fired from his position of Director of the Paris Observatory.

  4. The astronomical revolution Copernicus, Kepler, Borelli

    CERN Document Server

    Koyre, Alexandre

    2013-01-01

    Originally published in English in 1973. This volume traces the development of the revolution which so drastically altered man's view of the universe in the sixteenth and seventeenth centuries. The ""astronomical revolution"" was accomplished in three stages, each linked with the work of one man. With Copernicus, the sun became the centre of the universe. With Kepler, celestial dynamics replaced the kinematics of circles and spheres used by Copernicus. With Borelli the unification of celestial and terrestrial physics was completed by abandonment of the circle in favour the straight line to inf

  5. Astronomical Plate Archives and Binary Blazars Studies

    Czech Academy of Sciences Publication Activity Database

    Hudec, René

    2011-01-01

    Roč. 32, 1-2 (2011), s. 91-95 ISSN 0250-6335. [Conference on Multiwavelength Variability of Blazars. Guangzhou, 22,09,2010-24,09,2010] R&D Projects: GA ČR GA205/08/1207 Grant - others:GA ČR(CZ) GA102/09/0997; MŠMT(CZ) ME09027 Institutional research plan: CEZ:AV0Z10030501 Keywords : astronomical plates * plate archives archives * binary blazars Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics Impact factor: 0.400, year: 2011

  6. Array capabilities and future arrays

    International Nuclear Information System (INIS)

    Radford, D.

    1993-01-01

    Early results from the new third-generation instruments GAMMASPHERE and EUROGAM are confirming the expectation that such arrays will have a revolutionary effect on the field of high-spin nuclear structure. When completed, GAMMASHPERE will have a resolving power am order of magnitude greater that of the best second-generation arrays. When combined with other instruments such as particle-detector arrays and fragment mass analysers, the capabilites of the arrays for the study of more exotic nuclei will be further enhanced. In order to better understand the limitations of these instruments, and to design improved future detector systems, it is important to have some intelligible and reliable calculation for the relative resolving power of different instrument designs. The derivation of such a figure of merit will be briefly presented, and the relative sensitivities of arrays currently proposed or under construction presented. The design of TRIGAM, a new third-generation array proposed for Chalk River, will also be discussed. It is instructive to consider how far arrays of Compton-suppressed Ge detectors could be taken. For example, it will be shown that an idealised open-quote perfectclose quotes third-generation array of 1000 detectors has a sensitivity an order of magnitude higher again than that of GAMMASPHERE. Less conventional options for new arrays will also be explored

  7. Baseline-dependent averaging in radio interferometry

    Science.gov (United States)

    Wijnholds, S. J.; Willis, A. G.; Salvini, S.

    2018-05-01

    This paper presents a detailed analysis of the applicability and benefits of baseline-dependent averaging (BDA) in modern radio interferometers and in particular the Square Kilometre Array. We demonstrate that BDA does not affect the information content of the data other than a well-defined decorrelation loss for which closed form expressions are readily available. We verify these theoretical findings using simulations. We therefore conclude that BDA can be used reliably in modern radio interferometry allowing a reduction of visibility data volume (and hence processing costs for handling visibility data) by more than 80 per cent.

  8. Radio morphing - towards a full parametrisation of the radio signal from air showers

    Science.gov (United States)

    Zilles, A.; Charrier, D.; Kotera, K.; Le Coz, S.; Martineau-Huynh, O.; Medina, C.; Niess, V.; Tueros, M.; de Vries, K.

    2017-12-01

    Over the last decades, radio detection of air showers has been established as a detection technique for ultra-high-energy cosmic-rays impinging on the Earth's atmosphere with energies far beyond LHC energies. Today’s second-generation of digital radio-detection experiments, as e.g. AERA or LOFAR, are becoming competitive in comparison to already standard techniques e.g. fluorescence light detection. Thanks to a detailed understanding of the physics of the radio emission in extensive air showers, simulations of the radio signal are already successfully tested and applied in the reconstruction of cosmic rays. However the limits of the computational power resources are easily reached when it comes to computing electric fields at the numerous positions requested by large or dense antenna arrays. In the case of mountainous areas as e.g. for the GRAND array, where 3D shower simulations are necessary, the problem arises with even stronger acuity. Therefore we developed a full parametrisation of the emitted radio signal on the basis of generic shower simulations which will reduce the simulation time by orders of magnitudes. In this talk we will present this concept after a short introduction to the concept of the radio detection of air-shower induced by cosmic rays.

  9. Care of astronomical telescopes and accessories a manual for the astronomical observer and amateur telescope maker

    CERN Document Server

    Pepin, M Barlow

    2005-01-01

    Commercially-made astronomical telescopes are better and less expensive than ever before, and their optical and mechanical performance can be superb. When a good-quality telescope fails to perform as well as it might, the reason is quite probably that it needs a little care and attention! Here is a complete guide for anyone who wants to understand more than just the basics of astronomical telescopes and accessories, and how to maintain them in the peak of condition. The latest on safely adjusting, cleaning, and maintaining your equipment is combined with thoroughly updated methods from the old masters. Here, too, are details of choosing new and used optics and accessories, along with enhancements you can make to extend their versatility and useful lifetime. This book is for you. Really. Looking after an astronomical telescope isn't only for the experts - although there are some things that only an expert should attempt - and every serious amateur astronomer will find invaluable information here, gleaned from ...

  10. 150th Anniversary of the Astronomical Observatory Library of Sciences

    Science.gov (United States)

    Solntseva, T.

    The scientific library of the Astronomical observatory of Kyiv Taras Shevchenko University is one of the oldest ones of such a type in Ukraine. Our Astronomical Observatory and its scientific library will celebrate 150th anniversary of their foundation. 900 volumes of duplicates of Olbers' private library underlay our library. These ones were acquired by Russian Academy of Sciences for Poulkovo observatory in 1841 but according to Struve's order were transmitted to Kyiv Saint Volodymyr University. These books are of great value. There are works edited during Copernicus', Kepler's, Galilei's, Newton's, Descartes' lifetime. Our library contains more than 100000 units of storage - monographs, periodical astronomical editions from the first (Astronomische Nachrichten, Astronomical journal, Monthly Notices etc.), editions of the majority of the astronomical observatories and institutions of the world, unique astronomical atlases and maps

  11. Impact of cognitive radio on radio astronomy

    NARCIS (Netherlands)

    Bentum, Marinus Jan; Boonstra, A.J.; Baan, W.A.

    2010-01-01

    The introduction of new communication techniques requires an increase in the efficiency of spectrum usage. Cognitive radio is one of the new techniques that fosters spectrum efficiency by using unoccupied frequency spectrum for communications. However, cognitive radio will increase the transmission

  12. Fast Radio Bursts

    Indian Academy of Sciences (India)

    Akshaya Rane

    2017-09-12

    ) which were first discovered a decade ago. Following an introduction to radio transients in general, including pulsars and rotating radio transients, we discuss the discovery of FRBs. We then discuss FRB follow-up ...

  13. The Frontiers of the Astronomical Universe

    Science.gov (United States)

    Pecker, Jean-Claude

    1977-01-01

    Reviews the current state of knowledge obtained by means of observations using the increasingly powerful or proficient instruments of astrophysics, radio astronomy, and space astronomy by satellite. In conclusion, he refers to certain mathematical entities introduced into the theory of the origins and evolution of the cosmos. (Author/MA)

  14. Astronomical Alignments in a Neolithic Chinese Site?

    Science.gov (United States)

    Nelson, S.; Stencel, R. E.

    1997-12-01

    In the Manchurian province of Liaoning, near 41N19' and 119E30', exist ruins of a middle Neolithic society (2500 to 4000 BC) known as the Hongshan culture. This location, called Niuheliang, is comprised of 16 locations with monumental structures scattered over 80 square kilometers of hills. Most are stone burial structures that contain jade artifacts implying wealth and power. One structure is unique in being unusually shaped and containing oversized effigies of goddess figures. This structure also has a commanding view of the surrounding landscape. The presence of decorated pottery, jade and worked copper suggests the Hongshan people were sophisticated artisans and engaged in long-distance trading. During 1997, we've conducted a course at Denver as part of our Core Curriculum program for upper division students, that has examined the astronomical and cultural aspects of the Niuheliang site, to attempt to determine whether these contemporaries of the builders of Stonehenge may have included astronomical alignments into their constructions. The preliminary result of our studies suggests that certain monuments have potential for lunar standstill observation from the "goddess temple". For updates on these results, please see our website: www.du.edu/ rstencel/core2103.html.

  15. Sketching the moon an astronomical artist's guide

    CERN Document Server

    Handy, Richard; McCague, Thomas; Rix, Erika; Russell, Sally

    2012-01-01

    Soon after you begin studying the sky through your small telescope or binoculars, you will probably be encouraged by others to make sketches of what you see. Sketching is a time-honored tradition in amateur astronomy and dates back to the earliest times, when telescopes were invented. Even though we have lots of new imaging technologies nowadays, including astrophotography, most observers still use sketching to keep a record of what they see, make them better observers, and in hopes of perhaps contributing something to the body of scientific knowledge about the Moon. Some even sketch because it satisfies their artistic side. The Moon presents some unique challenges to the astronomer-artist, the Moon being so fond of tricks of the light. Sketching the Moon: An Astronomical Artist’s Guide, by five of the best lunar observer-artists working today, will guide you along your way and help you to achieve really high-quality sketches. All the major types of lunar features are covered, with a variety of sketching te...

  16. La radio digital

    Directory of Open Access Journals (Sweden)

    Carlos Eduardo Cortés S.

    2015-01-01

    Full Text Available La radio digital es un producto de la llamada convergencia digital. Las nuevas tecnologías interconectadas permiten la aparición de nuevos modos de audiencia y la implementación de herramientas versátiles. Habla del problema de los estándares, de la radio satelital, la radio digital terrestre, las radios internacionales, la interactividad.

  17. New astronomical references in two Catalonian late medieval documents.

    Science.gov (United States)

    Martínez, María José; Marco, Francisco J

    2014-01-01

    In 2008, after 13 years of preparation, the Generalitat of Catalunya finished the publication of the 10 volumes of the Dietaris de la Generalitat de Catalunya. The Dietaris, as well as a closely related source, the llibre de Jornades 1411/1484 de Jaume Safont, cover the period of 1411 to 1539. In this article, we examine astronomical references contained in these two sources, and place them in their historical context. Our main focus lies on astronomical phenomena that have not previously been published in the astronomical literature. In fact, relatively few astronomical records are accessible in Spanish medieval and early modern history, and our paper intends to fill this gap partially.

  18. The First Astronomical Observatory in Cluj-Napoca

    Science.gov (United States)

    Szenkovits, Ferenc

    2008-09-01

    One of the most important cities of Romania is Cluj-Napoca (Kolozsvár, Klausenburg). This is a traditional center of education, with many universities and high schools. From the second half of the 18th century the University of Cluj has its own Astronomical Observatory, serving for didactical activities and scientific researches. The famous astronomer Maximillian Hell was one of those Jesuits who put the base of this Astronomical Observatory. Our purpose is to offer a short history of the beginnings of this Astronomical Observatory.

  19. Commercial Radio as Communication.

    Science.gov (United States)

    Rothenbuhler, Eric W.

    1996-01-01

    Compares the day-to-day work routines of commercial radio with the principles of a theoretical communication model. Illuminates peculiarities of the conduct of communication by commercial radio. Discusses the application of theoretical models to the evaluation of practicing institutions. Offers assessments of commercial radio deriving from…

  20. SNP Arrays

    Directory of Open Access Journals (Sweden)

    Jari Louhelainen

    2016-10-01

    Full Text Available The papers published in this Special Issue “SNP arrays” (Single Nucleotide Polymorphism Arrays focus on several perspectives associated with arrays of this type. The range of papers vary from a case report to reviews, thereby targeting wider audiences working in this field. The research focus of SNP arrays is often human cancers but this Issue expands that focus to include areas such as rare conditions, animal breeding and bioinformatics tools. Given the limited scope, the spectrum of papers is nothing short of remarkable and even from a technical point of view these papers will contribute to the field at a general level. Three of the papers published in this Special Issue focus on the use of various SNP array approaches in the analysis of three different cancer types. Two of the papers concentrate on two very different rare conditions, applying the SNP arrays slightly differently. Finally, two other papers evaluate the use of the SNP arrays in the context of genetic analysis of livestock. The findings reported in these papers help to close gaps in the current literature and also to give guidelines for future applications of SNP arrays.

  1. Radio Source Morphology: 'nature or nuture'?

    Science.gov (United States)

    Banfield, Julie; Emonts, Bjorn; O'Sullivan, Shane

    2012-10-01

    Radio sources, emanating from supermassive black-holes in the centres of active galaxies, display a large variety of morphological properties. It is a long-standing debate to what extent the differences between various types of radio sources are due to intrinsic properties of the central engine (`nature') or due to the properties of the interstellar medium that surrounds the central engine and host galaxy (`nurture'). Settling this `nature vs. nurture' debate for nearby radio galaxies, which can be studied in great detail, is vital for understanding the properties and evolution of radio galaxies throughout the Universe. We propose to observe the radio galaxy NGC 612 where previous observations have detected the presence of a large-scale HI bridge between the host galaxy and a nearby galaxy NGC 619. We request a total of 13 hrs in the 750m array-configuration to determine whether or not the 100 kpc-scale radio source morphology is directly related to the intergalactic distribution of neutral hydrogen gas.

  2. IYL Blog: Astronomers travel in time and space with light

    Science.gov (United States)

    Mather, John C.

    2015-01-01

    also using light to find out whether we are alone in the universe. The Kepler observatory showed that thousands of stars blink a little when their orbiting planets pass between us and them, and other observatories use light to measure the wobble of stars as their planets pull on them. Eventually, we will find out whether planets like Earth have atmospheres like Earth's too - with water, carbon dioxide, oxygen, methane, and other gases that would be evidence of photosynthetic life. I think in a few decades we will have evidence that some planets do have life, and it will be done using light for remote chemical analysis. Also, astronomers at the SETI project are using light (long wavelength light we can pick up with radio telescopes) to look for signals from intelligent civilizations. That's a harder project because we don't know what to look for. But if we wanted to send signals all the way across the Milky Way, we could do it with laser beams, and if somebody over there knew what to look for, he or she could decode the message. On with the search! Dr. John C. Mather is a Senior Astrophysicist and is the Senior Project Scientist for the James Webb Space Telescope at NASA's Goddard Space Flight Center in Greenbelt, MD. His research centers on infrared astronomy and cosmology. With the Cosmic Background Explorer (COBE) team, he showed that the cosmic microwave background radiation has a blackbody spectrum within 50 parts per million, confirming the expanding universe model (aka the Big Bang Theory) to extraordinary accuracy, and initiating the study of cosmology as a precision science. The COBE team also made the first map of the hot and cold spots in the background radiation. The COBE maps have been confirmed and improved by two succeeding space missions, the Wilkinson Microwave Anisotropy Probe (WMAP, built by GSFC with Princeton University), and the Planck mission built by ESA. Based on these maps, astronomers have now developed a "standard model" of cosmology and have

  3. The GMRT 150 MHz all-sky radio survey. First alternative data release TGSS ADR1

    Science.gov (United States)

    Intema, H. T.; Jagannathan, P.; Mooley, K. P.; Frail, D. A.

    2017-02-01

    We present the first full release of a survey of the 150 MHz radio sky, observed with the Giant Metrewave Radio Telescope (GMRT) between April 2010 and March 2012 as part of the TIFR GMRT Sky Survey (TGSS) project. Aimed at producing a reliable compact source survey, our automated data reduction pipeline efficiently processed more than 2000 h of observations with minimal human interaction. Through application of innovative techniques such as image-based flagging, direction-dependent calibration of ionospheric phase errors, correcting for systematic offsets in antenna pointing, and improving the primary beam model, we created good quality images for over 95 percent of the 5336 pointings. Our data release covers 36 900 deg2 (or 3.6 π steradians) of the sky between -53° and +90° declination (Dec), which is 90 percent of the total sky. The majority of pointing images have a noise level below 5 mJy beam-1 with an approximate resolution of 25''×25'' (or 25''×25''/ cos(Dec-19°) for pointings south of 19° declination). We have produced a catalog of 0.62 Million radio sources derived from an initial, high reliability source extraction at the seven sigma level. For the bulk of the survey, the measured overall astrometric accuracy is better than two arcseconds in right ascension and declination, while the flux density accuracy is estimated at approximately ten percent. Within the scope of the TGSS alternative data release (TGSS ADR) project, the source catalog, as well as 5336 mosaic images (5°×5°) and an image cutout service, are made publicly available at the CDS as a service to the astronomical community. Next to enabling a wide range of different scientific investigations, we anticipate that these survey products will provide a solid reference for various new low-frequency radio aperture array telescopes (LOFAR, LWA, MWA, SKA-low), and can play an important role in characterizing the epoch-of-reionisation (EoR) foreground. The TGSS ADR project aims at

  4. Ham radio for dummies

    CERN Document Server

    Silver, H Ward

    2013-01-01

    An ideal first step for learning about ham radio Beyond operating wirelessly, today's ham radio operators can transmit data and pictures; use the Internet, laser, and microwave transmitters; and travel to places high and low to make contact. This hands-on beginner guide reflects the operational and technical changes to amateur radio over the past decade and provides you with updated licensing requirements and information, changes in digital communication (such as the Internet, social media, and GPS), and how to use e-mail via radio. Addresses the critical use of ham radio for replacing downe

  5. electrode array

    African Journals Online (AJOL)

    PROF EKWUEME

    A geoelectric investigation employing vertical electrical soundings (VES) using the Ajayi - Makinde Two-Electrode array and the ... arrangements used in electrical D.C. resistivity survey. These include ..... Refraction Tomography to Study the.

  6. Radiography of Spanish Radio

    Directory of Open Access Journals (Sweden)

    Dra. Emma Rodero Antón

    2007-01-01

    Full Text Available In its eighty years of existence, radio has been always characterized to adapt to the social, cultural and technological transformations. Thus it has been until this moment. Nevertheless, some years ago, the authors and professionals of this medium have been detecting a stagnation that affects to its structure. At a time in continuous technological evolution, radio demands a deep transformation. For that reason, from the conviction of which the future radio, public and commercial, will necessarily have to renew itself, in this paper we establish ten problems and their possible solutions to the radio crisis in order to draw an x-ray of radio in Spain. Radio has future, but it is necessary to work actively by it. That the radio continues being part of sound of our life, it will depend on the work of all: companies, advertisers, professionals, students, investigators and listeners.

  7. Thirty years of astronomical discovery with UKIRT

    CERN Document Server

    Davies, John; Robson, Ian; The Scientific Achievement of the United Kingdom InfraRed Telescope

    2013-01-01

    These are the proceedings of an international meeting hosted by the Royal Observatory, Edinburgh, to commemorate the 30th anniversary of the dedication of the UKIRT, the United Kingdom InfraRed Telescope. The volume comprises 31 professional level papers. The first part of the book has 10 thorough reviews of the conception, design and build of the telescope, as well as accounts of some its key instruments such as IRCAM (the common-user infrared camera), CGS4 (the fourth Cooled Grating Spectrometer) and the Wide Field Camera. The second part of the book comprises 14 reviews of scientific achievements during its twenty years of visitor mode operations. The final part of the book is a series of 7 reviews of the results from the multiple surveys being done as part of UKIDSS (UKIRT Infrared Deep Sky Survey). The authors are all experts in their respective fields, for example instrument scientists, operations staff and leading astronomers.

  8. Simon Newcomb: America's Unofficial Astronomer Royal

    Science.gov (United States)

    Graham, John

    2007-10-01

    Bill Carter and Merri Sue Carter Mantazas; xiii + 213 pp.; ISBN 1-59113-803-5 2006; $26.95 This book introduced me to a commanding figure in American science from the late nineteenth century: Simon Newcomb. Newcomb has been called the nineteenth-century equivalent of Carl Sagan and Albert Einstein. He rose from humble beginnings to be the preeminent American astronomer of his generation. He made basic, far-reaching, and enduring contributions to positional astronomy and planetary dynamics. On the more practical side, he determined a remarkably accurate value for the velocity of light, one within 0.01% of the value accepted today. His work provided an experimental grounding for the special and general theories of relativity to be formulated by Einstein in the coming twentieth century.

  9. Multinational History of Strasbourg Astronomical Observatory

    CERN Document Server

    Heck, André

    2005-01-01

    Strasbourg Astronomical Observatory is quite an interesting place for historians: several changes of nationality between France and Germany, high-profile scientists having been based there, big projects born or installed in its walls, and so on. Most of the documents circulating on the history of the Observatory and on related matters have however been so far poorly referenced, if at all. This made necessary the compilation of a volume such as this one, offering fully-documented historical facts and references on the first decades of the Observatory history, authored by both French and German specialists. The experts contributing to this book have done their best to write in a way understandable to readers not necessarily hyperspecialized in astronomy nor in the details of European history. After an introductory chapter by the Editor, contributions by Wolfschmidt and by Duerbeck respectively deal extensively with the German periods and review people and instrumentation, while another paper by Duerbeck is more...

  10. Shirakatsi Astronomical and Natural Philosophical Views

    Science.gov (United States)

    Mkrtchyan, Lilit

    2016-12-01

    Our work is aimed at presenting Shirakatsi astronomical and natural philosophical views. Karl Anania Shirakatsi is classified as one of the world-class intellectual geniuses. He was endowed with exceptional talent and analyzing scientific understanding of natural phenomena. He refers his philosophical works to almost all fields of science, cosmography, mathematics, calendarology, historiography, etc. Shirakatsy's earnings of natural science and natural philosophy in medieval is too big He was the first prominent scholar and thinker of his time, creating a unique, comprehensive gitapilisopayakan system that still feeds the human mind. The scientific value of Shirakatsi has great importance not only for Armenians but also for the whole world of science, history, culture and philosophy. Shirakatsi can be considered not only national but also universal greatness.

  11. From Casual Stargazer to Amateur Astronomer

    Science.gov (United States)

    Eagle, Dave

    The word amateur stems from the French word Amour, meaning "Lover Of". And there is a whole army of amateur astronomers around the world who just love doing astronomy. They don't get paid for the privilege of experiencing the sky in all its glory, but by making detailed observations they do make a very important contribution towards the Science. These observations are especially useful when organized as a collective effort. Citizen science has really taken off in the last few years and the GAIA project will soon be producing so much data, that the professionals just will not have enough manpower to tackle all the data. They will rely on amateurs sitting on their computers at home. But it is under a dark sky that astronomy really comes alive. The fact that you have picked up this book, must mean that you are interested in taking the hobby a step forward.

  12. Leslie Peltier, Amateur Astronomer and Observer Extraordinaire

    Science.gov (United States)

    Corbin, B. G.

    2003-12-01

    Leslie Copus Peltier, (Jan. 2, 1900-May 10, 1980) was called "the world's greatest non-professional astronomer" by none other than Harlow Shapley, and also referred to as the "the world's greatest living amateur astronomer". He began observing variable stars on March 1, 1918 with an observation of R. Leonis and at the time of his death had made a total of 132,123 observations of variable stars. These were reported to the AAVSO on a consecutive monthly basis stretching from 1918 to his death in 1980. As of October 2003, he was still on AAVSO's list of the top 25 observers in its history. Born on a farm near Delphos, Ohio, his parents were well read and their home was filled with books on different subjects, including nature guides. As a young man he studied the flora and fauna of the area and in 1915 began his study of the heavens with Vega being the first star he identified. After the purchase of a 2-inch spyglass, his observations of variable stars began to be noticed by professional astronomers and the AAVSO loaned him a 4-inch Mogey refractor; shortly thereafter Henry Norris Russell of Princeton loaned him via the AAVSO a 6-inch refractor, a comet seeker of short focus. He discovered 12 comets, 10 of which carry his name, and 6 novae or recurring novae. His design of the "Merry-Go-Round Observatory" was a novel approach with the whole observatory revolving around the observer while seated in his observing chair. Miami University (Ohio) later donated to him their 12-inch Clark refractor with its dome. His first book, Starlight Nights: The Adventures of a Star-Gazer, appeared in 1965. This autobiography, an ode to the joys of observing both the night sky and nature, was written in beautifully descriptive language that helped lead countless readers into astronomy. Departing from astronomy, in 1977 he published The Place on Jennings Creek. Written in the style of the 19th century naturalist, the book was devoted to his family's home, Brookhaven, and its natural

  13. Fundamental and applied aspects of astronomical seeing

    International Nuclear Information System (INIS)

    Coulman, C.E.

    1985-01-01

    It is pointed out that despite recent advances in the use of spacecraft as observatory platforms, much astronomy is still conducted from the surface of the earth. The literature on astronomical seeing and observatory site selection is widely scattered throughout journals and conference reports concerned with various disciplines. This survey has the objective to represent the state of the subject up to 1982. A description of the history and prospects of the considered subject is presented, and the optics of seeing are examined. The meteorology of seeing is discussed, taking into account aspects of micrometeorology and small-scale turbulence near the surface, the diurnal cycle in the planetary boundary layer, the temperature structure above the planetary boundary layer, and the effects of terrain. Attention is given to the calculation of system performance from microthermal data, optical methods for the measurement of seeing, and techniques for minimizing image-degrading effects of the atmosphere. 279 references

  14. Preparing Colorful Astronomical Images and Illustrations

    Science.gov (United States)

    Levay, Z. G.; Frattare, L. M.

    2001-12-01

    We present techniques for using mainstream graphics software, specifically Adobe Photoshop and Illustrator, for producing composite color images and illustrations from astronomical data. These techniques have been used with numerous images from the Hubble Space Telescope to produce printed and web-based news, education and public presentation products as well as illustrations for technical publication. While Photoshop is not intended for quantitative analysis of full dynamic range data (as are IRAF or IDL, for example), we have had much success applying Photoshop's numerous, versatile tools to work with scaled images, masks, text and graphics in multiple semi-transparent layers and channels. These features, along with its user-oriented, visual interface, provide convenient tools to produce high-quality, full-color images and graphics for printed and on-line publication and presentation.

  15. Dacic Ancient Astronomical Research in Sarmizegetuza

    Directory of Open Access Journals (Sweden)

    Emanuel George Oprea

    2015-11-01

    Full Text Available The actual Romanian territory belongs to Carpatho-Danubian Space and to Ancient Europe. The Ancient European Society was a vast cultural entity based on a theocratic, matriarchal society, peaceful and art creating.Temples of Sarmizegetusa have given rise to several theories over time, proven by historians with the most diverse arguments. The largest complex of temples and sanctuaries was founded in Sarmizegetusa Regia, the Dacian’s main fortress and ancient capital of Dacia in the time of King Decebalus. The mysterious form of settlements has led researchers to the conclusion that the locations were astronomical observation shrines. Among the places of Dacian worship in Orastie Mountains the most impressive is the Great Circular Sanctuary, used to perform some celestial observations, and also as original solar calendar. This paper had the purpose to re-discover the Dacian Civilization and Dacian cosmogony based on the accumulated knowledge upon our country’s past.

  16. Astronomical knowledge transmission through illustrated Aratea manuscripts

    CERN Document Server

    Dolan, Marion

    2017-01-01

    This carefully researched monograph is a historical investigation of the illustrated Aratea astronomical manuscript and its many interpretations over the centuries. Aratus' 270 B.C.E. Greek poem describing the constellations and astrological phenomena was translated and copied over 800 years into illuminated manuscripts that preserved and illustrated these ancient stories about the constellations. The Aratea survives in its entirety due to multiple translations from Greek to Latin and even to Arabic, with many illuminated versions being commissioned over the ages. The survey encompasses four interrelated disciplines: history of literature, history of myth, history of science, and history of art. Aratea manuscripts by their nature are a meeting place of these distinct branches, and the culling of information from historical literature and from the manuscripts themselves focuses on a wider, holistic view; a narrow approach could not provide a proper prospective. What is most essential to know about this work is...

  17. How astronomers watch the birth of stars

    International Nuclear Information System (INIS)

    Little, L.

    1984-01-01

    The paper describes the recent progress in stellar evolution, due to the new techniques in infrared and radio astronomy. The latter techniques have revealed where the stars are born, and the way the stars actually form. The nature of the molecular clouds where the stars form, star formation regions, collapse in molecular clouds, gas flows within clouds and cores of clouds have also been investigated using the new techniques and new telescopes. (U.K.)

  18. Astronomical calibration of the Maastrichtian (Late Cretaceous)

    DEFF Research Database (Denmark)

    Husson, Dorothée; Galbrun, Bruno; Laskar, Jacques

    2011-01-01

    /Pg boundary, considering the uncertainty of the long-term variation of the 405 ka eccentricity cycle. The first proposal provides a Cretaceous/Paleogene boundary age of 65.59 ± 0.07 Ma and the second an age of 66 ± 0.07 Ma, which is coherent with the most recent radio-isotopic datings. Magnetochron boundaries...... and the Campanian/Maastrichtian boundary are dated relative to these numerical ages of the K/Pg boundary....

  19. World's fastest and most sensitive astronomical camera

    Science.gov (United States)

    2009-06-01

    The next generation of instruments for ground-based telescopes took a leap forward with the development of a new ultra-fast camera that can take 1500 finely exposed images per second even when observing extremely faint objects. The first 240x240 pixel images with the world's fastest high precision faint light camera were obtained through a collaborative effort between ESO and three French laboratories from the French Centre National de la Recherche Scientifique/Institut National des Sciences de l'Univers (CNRS/INSU). Cameras such as this are key components of the next generation of adaptive optics instruments of Europe's ground-based astronomy flagship facility, the ESO Very Large Telescope (VLT). ESO PR Photo 22a/09 The CCD220 detector ESO PR Photo 22b/09 The OCam camera ESO PR Video 22a/09 OCam images "The performance of this breakthrough camera is without an equivalent anywhere in the world. The camera will enable great leaps forward in many areas of the study of the Universe," says Norbert Hubin, head of the Adaptive Optics department at ESO. OCam will be part of the second-generation VLT instrument SPHERE. To be installed in 2011, SPHERE will take images of giant exoplanets orbiting nearby stars. A fast camera such as this is needed as an essential component for the modern adaptive optics instruments used on the largest ground-based telescopes. Telescopes on the ground suffer from the blurring effect induced by atmospheric turbulence. This turbulence causes the stars to twinkle in a way that delights poets, but frustrates astronomers, since it blurs the finest details of the images. Adaptive optics techniques overcome this major drawback, so that ground-based telescopes can produce images that are as sharp as if taken from space. Adaptive optics is based on real-time corrections computed from images obtained by a special camera working at very high speeds. Nowadays, this means many hundreds of times each second. The new generation instruments require these

  20. Reconfigurable, Cognitive Software-Defined Radio

    Science.gov (United States)

    Bhat, Arvind

    2015-01-01

    Software-defined radio (SDR) technology allows radios to be reconfigured to perform different communication functions without using multiple radios to accomplish each task. Intelligent Automation, Inc., has developed SDR platforms that switch adaptively between different operation modes. The innovation works by modifying both transmit waveforms and receiver signal processing tasks. In Phase I of the project, the company developed SDR cognitive capabilities, including adaptive modulation and coding (AMC), automatic modulation recognition (AMR), and spectrum sensing. In Phase II, these capabilities were integrated into SDR platforms. The reconfigurable transceiver design employs high-speed field-programmable gate arrays, enabling multimode operation and scalable architecture. Designs are based on commercial off-the-shelf (COTS) components and are modular in nature, making it easier to upgrade individual components rather than redesigning the entire SDR platform as technology advances.

  1. PHYSICAL CONSTRAINTS ON FAST RADIO BURSTS

    Energy Technology Data Exchange (ETDEWEB)

    Luan, Jing; Goldreich, Peter, E-mail: jingluan@caltech.edu [California Institute of Technology, Pasadena, CA 91125 (United States)

    2014-04-20

    Fast radio bursts (FRBs) are isolated, ms radio pulses with dispersion measure (DM) of order 10{sup 3} pc cm{sup –3}. Galactic candidates for the DM of high latitude bursts detected at GHz frequencies are easily dismissed. DM from bursts emitted in stellar coronas are limited by free-free absorption and those from H II regions are bounded by the nondetection of associated free-free emission at radio wavelengths. Thus, if astronomical, FRBs are probably extragalactic. FRB 110220 has a scattering tail of ∼5.6 ± 0.1 ms. If the electron density fluctuations arise from a turbulent cascade, the scattering is unlikely to be due to propagation through the diffuse intergalactic plasma. A more plausible explanation is that this burst sits in the central region of its host galaxy. Pulse durations of order ms constrain the sizes of FRB sources implying high brightness temperatures that indicates coherent emission. Electric fields near FRBs at cosmological distances would be so strong that they could accelerate free electrons from rest to relativistic energies in a single wave period.

  2. PHYSICAL CONSTRAINTS ON FAST RADIO BURSTS

    International Nuclear Information System (INIS)

    Luan, Jing; Goldreich, Peter

    2014-01-01

    Fast radio bursts (FRBs) are isolated, ms radio pulses with dispersion measure (DM) of order 10 3 pc cm –3 . Galactic candidates for the DM of high latitude bursts detected at GHz frequencies are easily dismissed. DM from bursts emitted in stellar coronas are limited by free-free absorption and those from H II regions are bounded by the nondetection of associated free-free emission at radio wavelengths. Thus, if astronomical, FRBs are probably extragalactic. FRB 110220 has a scattering tail of ∼5.6 ± 0.1 ms. If the electron density fluctuations arise from a turbulent cascade, the scattering is unlikely to be due to propagation through the diffuse intergalactic plasma. A more plausible explanation is that this burst sits in the central region of its host galaxy. Pulse durations of order ms constrain the sizes of FRB sources implying high brightness temperatures that indicates coherent emission. Electric fields near FRBs at cosmological distances would be so strong that they could accelerate free electrons from rest to relativistic energies in a single wave period

  3. Effectiveness of Amateur Astronomers as Informal Science Educators

    Science.gov (United States)

    Gibbs, Michael G.; Berendsen, Margaret

    2007-01-01

    The Astronomical Society of the Pacific (ASP) conducted a national survey of in-service teachers participating in Project ASTRO. The survey results document (1) the value that teachers place on supplemental astronomy education provided by professional and amateur astronomers, and (2) the difference that teachers perceive in the value provided by…

  4. Astronomical Books and Charts in the Book of Bibliographie Coreenne

    Directory of Open Access Journals (Sweden)

    Ki-Won Lee

    2008-06-01

    Full Text Available We investigate astronomical materials listed in the book of Bibliographie Coreenne written by Maurice Courant. He classified ancient Korean books into nine Divisions (部 and thirty six Classes (類, and published them as three volumes (ranging from 1894 to 1896 and one supplement (in 1901. In total, 3,821 books including astronomical ones are listed together with information on physical size, possessional place, bibliographical note, and so forth. Although this book is an essential one in the field of Korea bibliography and contains many astronomical materials such as Cheon-Mun-Ryu-Cho 天文類抄, Si-Heon-Seo 時憲書, and Cheon-Sang-Yeol-Cha-Bun-Ya-Ji-Do 天象列次分野之圖, it has not been well known to the public nor to astronomical society. Of 3,821 catalogues, we found that about 50 Items (種 are related to astronomy or astrology, and verified that most of them are located in the Kyujanggak Royal Library 奎章閣. We also found an unknown astronomical chart, Hon-Cheon-Chong-Seong-Yeol-Cha-Bun-Ya-Ji-Do 渾天總星列次分野之圖. Because those astronomical materials are not well known to international astronomical community and there have been few studies on the materials in Korea, we here introduce and review them, particularly with the astronomical viewpoint.

  5. Astronomical Books and Charts in the Book of Bibliographie Coreenne

    Science.gov (United States)

    Lee, Ki-Won; Yang, Hong-Jin; Park, Myeong-Gu

    2008-06-01

    We investigate astronomical materials listed in the book of Bibliographie Coréenne written by Maurice Courant. He classified ancient Korean books into nine Divisions (?) and thirty six Classes (?), and published them as three volumes (ranging from 1894 to 1896) and one supplement (in 1901). In total, 3,821 books including astronomical ones are listed together with information on physical size, possessional place, bibliographical note, and so forth. Although this book is an essential one in the field of Korea bibliography and contains many astronomical materials such as Cheon-Mun-Ryu-Cho ????, Si-Heon-Seo ??????, and Cheon-Sang-Yeol-Cha-Bun-Ya-Ji-Do ????????, it has not been well known to the public nor to astronomical society. Of 3,821 catalogues, we found that about 50 Items (?) are related to astronomy or astrology, and verified that most ! of them are located in the Kyujanggak Royal Library ???. We also found an unknown astronomical chart, Hon-Cheon-Chong-Seong-Yeol-Cha-Bun-Ya-Ji-Do ??????????. Because those astronomical materials are not well known to international astronomical community and there have been few studies on the materials in Korea, we here introduce and review them, particularly with the astronomical viewpoint.

  6. The contribution of the Georges Heights Experimental Radar Antenna to Australian radio astronomy

    Science.gov (United States)

    Orchiston, Wayne; Wendt, Harry

    2017-12-01

    During the late 1940s and throughout the1950s Australia was one of the world’s foremost astronomical nations owing primarily to the dynamic Radio Astronomy Group within the Commonwealth Scientific and Industrial Organisation’s Division of Radiophysics based in Sydney. The earliest celestial observations were made with former WWII radar antennas and simple Yagi aerials attached to recycled radar receivers, before more sophisticated purpose-built radio telescopes of various types were designed and developed. One of the recycled WWII antennas that was used extensively for pioneering radio astronomical research was an experimental radar antenna that initially was located at the Division’s short-lived Georges Heights Field Station but in 1948 was relocated to the new Potts Hill Field Station in suburban Sydney. In this paper we describe this unique antenna, and discuss the wide-ranging solar, galactic and extragalactic research programs that it was used for.

  7. The Victorian Amateur Astronomer: Independent Astronomical Research in Britain 1820-1920

    Science.gov (United States)

    Chapman, Allan

    1999-01-01

    This is the first book to look in detail at amateur astronomy in Victorian Britain. It deals with the technical issues that were active in Victorian astronomy, and reviews the problems of finance, patronage and the dissemination of scientific ideas. It also examines the relationship between the amateur and professional in Britain. It contains a wealth of previously unpublished biographical and anecdotal material, and an extended bibliography with notes incorporating much new scholarship. In The Victorian Amateur Astronomer, Allan Chapman shows that while on the continent astronomical research was lavishly supported by the state, in Britain such research was paid for out of the pockets of highly educated, wealthy gentlemen the so-called Grand Amateurs . It was these powerful individuals who commissioned the telescopes, built the observatories, ran the learned societies, and often stole discoveries from their state-employed colleagues abroad. In addition to the Grand Amateurs , Victorian Britain also contained many self-taught amateurs. Although they belonged to no learned societies, these people provide a barometer of the popularity of astronomy in that age. In the late 19th century, the comfortable middle classes clergymen, lawyers, physicians and retired military officers took to astronomy as a serious hobby. They formed societies which focused on observation, lectures and discussions, and it was through this medium that women first came to play a significant role in British astronomy. Readership: Undergraduate and postgraduate students studying the history of science or humanities, professional historians of science, engineering and technology, particularly those with an interest in astronomy, the development of astronomical ideas, scientific instrument makers, and amateur astronomers.

  8. Indexing data cubes for content-based searches in radio astronomy

    Science.gov (United States)

    Araya, M.; Candia, G.; Gregorio, R.; Mendoza, M.; Solar, M.

    2016-01-01

    Methods for observing space have changed profoundly in the past few decades. The methods needed to detect and record astronomical objects have shifted from conventional observations in the optical range to more sophisticated methods which permit the detection of not only the shape of an object but also the velocity and frequency of emissions in the millimeter-scale wavelength range and the chemical substances from which they originate. The consolidation of radio astronomy through a range of global-scale projects such as the Very Long Baseline Array (VLBA) and the Atacama Large Millimeter/submillimeter Array (ALMA) reinforces the need to develop better methods of data processing that can automatically detect regions of interest (ROIs) within data cubes (position-position-velocity), index them and facilitate subsequent searches via methods based on queries using spatial coordinates and/or velocity ranges. In this article, we present the development of an automatic system for indexing ROIs in data cubes that is capable of automatically detecting and recording ROIs while reducing the necessary storage space. The system is able to process data cubes containing megabytes of data in fractions of a second without human supervision, thus allowing it to be incorporated into a production line for displaying objects in a virtual observatory. We conducted a set of comprehensive experiments to illustrate how our system works. As a result, an index of 3% of the input size was stored in a spatial database, representing a compression ratio equal to 33:1 over an input of 20.875 GB, achieving an index of 773 MB approximately. On the other hand, a single query can be evaluated over our system in a fraction of second, showing that the indexing step works as a shock-absorber of the computational time involved in data cube processing. The system forms part of the Chilean Virtual Observatory (ChiVO), an initiative which belongs to the International Virtual Observatory Alliance (IVOA) that

  9. The Evolution of the Stellar Hosts of Radio Galaxies

    International Nuclear Information System (INIS)

    Lacy, Mark; Bunker, Andrew J.; Ridgway, Susan E.

    2000-01-01

    We present new near-infrared images of z>0.8 radio galaxies from the flux-limited 7C-iii sample of radio sources for which we have recently obtained almost complete spectroscopic redshifts. The 7C objects have radio luminosities ≅20 times fainter than 3C radio galaxies at a given redshift. The absolute magnitudes of the underlying host galaxies and their scale sizes are only weakly dependent on radio luminosity. Radio galaxy hosts at z∼2 are significantly brighter than the hosts of radio-quiet quasars at similar redshifts and the recent model AGN hosts of Kauffmann and Haehnelt. There is no evidence for strong evolution in scale size, which shows a large scatter at all redshifts. The hosts brighten significantly with redshift, consistent with the passive evolution of a stellar population that formed at z(greater-or-similar sign)3. This scenario is consistent with studies of host galaxy morphology and submillimeter continuum emission, both of which show strong evolution at z(greater-or-similar sign)2.5. The lack of a strong ''redshift cutoff'' in the radio luminosity function to z>4 suggests that the formation epoch of the radio galaxy host population lasts (greater-or-similar sign)1 Gyr, from z(greater-or-similar sign)5 to z∼3. We suggest these facts are best explained by models in which the most massive galaxies and their associated AGN form early because of high baryon densities in the centers of their dark matter haloes. (c) 2000 The American Astronomical Society

  10. Combined ultraviolet studies of astronomical sources

    Science.gov (United States)

    Baliunas, S. L.; Dupree, A. K.; Elvis, M.; Huchra, J. P.; Kenyon, S.; Raymond, J. C.

    1986-01-01

    Topics addressed include: Cygnus Loop; P Cygni profiles in dwarf novae; YY Gem; nova shells; HZ Herculis; activity cycles in cluster giants; Alpha Ori; metal deficient giant stars; ultraviolet spectra of symbiotic stars detected by the Very Large Array; time variability in symbiotic stars; blue galaxies; and quasistellar objects with X-ray spectra.

  11. Database-Driven Analyses of Astronomical Spectra

    Science.gov (United States)

    Cami, Jan

    2012-03-01

    Spectroscopy is one of the most powerful tools to study the physical properties and chemical composition of very diverse astrophysical environments. In principle, each nuclide has a unique set of spectral features; thus, establishing the presence of a specific material at astronomical distances requires no more than finding a laboratory spectrum of the right material that perfectly matches the astronomical observations. Once the presence of a substance is established, a careful analysis of the observational characteristics (wavelengths or frequencies, intensities, and line profiles) allows one to determine many physical parameters of the environment in which the substance resides, such as temperature, density, velocity, and so on. Because of this great diagnostic potential, ground-based and space-borne astronomical observatories often include instruments to carry out spectroscopic analyses of various celestial objects and events. Of particular interest is molecular spectroscopy at infrared wavelengths. From the spectroscopic point of view, molecules differ from atoms in their ability to vibrate and rotate, and quantum physics inevitably causes those motions to be quantized. The energies required to excite vibrations or rotations are such that vibrational transitions generally occur at infrared wavelengths, whereas pure rotational transitions typically occur at sub-mm wavelengths. Molecular vibration and rotation are coupled though, and thus at infrared wavelengths, one commonly observes a multitude of ro-vibrational transitions (see Figure 13.1). At lower spectral resolution, all transitions blend into one broad ro-vibrational molecular band. The isotope. Molecular spectroscopy thus allows us to see a difference of one neutron in an atomic nucleus that is located at astronomical distances! Since the detection of the first interstellar molecules (the CH [21] and CN [14] radicals), more than 150 species have been detected in space, ranging in size from diatomic

  12. Filter arrays

    Science.gov (United States)

    Page, Ralph H.; Doty, Patrick F.

    2017-08-01

    The various technologies presented herein relate to a tiled filter array that can be used in connection with performance of spatial sampling of optical signals. The filter array comprises filter tiles, wherein a first plurality of filter tiles are formed from a first material, the first material being configured such that only photons having wavelengths in a first wavelength band pass therethrough. A second plurality of filter tiles is formed from a second material, the second material being configured such that only photons having wavelengths in a second wavelength band pass therethrough. The first plurality of filter tiles and the second plurality of filter tiles can be interspersed to form the filter array comprising an alternating arrangement of first filter tiles and second filter tiles.

  13. A very brief description of LOFAR the Low Frequency Array

    NARCIS (Netherlands)

    Falcke, H.D.; van Haarlem, M.P.; de Bruyn, A.G.; Braun, R.; Röttgering, H.J.A.; Stappers, B.W.; Boland, W.H.W.M.; Butcher, H.R.; de Geus, E.J.; Koopmans, L.V.; Fender, R.P.; Kuijpers, H.J.M.E.; Miley, G.K.; Schilizzi, R.T.; Vogt, C.; Wijers, R.A.M.J.; Wise, M.; Brouw, W.N.; Hamaker, J.P.; Noordam, J.E.; Oosterloo, T.; Bähren, L.; Brentjens, M.A.; Wijnholds, S.J.; Bregman, J.D.; van Cappellen, W.A.; Gunst, A.W.; Kant, G.W.; Reitsma, J.; van der Schaaf, K.; de Vos, C.M.

    2007-01-01

    LOFAR (Low Frequency Array) is an innovative radio telescope optimized for the frequency range 30 240 MHz. The telescope is realized as a phased aperture array without any moving parts. Digital beam forming allows the telescope to point to any part of the sky within a second. Transient buffering

  14. A very brief description of LOFAR - the Low Frequency Array

    NARCIS (Netherlands)

    Falcke, H.; Haarlem, M.P. van; Wijnholds, S.J.; Bregman, J.D.; Cappellen, W.A.; Gunst, A.W.; Kant, G.W.; Reitsma, J.; Schaaf, K. van der; Vos, C.M. de

    2006-01-01

    Abstract: LOFAR (Low Frequency Array) is an innovative radio telescope optimized for the frequency range 30-240 MHz. The telescope is realized as a phased aperture array without any moving parts. Digital beam forming allows the telescope to point to any part of the sky within a second. Transient

  15. A very brief description of LOFAR -- the Low Frequency Array

    NARCIS (Netherlands)

    Falcke, H.D.E.; Haarlem, M.P. van; Bruyn, A.G. de; Braun, R.; Röttgering, H.J.A.; Stappers, B.; Boland, W.H.W.M.; Butcher, H.R.; Geus, E.J. de; Koopmans, L.V.; Fender, R.P.; Kuijpers, H.J.M.E.; Miley, G.K.; Schilizzi, R.T.; Vogt, C.; Wijers, R.A.M.J.; Wise, M.W.; Brouw, W.N.; Hamaker, J.P.; Noordam, J.E.; Oosterloo, T.; Bähren, L.; Brentjens, M.A.; Wijnholds, S.J.; Bregman, J.D.; Cappellen, W.A. van; Gunst, A.W.; Kant, G.W.; Reitsma, J.; Schaaf, K. van der; Vos, C.M. de

    2007-01-01

    LOFAR (Low Frequency Array) is an innovative radio telescope optimized for the frequency range 30-240 MHz. The telescope is realized as a phased aperture array without any moving parts. Digital beam forming allows the telescope to point to any part of the sky within a second. Transient buffering

  16. THE RADIO PROPERTIES OF RADIO-LOUD NARROW-LINE SEYFERT 1 GALAXIES ON PARSEC SCALES

    Energy Technology Data Exchange (ETDEWEB)

    Gu, Minfeng; Chen, Yongjun; Shen, Zhiqiang [Shanghai Astronomical Observatory, Chinese Academy of Sciences, Shanghai 200030 (China); Komossa, S.; Zensus, J. A. [Max-Planck-Institut für Radioastronomie, Auf dem Hügel 69, D-53121 Bonn (Germany); Yuan, Weimin [Key Lab for Space Astronomy and Technology, National Astronomical Observatories, Chinese Academy of Sciences, Beijing 100012 (China); Wajima, Kiyoaki [Korea Astronomy and Space Science Institute, 776 Daedeokdae-ro, Yuseong, Daejeon 305-348 (Korea, Republic of); Zhou, Hongyan, E-mail: gumf@shao.ac.cn [Polar Research Institute of China, 451 Jinqiao Road, Shanghai 200136 (China)

    2015-11-15

    We present the detection of the compact radio structures of 14 radio-loud narrow-line Seyfert 1 (NLS1) galaxies from Very Long Baseline Array (VLBA) observations at 5 GHz performed in 2013. While 50% of the sources of our sample show a compact core only, the remaining 50% exhibit a core-jet structure. The measured brightness temperatures of the cores range from 10{sup 8.4} to 10{sup 11.4} K with a median value of 10{sup 10.1} K, indicating that the radio emission is from non-thermal jets, and that, likely, most sources are not strongly beamed, thus implying a low jet speed in these radio-loud NLS1 galaxies. In combination with archival data taken at multiple frequencies, we find that seven sources show flat or even inverted radio spectra, while steep spectra are revealed in the remaining seven objects. Although all of these sources are very radio-loud with R > 100, their jet properties are diverse in terms of their milliarcsecond (mas) scale (parsec scale) morphology and their overall radio spectral shape. The evidence for slow jet speeds (i.e., less relativistic jets), in combination with the low kinetic/radio power, may offer an explanation for the compact VLBA radio structure in most sources. The mildly relativistic jets in these high accretion rate systems are consistent with a scenario where jets are accelerated from the hot corona above the disk by the magnetic field and the radiation force of the accretion disk. Alternatively, a low jet bulk velocity can be explained by low spin in the Blandford–Znajek mechanism.

  17. Senior radio listeners

    DEFF Research Database (Denmark)

    Blaakilde, Anne Leonora

    Radiobroadcasting and the hardware materialization of radio have during the 20th century changed significantly, which means that senior radio listeners have travelled along with this evolution from large, impressive radio furnitures to DAB and small, wireless, mobile devices, and from grave...... and solemn radio voices to lightharted, laughing and chatting speakers. Senior radio listerners have experienced the development and refinements of technique, content and genres. It is now expected of all media users that they are capable of crossing media, combining, juggling and jumping between various...... media platforms, not the least when listening to radio. The elder generation is no exception from this. Recently, for instance, the Danish public broadcast DR has carried out an exodus of programmes targeted for the senior segment. These programmes are removed from regular FM and sent to DAB receivers...

  18. U.S. and European ALMA Partners Sign Agreement Green Light for World's Most Powerful Radio Observatory

    Science.gov (United States)

    2003-02-01

    Dr. Rita Colwell, director of the U.S. National Science Foundation (NSF), and Dr. Catherine Cesarsky, director general of the European Southern Observatory (ESO), today signed a historic agreement jointly to construct and operate ALMA, the Atacama Large Millimeter Array, the world's largest and most powerful radio telescope operating at millimeter and sub-millimeter wavelengths. "With this agreement, we usher in a new age of research in astronomy," said Dr. Colwell. "By working together in this truly global partnership, the international astronomy community will be able to ensure the research capabilities needed to meet the long-term demands of our scientific enterprise, and we will be able to study and understand our Universe in ways that have previously been beyond our vision." ALMA Array Artist's Conception of ALMA Array in Compact Configuration (Click on Image for Larger Version) Other Images Available: Artist's conception of the antennas for the Atacama Large Millimeter Array Moonrise over ALMA test equipment near Cerro Chajnantor, Chile VertexRSI antenna at the VLA test site Dr. Cesarsky also commented, "This agreement signifies the start of a great project of contemporary astronomy and astrophysics. Representing Europe, and in collaboration with many laboratories and institutes on this continent, we together look forward toward wonderful research projects. With ALMA, we may learn how the earliest galaxies in the Universe really looked like, to mention but one of the many eagerly awaited opportunities with this marvelous facility." When complete in 2011, ALMA will be an array of 64, 12-meter radio antennas that will work together as one telescope to study millimeter and sub-millimeter wavelength light from space. These wavelengths of the electromagnetic spectrum, which cross the critical boundary between infrared and microwave radiation, hold the key to understanding such processes as planet and star formation, the formation of early galaxies and galaxy

  19. Thermal Design and Thermal Behaviour of Radio Telescopes and their Enclosures

    CERN Document Server

    Greve, Albert

    2010-01-01

    Radio telescopes as well as communication antennas operate under the influence of gravity, temperature and wind. Among those, temperature influences may degrade the performance of a radio telescope through transient changes of the focus, pointing, path length and sensitivity, often in an unpredictable way. Thermal Design and Thermal Behaviour of Radio Telescopes and their Enclosures reviews the design and construction principles of radio telescopes in view of thermal aspects and heat transfer with the variable thermal environment; it explains supporting thermal model calculations and the application and efficiency of thermal protection and temperature control; it presents many measurements illustrating the thermal behaviour of telescopes in the environment of their observatory sites. The book benefits scientists and radio/communication engineers, telescope designers and construction firms as well as telescope operators, observatory staff, but also the observing astronomer who is directly confronted with the t...

  20. MASER: Measuring, Analysing, Simulating low frequency Radio Emissions.

    Science.gov (United States)

    Cecconi, B.; Le Sidaner, P.; Savalle, R.; Bonnin, X.; Zarka, P. M.; Louis, C.; Coffre, A.; Lamy, L.; Denis, L.; Griessmeier, J. M.; Faden, J.; Piker, C.; André, N.; Genot, V. N.; Erard, S.; King, T. A.; Mafi, J. N.; Sharlow, M.; Sky, J.; Demleitner, M.

    2017-12-01

    The MASER (Measuring, Analysing and Simulating Radio Emissions) project provides a comprehensive infrastructure dedicated to low frequency radio emissions (typically Radioastronomie de Nançay and the CDPP deep archive. These datasets include Cassini/RPWS, STEREO/Waves, WIND/Waves, Ulysses/URAP, ISEE3/SBH, Voyager/PRA, Nançay Decameter Array (Routine, NewRoutine, JunoN), RadioJove archive, swedish Viking mission, Interball/POLRAD... MASER also includes a Python software library for reading raw data.

  1. A CLUSTER OF COMPACT RADIO SOURCES IN W40

    International Nuclear Information System (INIS)

    RodrIguez, Luis F.; Rodney, Steven A.; Reipurth, Bo

    2010-01-01

    We present deep 3.6 cm radio continuum observations of the H II region W40 obtained using the Very Large Array (VLA) in its A and B configurations. We detect a total of 20 compact radio sources in a region of 4' x 4', with 11 of them concentrated in a band with 30'' of extent. We also present JHK photometry of the W40 cluster taken with the QUIRC instrument on the University of Hawaii 2.2 m telescope. These data reveal that 15 of the 20 VLA sources have infrared counterparts, and 10 show radio variability with periods less than 20 days. Based on these combined radio and IR data, we propose that eight of the radio sources are candidate ultracompact H II regions, seven are likely to be young stellar objects, and two may be shocked interstellar gas.

  2. Exotic Molecules in Space: A Coordinated Astronomical Laboratory and Theoretical Study

    Science.gov (United States)

    Stringfellow, Guy (Technical Monitor); Thaddeus, Patrick

    2004-01-01

    The final report covers the two year of a grant which represents a direct continuation of NASA NAG5-4050, with the same title as before. It is dedicated as before to the discovery and characterization of new astrophysical molecules. The four years (two of the original grant plus two years extension) have been extremely productive, yielding many new discoveries of astronomical interest at both radio and optical wavelengths, and the publication or submission of the 49 papers listed below. These articles have appeared or will soon appear in the leading refereed journals of astrophysics, chemical physics, physics, or molecular spectroscopy. One is a major invited review (#27) for Moleculur Physics. One of our other invited reviews published in Spectrochimica Acta in 2001 was recently awarded the Sir Harold Thompson Memorial Award, annually given to the best paper in that journal. Michael McCarthy has recently been awarded the Broida Prize.

  3. The 2013 Summer Undergraduate Research Internship Program at the Pisgah Astronomical Research Institute

    Science.gov (United States)

    Castelaz, Michael W.; Cline, J. D.; Whitworth, C.; Clavier, D.; Barker, T.

    2014-01-01

    Pisgah Astronomical Research Institute (PARI) offers summer undergraduate research internships. PARI has received support for the internships from the EMC Corporation, private donations, private foundations, and through a collaboration with the Pisgah Astronomical Research and Education Center of the University of North Carolina - Asheville. The internship program began in 2001 with 4 students. This year 10 funded students participated. Mentors for the interns include PARI’s Directors of Science, Education, and Information Technology and visiting faculty who are members of the PARI Research Faculty Affiliate program. Students work with mentors on radio and optical astronomy research, electrical engineering for robotic control of instruments, software development for instrument control and and science education by developing curricula and multimedia and teaching high school students in summer programs at PARI. At the end of the summer interns write a paper about their research which is published in the PARI Summer Student Proceedings. Students are encouraged to present their research at AAS Meetings. We will present a summary of specific research conducted by the students with their mentors.

  4. The Summer Undergraduate Research Internship Program at the Pisgah Astronomical Research Institute

    Science.gov (United States)

    Cline, J. Donald; Castelaz, M.; Whitworth, C.; Clavier, D.; Owen, L.; Barker, T.

    2012-01-01

    Pisgah Astronomical Research Institute (PARI) offers summer undergraduate research internships. PARI has received support for the internships from the NC Space Grant Consortium, NSF awards for public science education, private donations, private foundations, and through a collaboration with the Pisgah Astronomical Research and Education Center of the University of North Carolina - Asheville. The internship program began in 2001 with 4 students. This year 7 funded students participated in 2011. Mentors for the interns include PARI's Science, Education, and Information Technology Directors and visiting faculty who are members of the PARI Research Affiliate Faculty program. Students work with mentors on radio and optical astronomy research, electrical engineering for robotic control of instruments, software development for instrument control and software for citizen science projects, and science education by developing curricula and multimedia and teaching high school students in summer programs at PARI. At the end of the summer interns write a paper about their research which is published in the PARI Summer Student Proceedings. Several of the students have presented their results at AAS Meetings. We will present a summary of specific research conducted by the students with their mentors, the logistics for hosting the PARI undergraduate internship program, and plans for growth based on the impact of an NSF supported renovation to the Research Building on the PARI campus.

  5. Astronomical Content in Rongorongo Tablet Keiti

    DEFF Research Database (Denmark)

    Wieczorek, Rafal

    2011-01-01

    Th e fi eld of rongorongo research: the study of Easter Island’s native script is in a peculiar state at the moment. While relative progress has been made in structural and statistical analysis in the last decades, at the level of both single glyphs as well as entire texts, little to no advanceme...... has been achieved in the actual decipherment. To shed new light on rongorongo research, a hypothesis regarding the contents of tablet Keiti, one of the 25 obtained artifacts, is proposed. Th e content, as well as the meaning, of all but one of these 25 rongorongo texts is still unknown....... In this publication, an interpretation for the recto side of tablet Keiti is presented. It is argued that the tablet contains astronomical observations or instructions regarding the Rapa Nui lunar calendar, and is similar in content to the only other rongorongo text whose function has been partially ascertained......: tablet Mamari. If the calendrical contents of this artifact were confi rmed, this would be a major boost to our understanding of Oceania’s only native script....

  6. Book Review: Scientific Writing for Young Astronomers

    Science.gov (United States)

    Uyttenhove, Jos

    2011-12-01

    EDP Sciences, Les Ulis, France. Part 1 : 162 pp. € 35 ISBN 978-2-7598-0506-8 Part 2 : 298 pp. € 60 ISBN 978-2-7598-0639-3 The journal Astronomy & Astrophysics (A&A) and EDP Sciences decided in 2007 to organize a School on the various aspects of scientific writing and publishing. In 2008 and 2009 Scientific Writing for Young Astronomers (SWYA) Schools were held in Blankenberge (B) under the direction of Christiaan Sterken (FWO-VUB). These two books (EAS publication series, Vol. 49 and 50) reflect the outcome of these Schools. Part 1 contains a set of contributions that discuss various aspects of scientific publication; it includes A&A Editors' view of the peer review and publishing process. A very interesting short paper by S.R. Pottasch (Kapteyn Astronomical Institute, Groningen, and one of the two first Editors-in Chief of A&A) deals with the history of the creation of the journal Astronomy & Astrophysics. Two papers by J. Adams et al. (Observatoire de Paris) discuss language editing, including a detailed guide for any non-native user of the English language. In 2002 the Board of Directors decided that all articles in A&A must be written in clear and correct English. Part 2 consists of three very extensive and elaborated papers by Christiaan Sterken, supplying guidelines to PhD students and postdoctoral fellows to help them compose scientific papers for different forums (journals, proceedings, thesis, etc.). This part is of interest not only for young astronomers but it is very useful for scholars of all ages and disciplines. Paper I "The writing process" (60 pp.) copes with the preparation of manuscripts, with communicating with editors and referees and with avoiding common errors. Delicate problems on authorship, refereeing, revising multi-authored papers etc. are treated in 26 FAQ's. Paper II "Communication by graphics" (120 pp.) is entirely dedicated to the important topic of communication with images, graphs, diagrams, tables etc. Design types of graphs

  7. Conceptualizing Astronomical Distances for Urban Populations

    Science.gov (United States)

    Popinchalk, Mark; Olson, Kristen; Ingber, Jenny; O'Brien, Mariel

    2017-01-01

    Students living in urban environments may have a washed-out night sky, but their enthusiasm for astronomy can still shine bright. As an educator, it can sometimes be a challenge to see the opportunities afforded by city living to the teaching of astronomy; however, several benefits can be identified. For example, the intrinsic understanding children have of the distances and scales involved in their everyday life is enhanced when they live in a regimented urban structure. This existing understanding of scale is critical to building a foundation for later conceptualizing of the universe.Leveraging the assets of New York City and the resources found in the American Museum of Natural History, The Science and Nature Program offers students (PreK through 8th grade) robust science learning experiences. To address concepts important for studying astronomy, we present a novel twist on the classic lesson “Earth as a Peppercorn,” by scaling the solar system to the size of New York City. Using local landmarks and their distance in relation to the Museum to represent the planets, students can use their prior knowledge of their surroundings to appreciate the impressive scale of our neighborhood in space in the context of their own neighborhoods. We correlate the activity with NGSS standards, present preliminary feedback on it’s success, and discuss the opportunities to apply a similar model lesson to other astronomical systems.

  8. Electronic Publishing and The American Astronomical Society

    Science.gov (United States)

    Milkey, R. W.

    1999-12-01

    Electronic Publishing has created, and will continue to create, new opportunities and challenges for representing scientific work in new media and formats. The AAS will position itself to take advantage of these, both for newly created works and for improved representation of works already published. It is the view of the AAS that we hold the works that we publish in trust for our community and are obligated to protect the integrity of these works and to assure that they continue to be available to the research community. Assignment of copyright to the AAS by the author plays a central role in the preservation of the integrity and accessability of the literature published by the American Astronomical Society. In return for such assignment the AAS allows the author to freely use the work for his/her own purpose and to control the grant of permission to third parties to use such materials. The AAS retains the right to republish the work in whatever format or medium, and to retain the rights after the author's death. Specific advantages to this approach include: Assurance of the continued availability of the materials to the research and educational communities; A guarantee of the intellectual integrity of the materials in the archive; Stimulation of the development of new means of presentation or of access to the archival literature; and Provision of a uniformity of treatment for copyright issues and to relieve the individual authors of much of the administrative work.

  9. Is astronomical research appropriate for developing countries?

    Science.gov (United States)

    Snowden, Michael S.

    An unproductive 45-cm astronomical telescope, given by JICA (Japan) to Sri Lanka, raises general questions as to the reasons for unproductive pure science in developing countries. Before installation, site, maintenance, and scientific objectives were discussed. The facility was launched with a conference organised by the UN Office for Outer Space Affairs. Unfortunately, no research or significant education has resulted after four years. The annual operating cost is U.S. $5000 per year, including salary for a trainee, maintenance, and a modest promotional programme. Comparison with a similar installation in Auckland suggests lack of funding or technical competence do not explain the failure in Sri Lanka. The facility in New Zealand, on the roof of Auckland University's Physics Department, has a slightly smaller budget but has led to modest but useful research and teaching. Lack of financial backing and expertise are often blamed for weak science in developing countries, but examination shows most of these countries have adequately skilled people, and plenty of resources for religion and military. General lack of motivation for science appears to be the principal reason. This lack of interest and highly inefficient bureaucracies are common to scientifically unproductive countries. They mostly lack the cultural and philosophical base of the European Renaissance that motivate the pursuit of modern science, an activity that violates human preferences. There are excellent facilities (ESO, SAAO, Cerro Tololo, and GONG) in some of these same countries, when administered from the West.

  10. Spectral Energy Distribution and Radio Halo of NGC 253 at Low Radio Frequencies

    Energy Technology Data Exchange (ETDEWEB)

    Kapińska, A. D.; Staveley-Smith, L.; Meurer, G. R.; For, B.-Q. [International Centre for Radio Astronomy Research (ICRAR), University of Western Australia, 35 Stirling Hwy, WA 6009 (Australia); Crocker, R. [Research School of Astronomy and Astrophysics, Australian National University, Canberra, ACT 2611 (Australia); Bhandari, S.; Callingham, J. R.; Gaensler, B. M.; Hancock, P. J.; Lenc, E. [ARC Centre of Excellence for All-Sky Astrophysics (CAASTRO), Sydney NSW (Australia); Hurley-Walker, N.; Seymour, N. [International Centre for Radio Astronomy Research (ICRAR), Curtin University, Bentley, WA 6102 (Australia); Offringa, A. R. [Netherlands Institute for Radio Astronomy (ASTRON), P.O. Box 2, 7990 AA Dwingeloo (Netherlands); Hanish, D. J. [Spitzer Science Center, California Institute of Technology, MC 220-6, 1200 East California Boulevard, Pasadena, CA 91125 (United States); Ekers, R. D.; Bell, M. E. [CSIRO Astronomy and Space Science (CASS), P.O. Box 76, Epping, NSW 1710 (Australia); Dwarakanath, K. S. [Raman Research Institute, Bangalore 560080 (India); Hindson, L. [Centre of Astrophysics Research, University of Hertfordshire, College Lane, Hatfield AL10 9AB (United Kingdom); Johnston-Hollitt, M. [School of Chemical and Physical Sciences, Victoria University of Wellington, P.O. Box 600, Wellington 6140 (New Zealand); McKinley, B., E-mail: anna.kapinska@uwa.edu.au [School of Physics, The University of Melbourne, Parkville, VIC 3010 (Australia); and others

    2017-03-20

    We present new radio continuum observations of NGC 253 from the Murchison Widefield Array at frequencies between 76 and 227 MHz. We model the broadband radio spectral energy distribution for the total flux density of NGC 253 between 76 MHz and 11 GHz. The spectrum is best described as a sum of a central starburst and extended emission. The central component, corresponding to the inner 500 pc of the starburst region of the galaxy, is best modeled as an internally free–free absorbed synchrotron plasma, with a turnover frequency around 230 MHz. The extended emission component of the spectrum of NGC 253 is best described as a synchrotron emission flattening at low radio frequencies. We find that 34% of the extended emission (outside the central starburst region) at 1 GHz becomes partially absorbed at low radio frequencies. Most of this flattening occurs in the western region of the southeast halo, and may be indicative of synchrotron self-absorption of shock-reaccelerated electrons or an intrinsic low-energy cutoff of the electron distribution. Furthermore, we detect the large-scale synchrotron radio halo of NGC 253 in our radio images. At 154–231 MHz the halo displays the well known X-shaped/horn-like structure, and extends out to ∼8 kpc in the z -direction (from the major axis).

  11. Serbian Astronomers in Science Citation Index in the XX Century

    Science.gov (United States)

    Dimitrijevic, Milan S.

    The book is written paralelly in Serbian and English. The presence of works of Serbian astronomers and works in astronomical journals published by other Serbian scientists, in Science Citation Index within the period from 1945 up to the end of 2000, has been analyzed. Also is presented the list of 38 papers which had some influence on the development of astronomy in the twentieth century. A review of the development of astronomy in Serbia in the last century is given as well. Particular attention is payed to the Astronomical Observatory, the principal astronomical institution in Serbia, where it is one of the oldest scientific organizations and the only autonomous astronomical institute. Its past development forms an important part of the history of science and culture in these regions. In the book is also considered and the history of the university teaching of astronomy in Serbia after the second world war. First of all the development of the Chair of Astronomy at the Faculty of Mathematics in Belgrade, but also the teaching of astronomy at University in Novi Sad, Ni and Kragujevac is discussed. In addition to professional Astronomy, well developed in Serbia is also the amateur Astronomy. In the review is first of all included the largest and the oldest organization of amateur-astronomers in Serbia, founded in 1934. Besides, here are the Astronomical Society "Novi Sad", ADNOS and Research Station "Petnica". In Valjevo, within the framework of the Society of researchers "Vladimir Mandic - Manda", there is active also the Astronomical Group. In Kragujevac, on the roof of the Institute of Physics of the Faculty of Sciences, there is the "Belerofont" Observatory. In Ni, at the close of the sixties and the start of the seventies, there was operating a branch of the Astronomical Society "Rudjer Bokovic", while at the Faculty of Philosophy there existed in the period 1976-1980 the "Astro-Geophysical Society". In the year 1996 there was founded Astronomical Society

  12. Astronomical Observatory of Belgrade from 1924 to 1955

    Science.gov (United States)

    Radovanac, M.

    2014-12-01

    History of the Astronomical Observatory in Belgrade, as the presentation is done here, become the field of interest to the author of the present monograph in early 2002. Then, together with Luka C. Popovic, during the Conference "Development of Astronomy among Serbs II" held in early April of that year, he prepared a paper entitled "Astronomska opservatorija tokom Drugog Svetskog rata" (Astronomical Observatory in the Second World War). This paper was based on the archives material concerning the Astronomical Observatory which has been professionally bearing in mind the author's position the subject of his work.

  13. Ecos del Cosmos: A radio astroexperience at the Universitat de Valencia

    Science.gov (United States)

    Marco, E.; Ballesteros, F. J.; Ortiz-Gil, A.

    2017-03-01

    During the last three years Ecos del Cosmos has been a radio program dedicated to spreading astronomical hot news to the Universitat de València community and beyond, and also topics of general astronomical interest. To do this, this program by Ràdio Universitat has conducted live interviews with researchers, explored relationships of astronomy with humanities and society, performed contests and explained in a simple way the main monthly ephemerides. A version of Ecos del Cosmos was broadcasted in the Onda Cero’s summer program ''Jelo en verano''conducted by Arturo Tellez.

  14. The far-infrared–radio correlation in MS0451-03

    CSIR Research Space (South Africa)

    Randriamampandry, SM

    2014-12-01

    Full Text Available .1093/mnras/stu2411 The far-infrared–radio correlation in MS0451-03 S. M. Randriamampandry,1,2‹ S. M. Crawford,1 C. M. Cress,2,3 K. M. Hess,4 M. Vaccari,2 E. M. Wilcots,5 M. A. Bershady5 and G. D. Wirth6 1South African Astronomical Observatory, PO Box 9... 2009) in galaxy clusters. Despite studies looking at the multiwavelength properties of galaxies in distant C© 2014 The Authors Published by Oxford University Press on behalf of the Royal Astronomical Society by guest on D ecem ber 17, 2014 http...

  15. Super-Sharp Radio 'Eye' Remeasuring the Universe

    Science.gov (United States)

    2011-02-01

    Using the super-sharp radio "vision" of astronomy's most precise telescope, scientists have extended a directly-measured "yardstick" three times farther into the cosmos than ever before, an achievement with important implications for numerous areas of astrophysics, including determining the nature of Dark Energy, which constitutes 70 percent of the Universe. The continent-wide Very Long Baseline Array (VLBA) also is redrawing the map of our home Galaxy and is poised to yield tantalizing new information about extrasolar planets, among many other cutting-edge research projects. The VLBA provides the greatest ability to see fine detail, called resolving power, of any telescope in the world. It can produce images hundreds of times more detailed than those from the Hubble Space Telescope -- power equivalent to sitting in New York and reading a newspaper in Los Angeles. This power allows astronomers to make precise cosmic measurements with far-ranging implications for research within our own Galaxy and far beyond. New measurements with the VLBA have placed a galaxy called NGC 6264 at a distance of 450 million light-years from Earth, with an uncertainty of no more than 9 percent. This is the farthest distance ever directly measured, surpassing a measurement of 160 million light-years to another galaxy in 2009. Previously, distances beyond our own Galaxy have been estimated through indirect methods. "Our direct, geometric measurements are independent of the assumptions and complications inherent in other techniques," said James Braatz, of the National Radio Astronomy Observatory (NRAO), who worked with Cheng-Yu Kuo, of the University of Virginia and NRAO. Fine-tuning the measurement of ever-greater distances is vital to determining the expansion rate of the Universe, which helps theorists narrow down possible explanations for the nature of Dark Energy. Different models of Dark Energy predict different values for the expansion rate, known as the Hubble Constant. "Solving

  16. Astronomical virtual observatory and the place and role of Bulgarian one

    Science.gov (United States)

    Petrov, Georgi; Dechev, Momchil; Slavcheva-Mihova, Luba; Duchlev, Peter; Mihov, Bojko; Kochev, Valentin; Bachev, Rumen

    2009-07-01

    Virtual observatory could be defined as a collection of integrated astronomical data archives and software tools that utilize computer networks to create an environment in which research can be conducted. Several countries have initiated national virtual observatory programs that combine existing databases from ground-based and orbiting observatories, scientific facility especially equipped to detect and record naturally occurring scientific phenomena. As a result, data from all the world's major observatories will be available to all users and to the public. This is significant not only because of the immense volume of astronomical data but also because the data on stars and galaxies has been compiled from observations in a variety of wavelengths-optical, radio, infrared, gamma ray, X-ray and more. In a virtual observatory environment, all of this data is integrated so that it can be synthesized and used in a given study. During the autumn of the 2001 (26.09.2001) six organizations from Europe put the establishment of the Astronomical Virtual Observatory (AVO)-ESO, ESA, Astrogrid, CDS, CNRS, Jodrell Bank (Dolensky et al., 2003). Its aims have been outlined as follows: - To provide comparative analysis of large sets of multiwavelength data; - To reuse data collected by a single source; - To provide uniform access to data; - To make data available to less-advantaged communities; - To be an educational tool. The Virtual observatory includes: - Tools that make it easy to locate and retrieve data from catalogues, archives, and databases worldwide; - Tools for data analysis, simulation, and visualization; - Tools to compare observations with results obtained from models, simulations and theory; - Interoperability: services that can be used regardless of the clients computing platform, operating system and software capabilities; - Access to data in near real-time, archived data and historical data; - Additional information - documentation, user-guides, reports

  17. The Expanded Very Large Array Project

    Science.gov (United States)

    Perley, Rick

    2012-10-01

    The Expanded Very Large Array Project, begun in 2001, is now completed -- on time, on budget, and ``on spec.'' The major goal of the project was to multiply the key observational capabilities of the Very Large Array -- the world's most powerful, versatile, and productive radio telescope -- by a factor of at least an order of magnitude by implementation of modern technologies. The result of the project is an operationally new telescope -- renamed the Jansky Very Large Array -- which is capable of new science unimagined in 1980, when the original VLA was completed. In this talk, I will review the goals of the project, and describe the new capabilities of the Jansky Very Large Array. Already, the array is providing fabulous new insights into the physics of the universe,and I will spend the majority of the time describing examples of new results.

  18. An Astronomer In The Classroom: Observatoire de Paris's Partnership Between Teachers and Astronomers

    Science.gov (United States)

    Doressoundiram, A.; Barban, C.

    2006-08-01

    The Observatoire de Paris is offering a partnership between teachers and astronomers. The principle is simple: any teacher wishing to undertake a pedagogical project in astronomy, in the classroom or involving the entire school, can request the help of a mentor. An astronomer from the Observatoire de Paris will then follow the teacher's project progress and offer advice and scientific support throughout the school year. The projects may take different forms: construction projects (models, instruments), lectures, posters, exhibitions, etc. The type of assistance offered is as varied as the projects: lecture(s) in class, telephone and e-mail exchanges, visits to the Observatoire; an almost made-to-measure approach that delighted the thirty or so groups that benefited such partnership in the 2005-2006 academic year. And this number is continuously growing. There was a rich variety of projects undertaken, from mounting a show and building a solar clock to visiting a high altitude observatory, or resolving the mystery of Jupiter's great red spot. The Universe and its mysteries fascinate the young (and the not so- young) and provide a multitude of scientific topics that can be exploited in class. Astronomy offers the added advantage of being a multidisciplinary field. Thus, if most projects are generally initiated by a motivated teacher, they are often taken over by teachers in other subjects: Life and Earth Sciences (SVT), history, mathematics, French, and so forth. The project may consist in an astronomy workshop or be part of the school curriculum. Whatever the case, the astronomer's task is not to replace the teacher or the textbooks, but to propose activities or experiments that are easy to implement. Representing the Solar system on a school-yard scale, for instance, is a perfect way to make youngsters realize that the Universe consists mostly of empty space. There is no shortage of topics, and the students' enthusiasm, seldom absent, is the best reward for the

  19. Ionosphere and Radio Communication

    Indian Academy of Sciences (India)

    The upperionosphere is used for radio communication and navigationas it reflects long, medium, as well as short radio waves. Sincesolar radiation is the main cause of the existence of ionosphere,any variation in the radiations can affect the entireradio communication system. This article attempts to brieflyintroduce the ...

  20. Writing for Radio.

    Science.gov (United States)

    Tupper, Marianna S.

    1995-01-01

    Describes a 24-hour commercial radio station simulation class project for eighth-grade language arts. Students wrote their own scripts, chose music and were disc jockeys on their own music and talk shows, and prepared news and traffic reports. Guest speakers from actual commercial radio came in to discuss issues such as advertising, censorship,…

  1. Valuing commercial radio licences

    NARCIS (Netherlands)

    Kerste, M.; Poort, J.; van Eijk, N.

    2015-01-01

    Within the EU regulatory framework, licensees for commercial radio broadcasting may be charged a fee to ensure optimal allocation of scarce resources but not to maximize public revenues. While radio licence renewal occurs in many EU countries, an objective, model-based approach for setting licence

  2. The Radio Jove Project

    Science.gov (United States)

    Thieman, J. R.

    2010-01-01

    The Radio love Project is a hands-on education and outreach project in which students, or any other interested individuals or groups build a radio telescope from a kit, operate the radio telescope, transmit the resulting signals through the internet if desired, analyze the results, and share the results with others through archives or general discussions among the observers. Radio love is intended to provide an introduction to radio astronomy for the observer. The equipment allows the user to observe radio signals from Jupiter, the Sun, the galaxy, and Earth-based radiation both natural and man-made. The project was started through a NASA Director's Discretionary Fund grant more than ten years ago. it has continued to be carried out through the dedicated efforts of a group of mainly volunteers. Dearly 1500 kits have been distributed throughout the world. Participation can also be done without building a kit. Pre-built kits are available. Users can also monitor remote radio telescopes through the internet using free downloadable software available through the radiosky.com website. There have been many stories of prize-winning projects, inspirational results, collaborative efforts, etc. We continue to build the community of observers and are always open to new thoughts about how to inspire the observers to still greater involvement in the science and technology associated with Radio Jove.

  3. Boom Booom Net Radio

    DEFF Research Database (Denmark)

    Grimshaw, Mark Nicholas; Yong, Louisa; Dobie, Ian

    1999-01-01

    of an existing Internet radio station; Boom Booom Net Radio. Whilst necessity dictates some use of technology-related terminology, wherever possible we have endeavoured to keep such jargon to a minimum and to either explain it in the text or to provide further explanation in the appended glossary....

  4. Construction of a Radio-Telescope Prototype in the 12 GHz Band

    Science.gov (United States)

    Ordóñez, J.; Quijano, A.; Luna, A.

    2017-07-01

    Radio astronomy is important in the branch of the Astronomy that studies the celestial bodies through their emissions in the domain of the radio waves, to obtain information of these bodies, astronomers must design new types of telescopes that can capture radiation at different wavelengths, including radio telescopes. This paper presents the construction of a prototype of an educational radio telescope, which is made using materials that are easily accessible and inexpensive. The construction of a radio telescope, will allow to carry out research in the field of radio astronomy, since at present it has not been possible to penetrate this branch due to the lack of an adequate equipment in the University of Nariño. The issues that are addressed in the construction of this instrument, its use and the analysis of the data, are very varied and with a high content of multidiciplinariety, gathering basic topics in areas such as astrophysics, physics, electronics, computing, mechanics, which are necessary for Concrete the efficient use of this instrument. For the development of the project, it counts with the advice of the director and researcher of the astronomical observatory of the University of Nariño MSc. Alberto Quijano Vodniza and Dr. Abraham Luna Castellanos of the National Institute of Astrophysics, Optics and Electronics INAOE. In addition to the construction of radiotelescope the final phase consists of the storage and analysis of data obtained with the observation of some celestial bodies that comply with The range in the 12 GHz band for study.

  5. The TF1 Radio Astronomy Working Group in the Andean ROAD: goals and challenges for 2025

    Science.gov (United States)

    Chaparro Molano, G.

    2017-07-01

    Since the creation of the Andean Regional Office of Astronomy for Development (OAD) of the International Astronomical Union, one of the main goals has been to foster a scientific culture of radio astronomy in countries of the central and northern Andes (Bolivia, Colombia, Ecuador, Perú, and Venezuela). For this reason, Andean ROAD Task Force 1 (Research and Education in Universities) created the Radio Astronomy Working Group to set a path along which collaborative endeavors can grow and yield scientific results. The first official meeting of the Working Group took place in Bogotá, Colombia during the 2nd Astronomá en los Andes Workshop (2015) where scientists actively developing projects in radio astronomy set goals for the near future, such as improving mobility for researchers and students, developing collaborations in related areas such as engineering and data science, and building transnational collaborations aiming at developing VLBI across the countries of the Andean ROAD and beyond. In this poster, I present current projects and associated research groups (ROAS - Perú, SiAMo - Colombia, Alfa-Orion UTP - Colombia, RAIG - Chile) and discuss goalposts and current challenges in the development of transnational radioastronomical projects. As a case study, I present the development and early astronomical results of the privately funded UECCI 4m Radio Telescope for 21 cm line observations in Bogotá, Colombia.

  6. THE VLA SURVEY OF CHANDRA DEEP FIELD SOUTH. V. EVOLUTION AND LUMINOSITY FUNCTIONS OF SUB-MILLIJANSKY RADIO SOURCES AND THE ISSUE OF RADIO EMISSION IN RADIO-QUIET ACTIVE GALACTIC NUCLEI

    International Nuclear Information System (INIS)

    Padovani, P.; Mainieri, V.; Rosati, P.; Miller, N.; Kellermann, K. I.; Tozzi, P.

    2011-01-01

    We present the evolutionary properties and luminosity functions of the radio sources belonging to the Chandra Deep Field South Very Large Array survey, which reaches a flux density limit at 1.4 GHz of 43 μJy at the field center and redshift ∼5 and which includes the first radio-selected complete sample of radio-quiet active galactic nuclei (AGNs). We use a new, comprehensive classification scheme based on radio, far- and near-IR, optical, and X-ray data to disentangle star-forming galaxies (SFGs) from AGNs and radio-quiet from radio-loud AGNs. We confirm our previous result that SFGs become dominant only below 0.1 mJy. The sub-millijansky radio sky turns out to be a complex mix of SFGs and radio-quiet AGNs evolving at a similar, strong rate; non-evolving low-luminosity radio galaxies; and declining radio powerful (P ∼> 3 x 10 24 W Hz -1 ) AGNs. Our results suggest that radio emission from radio-quiet AGNs is closely related to star formation. The detection of compact, high brightness temperature cores in several nearby radio-quiet AGNs can be explained by the coexistence of two components, one non-evolving and AGN related and one evolving and star formation related. Radio-quiet AGNs are an important class of sub-millijansky sources, accounting for ∼30% of the sample and ∼60% of all AGNs, and outnumbering radio-loud AGNs at ∼< 0.1 mJy. This implies that future, large area sub-millijansky surveys, given the appropriate ancillary multiwavelength data, have the potential of being able to assemble vast samples of radio-quiet AGNs, bypassing the problems of obscuration that plague the optical and soft X-ray bands.

  7. Reducing Disparity in Radio-Isotopic and Astrochronology-Based Time Scales of the Late Eocene and Oligocene

    NARCIS (Netherlands)

    Sahy, Diana; Condon, Daniel J.; Hilgen, Frederik J.|info:eu-repo/dai/nl/102639876; Kuiper, Klaudia F.|info:eu-repo/dai/nl/258125772

    2017-01-01

    A significant discrepancy of up to 0.6 Myr exists between radio-isotopically calibrated and astronomically tuned time scales of the late Eocene-Oligocene. We explore the possible causes of this discrepancy through the acquisition of “high-precision” 206Pb/238U dating of zircons from 11 volcanic ash

  8. Ir A.H. de Voogt: life and career of a radio pioneer

    Science.gov (United States)

    Strom, R. G.

    2007-06-01

    There are probably few radio astronomers who would be able to recall A.H. de Voogt, which is unfortunate, but at the same time unsurprising: for he published no original astronomical research, never carried out pioneering observations, nor is his name linked to either theoretical or instrumental breakthroughs. Yet he was described by the man who first observed the 21 cm hydrogen line from the Netherlands as a radio astronomy pioneer, at the very birth of the Dutch effort. He was, moreover, a trail blazer at the cutting edge of radio, not once but twice in his career. Without him it is unlikely that the 21 cm line would have been observed in the Netherlands in 1951, and arguably the H I mapping of the Milky Way under Jan Oort's leadership would have taken place much later, if at all. Radio astronomy observing itself might well have been compromised by interference had it not been for De Voogt's foresight. \\ Anthonet Hugo de Voogt (1892-1969) built, while still a teenager, one of the very first amateur radio stations (call letters VO: *** -/- - -) in Holland, earned the radio-telegrapher's diploma during his student days, and was intimately involved in the foundation of the Dutch Society for Radio-Telegraphy in 1916. Until the 1920s, he was very active in amateur radio and astronomy circles. Trained in electrical engineering at Delft, he joined the PTT (Post Office) as a telegraph engineer in 1919, worked his way through the ranks to become head of the telephone district of Breda in 1939, and was promoted to head the PTT Radio Service just days after the end of the war. As his department was responsible for overseas radio communication, he initiated a research effort to study radio propagation in the ionosphere and the effects of solar activity. To this end, he rescued a number of Würzburg-Riese 7.5-m radar antennas abandoned at the end of the war, made one available for Jan Oort's H I work, and launched a series of radio astronomical initiatives. His group also

  9. Spectroscopy for amateur astronomers recording, processing, analysis and interpretation

    CERN Document Server

    Trypsteen , Marc F M

    2017-01-01

    This accessible guide presents the astrophysical concepts behind astronomical spectroscopy, covering both the theory and the practical elements of recording, processing, analysing and interpreting your spectra. It covers astronomical objects, such as stars, planets, nebulae, novae, supernovae, and events such as eclipses and comet passages. Suitable for anyone with only a little background knowledge and access to amateur-level equipment, the guide's many illustrations, sketches and figures will help you understand and practise this scientifically important and growing field of amateur astronomy, up to the level of Pro-Am collaborations. Accessible to non-academics, it benefits many groups from novices and learners in astronomy clubs, to advanced students and teachers of astrophysics. This volume is the perfect companion to the Spectral Atlas for Amateur Astronomers, which provides detailed commented spectral profiles of more than 100 astronomical objects.

  10. Astronomical sketching a step-by-step introduction

    CERN Document Server

    Handy, Richard; Perez, Jeremy; Rix, Erika; Robbins, Sol

    2007-01-01

    This book presents the amateur with fine examples of astronomical sketches and step-by-step tutorials in each medium, from pencil to computer graphics programs. This unique book can teach almost anyone to create beautiful sketches of celestial objects.

  11. Database retrieval systems for nuclear and astronomical data

    International Nuclear Information System (INIS)

    Suda, Takuma; Korennov, Sergei; Otuka, Naohiko; Yamada, Shimako; Katsuta, Yutaka; Ohnishi, Akira; Kato, Kiyoshi; Fujimoto, Masayuki Y.

    2006-01-01

    Data retrieval and plot systems of nuclear and astronomical data are constructed on a common platform. Web-based systems will soon be opened to the users of both fields of nuclear physics and astronomy. (author)

  12. PPARC: Grid technology helps astronomers keep pace with the Universe

    CERN Multimedia

    2003-01-01

    "Intelligent Agent" computer programs are roaming the Internet and watching the skies. These programs, using Grid computing technology, will help astronomers detect some of the most dramatic events in the universe, such as massive supernova explosions (1 page).

  13. The Educational Activities of the Astronomical Society of the Pacific.

    Science.gov (United States)

    Fraknoi, Andrew

    1981-01-01

    Describes educational activities of the Astronomical Society of the Pacific including learning packets on various astronomy concepts, Morrison lectures, newspaper columns, teacher workshops, cosponsoring astronomy oriented lectures, and providing speakers for various groups. (DS)

  14. Lessons from the masters current concepts in astronomical image processing

    CERN Document Server

    2013-01-01

    There are currently thousands of amateur astronomers around the world engaged in astrophotography at increasingly sophisticated levels. Their ranks far outnumber professional astronomers doing the same and their contributions both technically and artistically are the dominant drivers of progress in the field today. This book is a unique collaboration of individuals, all world-renowned in their particular area, and covers in detail each of the major sub-disciplines of astrophotography. This approach offers the reader the greatest opportunity to learn the most current information and the latest techniques directly from the foremost innovators in the field today.   The book as a whole covers all types of astronomical image processing, including processing of eclipses and solar phenomena, extracting detail from deep-sky, planetary, and widefield images, and offers solutions to some of the most challenging and vexing problems in astronomical image processing. Recognized chapter authors include deep sky experts su...

  15. Tomographic array

    International Nuclear Information System (INIS)

    1976-01-01

    The configuration of a tomographic array in which the object can rotate about its axis is described. The X-ray detector is a cylindrical screen perpendicular to the axis of rotation. The X-ray source has a line-shaped focus coinciding with the axis of rotation. The beam is fan-shaped with one side of this fan lying along the axis of rotation. The detector screen is placed inside an X-ray image multiplier tube

  16. Tomographic array

    International Nuclear Information System (INIS)

    1976-01-01

    A tomographic array with the following characteristics is described. An X-ray screen serving as detector is placed before a photomultiplier tube which itself is placed in front of a television camera connected to a set of image processors. The detector is concave towards the source and is replacable. Different images of the object are obtained simultaneously. Optical fibers and lenses are used for transmission within the system

  17. Astronomical fire: Richard Carrington and the solar flare of 1859.

    Science.gov (United States)

    Clark, Stuart

    2007-09-01

    An explosion on the Sun in 1859, serendipitously witnessed by amateur astronomer Richard Carrington, plunged telegraphic communications into chaos and bathed two thirds of the Earth's skies in aurorae. Explaining what happened to the Sun and how it could affect Earth, 93 million miles away, helped change the direction of astronomy. From being concerned principally with charting the stars to aid navigation, astronomers became increasingly concerned with what the celestial objects were, how they behaved and how they might affect life on Earth.

  18. Applying artificial intelligence to astronomical databases - a surveyof applicable technology.

    Science.gov (United States)

    Rosenthal, D. A.

    This paper surveys several emerging technologies which are relevant to astronomical database issues such as interface technology, internal database representation, and intelligent data reduction aids. Among the technologies discussed are natural language understanding, frame and object representations, planning, pattern analysis, machine learning and the nascent study of simulated neural nets. These techniques will become increasingly important for astronomical research, and in particular, for applications with large databases.

  19. ARNICA, the Arcetri near-infrared camera: Astronomical performance assessment.

    Science.gov (United States)

    Hunt, L. K.; Lisi, F.; Testi, L.; Baffa, C.; Borelli, S.; Maiolino, R.; Moriondo, G.; Stanga, R. M.

    1996-01-01

    The Arcetri near-infrared camera ARNICA was built as a users' instrument for the Infrared Telescope at Gornergrat (TIRGO), and is based on a 256x256 NICMOS 3 detector. In this paper, we discuss ARNICA's optical and astronomical performance at the TIRGO and at the William Herschel Telescope on La Palma. Optical performance is evaluated in terms of plate scale, distortion, point spread function, and ghosting. Astronomical performance is characterized by camera efficiency, sensitivity, and spatial uniformity of the photometry.

  20. Preservation and maintenance of the astronomical sites in Armenia

    Science.gov (United States)

    Mickaelian, A. M.

    2008-01-01

    Astronomy in Armenia was popular since ancient times. There are signs of astronomical observations coming from a few thousands years ago. Two ancient observatories, Karahunge and Metzamor are especially well known. Karahunge is the Armenian twin of the Stonehenge and is even older. However, there is no proper attention from the state authorities and efforts are needed for preservation of such historical-astronomical monuments. The Byurakan Astrophysical Observatory (BAO) is the modern famous Armenian observatory founded in 1946 by the outstanding scientist Victor Ambartsumian. It was one of the world astronomical centres in 1950-s to 1970-s, and at present is the largest observatory in the Middle East area. As the ancient astronomical sites, Byurakan also needs a proper attitude from the state authorities and corresponding international organizations to preserve its values and importance for the present and future astronomical activities in the region, including its rich observational archive, telescopes, and human resources. Despite all the difficulties, the Armenian astronomers keep high international level of research and display various activities organizing international meetings and schools, preparing new young generation for the future research. The Armenian Astronomical Society (ArAS) is an affiliated member of EAS. Armenia has its Virtual Observatory project (ArVO) as well. The next Joint European and National Astronomy Meeting (JENAM-2007) will be held in Yerevan, Armenia, in August 2007. There are plans to organize astronomical tours to Armenia for making observations from various sites, including the ancient observatories. The future of astronomy in Armenia strongly depends on all of this activities and the proper attention both from state authorities and society.

  1. Limits on fast radio bursts at 145 MHz with ARTEMIS, a real-time software backend

    NARCIS (Netherlands)

    Karastergiou, A.; Chennamangalam, J.; Armour, W.; Williams, C.; Mort, B.; Dulwich, F.; Salvini, S.; Magro, A.; Roberts, S.; Serylak, M.; Doo, A.; Bilous, A.V.; Breton, R.P.; Falcke, H.; Grießmeier, J.M.; Hessels, J.W.T.; Keane, E.F.; Kondratiev, V.I.; Kramer, M.; van Leeuwen, J.; Noutsos, A.; Osłowski, S.; Sobey, C.; Stappers, B.W.; Weltevrede, P.

    2015-01-01

    Fast radio bursts (FRBs) are millisecond radio signals that exhibit dispersion larger than what the Galactic electron density can account for. We have conducted a 1446 h survey for FRBs at 145 MHz, covering a total of 4193 deg2 on the sky. We used the UK station of the low frequency array (LOFAR)

  2. Probing Atmospheric Electric Fields through Radio Emission from Cosmic-Ray-Induced Air Showers

    NARCIS (Netherlands)

    Scholten, Olaf; Trinh, Gia; Buitink, Stijn; Corstanje, Arthur; Ebert, Ute; Enriquez, Emilio; Falcke, Heino; Hoerandel, Joerg; Nelles, Anna; Schellart, Pim; Rachen, Joerg; Rutjes, Casper; ter Veen, Sander; Rossetto, Laura; Thoudam, Satyendra

    2016-01-01

    Energetic cosmic rays impinging on the atmosphere create a particle avalanche called an extensive air shower. In the leading plasma of this shower electric currents are induced that generate coherent radio wave emission that has been detected with LOFAR, a large and dense array of simple radio

  3. DARIS, a fleet of passive formation flying small satellites for low frequency radio astronomy

    NARCIS (Netherlands)

    Saks, Noah; Boonstra, Albert Jan; Rajan, Raj Thilak; Rajan, Raj; Bentum, Marinus Jan; Beliën, Frederik; van 't Klooster, Kees

    2010-01-01

    DARIS (Distributed Aperture Array for Radio Astronomy In Space) is a mission to conduct radio astronomy in the low frequency region from 1-10MHz. This region has not yet been explored, as the Earth's ionosphere is opaque to those frequencies, and so a space based observatory is the only solution.

  4. Local area networking in a radio quiet environment

    Science.gov (United States)

    Childers, Edwin L.; Hunt, Gareth; Brandt, Joseph J.

    2002-11-01

    The Green Bank facility of the National Radio Astronomy Observatory is spread out over 2,700 acres in the Allegheny Mountains of West Virginia. Good communication has always been needed between the radio telescopes and the control buildings. The National Radio Quiet Zone helps protect the Green Bank site from radio transmissions that interfere with the astronomical signals. Due to stringent Radio Frequency Interference (RFI) requirements, a fiber optic communication system was used for Ethernet transmissions on the site and coaxial cable within the buildings. With the need for higher speed communications, the entire network has been upgraded to use optical fiber with modern Ethernet switches. As with most modern equipment, the implementation of the control of the newly deployed Green Bank Telescope (GBT) depends heavily on TCP/IP. In order to protect the GBT from the commodity Internet, the GBT uses a non-routable network. Communication between the control building Local Area Network (LAN) and the GBT is implemented using a Virtual LAN (VLAN). This configuration will be extended to achieve isolation between trusted local user systems, the GBT, and other Internet users. Legitimate access to the site, for example by remote observers, is likely to be implemented using a virtual private network (VPN).

  5. Catherine Cesarsky - President Elect of the International Astronomical Union (IAU)

    Science.gov (United States)

    2003-07-01

    The General Assembly of the International Astronomical Union (IAU), meeting in Sydney (Australia), has appointed the ESO Director General, Dr. Catherine Cesarsky, as President Elect for a three-year period (2003-2006). The IAU is the world's foremost organisation for astronomy, uniting almost 9000 professional scientists on all continents. The IAU General Assembly also elected Prof. Ron Ekers (Australia) as President (2003 - 2006). Dr. Cesarsky will then become President of the IAU in 2006, when the General Assembly next meets in Prague (The Czech Republic). Dr. Cesarsky is the first woman scientist to receive this high distinction. "The election of Catherine Cesarsky as President-Elect of the IAU is an important recognition for a scientist who has made impressive contributions to various areas of modern astrophysics, from cosmic rays to the interstellar medium and cosmology" , commented the outgoing IAU President, Prof. Franco Pacini. "It is also an honour and an important accolade for the European astronomical community in general and ESO in particular." Dr. Cesarsky, who assumed the function as ESO Director General in 1999, was born in France. She received a degree in Physical Sciences at the University of Buenos Aires and graduated with a PhD in Astronomy in 1971 from Harvard University (Cambridge, Mass., USA). Afterwards she worked at the California Institute of Technology (CALTECH). In 1974, she became a staff member of the Service d'Astrophysique (SAp), Direction des Sciences de la Matière (DSM), Commissariat à l'Energie Atomique (CEA) (France). As Director of DSM (1994 - 1999), she was leading about 3000 scientists, engineers and technicians active within a broad spectrum of basic research programmes in physics, chemistry, astrophysics and earth sciences. Dr. Cesarsky is known for her successful research activities in several central areas of modern astrophysics. She first worked on the theory of cosmic ray propagation and acceleration, and galactic gamma

  6. Star Ware: The Amateur Astronomer's Guide to Choosing, Buying, and Using Telescopes and Accessories, 3rd Edition

    Science.gov (United States)

    Harrington, Philip S.

    2002-05-01

    Praise for the Second Edition of Star Ware "Star Ware is still a tour de force that any experienced amateur will find invaluable, and which hardware-minded beginners will thoroughly enjoy." -Robert Burnham, Sky & Telescope magazine "Star Ware condenses between two covers what would normally take a telescope buyer many months to accumulate." -John Shibley, Astronomy magazine Now more than ever, the backyard astronomer has a dazzling array of choices when it comes to telescope shopping-which can make choosing just the right sky-watching equipment a formidable challenge. In this revised and updated edition of Star Ware, the essential guide to buying astronomical equipment, award-winning astronomy writer Philip Harrington does the work for you, analyzing and exploring today's astronomy market and offering point-by-point comparisons of everything you need. Whether you're an experienced amateur astronomer or just getting started, Star Ware, Third Edition will prepare you to explore the farthest reaches of space with: Extensive, expanded reviews of leading models and accessories, including dozens of new products, to help you buy smart A clear, step-by-step guide to all aspects of purchasing everything from telescopes and binoculars to filters, mounts, lenses, cameras, film, star charts, guides and references, and much more Eleven new do-it-yourself projects for making unique astronomical equipment at home Easy tips on maintenance, photography, and star-mapping to help you get the most out of your telescope Lists of where to find everything astronomical, including Internet sites and Web resources; distributors, dealers, and conventions; and corporate listings for products and services

  7. Configuration Considerations for Low Frequency Arrays

    Science.gov (United States)

    Lonsdale, C. J.

    2005-12-01

    The advance of digital signal processing capabilities has spurred a new effort to exploit the lowest radio frequencies observable from the ground, from ˜10 MHz to a few hundred MHz. Multiple scientifically and technically complementary instruments are planned, including the Mileura Widefield Array (MWA) in the 80-300 MHz range, and the Long Wavelength Array (LWA) in the 20-80 MHz range. The latter instrument will target relatively high angular resolution, and baselines up to a few hundred km. An important practical question for the design of such an array is how to distribute the collecting area on the ground. The answer to this question profoundly affects both cost and performance. In this contribution, the factors which determine the anticipated performance of any such array are examined, paying particular attention to the viability and accuracy of array calibration. It is argued that due to the severity of ionospheric effects in particular, it will be difficult or impossible to achieve routine, high dynamic range imaging with a geographically large low frequency array, unless a large number of physically separate array stations is built. This conclusion is general, is based on the need for adequate sampling of ionospheric irregularities, and is independent of the calibration algorithms and techniques that might be employed. It is further argued that array configuration figures of merit that are traditionally used for higher frequency arrays are inappropriate, and a different set of criteria are proposed.

  8. A direct localization of a fast radio burst and its host.

    Science.gov (United States)

    Chatterjee, S; Law, C J; Wharton, R S; Burke-Spolaor, S; Hessels, J W T; Bower, G C; Cordes, J M; Tendulkar, S P; Bassa, C G; Demorest, P; Butler, B J; Seymour, A; Scholz, P; Abruzzo, M W; Bogdanov, S; Kaspi, V M; Keimpema, A; Lazio, T J W; Marcote, B; McLaughlin, M A; Paragi, Z; Ransom, S M; Rupen, M; Spitler, L G; van Langevelde, H J

    2017-01-04

    Fast radio bursts are astronomical radio flashes of unknown physical nature with durations of milliseconds. Their dispersive arrival times suggest an extragalactic origin and imply radio luminosities that are orders of magnitude larger than those of all known short-duration radio transients. So far all fast radio bursts have been detected with large single-dish telescopes with arcminute localizations, and attempts to identify their counterparts (source or host galaxy) have relied on the contemporaneous variability of field sources or the presence of peculiar field stars or galaxies. These attempts have not resulted in an unambiguous association with a host or multi-wavelength counterpart. Here we report the subarcsecond localization of the fast radio burst FRB 121102, the only known repeating burst source, using high-time-resolution radio interferometric observations that directly image the bursts. Our precise localization reveals that FRB 121102 originates within 100 milliarcseconds of a faint 180-microJansky persistent radio source with a continuum spectrum that is consistent with non-thermal emission, and a faint (twenty-fifth magnitude) optical counterpart. The flux density of the persistent radio source varies by around ten per cent on day timescales, and very long baseline radio interferometry yields an angular size of less than 1.7 milliarcseconds. Our observations are inconsistent with the fast radio burst having a Galactic origin or its source being located within a prominent star-forming galaxy. Instead, the source appears to be co-located with a low-luminosity active galactic nucleus or a previously unknown type of extragalactic source. Localization and identification of a host or counterpart has been essential to understanding the origins and physics of other kinds of transient events, including gamma-ray bursts and tidal disruption events. However, if other fast radio bursts have similarly faint radio and optical counterparts, our findings imply that

  9. Can Radio Telescopes Find Axions?

    Science.gov (United States)

    Kohler, Susanna

    2017-08-01

    axions. Now scientists Katharine Kelley and Peter Quinn at ICRAR, University of Western Australia, have explored how we might use next-generation radio telescopes to search for photons that were created by axions interacting with the magnetic fields of our galaxy.Hope for Next-Gen TelescopesPotential axion coupling strengths vs. mass (click for a closer look). The axion mass is thought to lie between a eV and a meV; two theoretical models are shown with dashed lines. The plot shows the sensitivity of the upcoming SKA and its precursors, ASKAP and MEERKAT. [KelleyQuinn 2017]By using a simple galactic halo model and reasonable assumptions for the central galactic magnetic field even taking into account the time dependence of the field Kelley and Quinn estimate the radio-frequency power density that we would observe at Earth from axions being converted to photons within the Milky Ways magnetic field.The authors then compare this signature to the detection capabilities of upcoming radio telescope arrays. They show that the upcoming Square Kilometer Array and its precursors should have the capability to detect signs of axions across large parts of parameter space.Kelley and Quinn conclude that theres good cause for optimism about future radio telescopes ability to detect axions. And if we did succeed in making a detection, it would be a triumph for both particle physics and astrophysics, finally providing an explanation for the universes dark matter.CitationKatharine Kelley and P. J. Quinn 2017 ApJL 845 L4. doi:10.3847/2041-8213/aa808d

  10. Solar observations with a low frequency radio telescope

    Science.gov (United States)

    Myserlis, I.; Seiradakis, J.; Dogramatzidis, M.

    2012-01-01

    We have set up a low frequency radio monitoring station for solar bursts at the Observatory of the Aristotle University in Thessaloniki. The station consists of a dual dipole phased array, a radio receiver and a dedicated computer with the necessary software installed. The constructed radio receiver is based on NASA's Radio Jove project. It operates continuously, since July 2010, at 20.1 MHz (close to the long-wavelength ionospheric cut-off of the radio window) with a narrow bandwidth (~5 kHz). The system is properly calibrated, so that the recorded data are expressed in antenna temperature. Despite the high interference level of an urban region like Thessaloniki (strong broadcasting shortwave radio stations, periodic experimental signals, CBs, etc), we have detected several low frequency solar radio bursts and correlated them with solar flares, X-ray events and other low frequency solar observations. The received signal is monitored in ordinary ASCII format and as audio signal, in order to investigate and exclude man-made radio interference. In order to exclude narrow band interference and calculate the spectral indices of the observed events, a second monitoring station, working at 36 MHz, is under construction at the village of Nikiforos near the town of Drama, about 130 km away of Thessaloniki. Finally, we plan to construct a third monitoring station at 58 MHz, in Thessaloniki. This frequency was revealed to be relatively free of interference, after a thorough investigation of the region.

  11. Radio spectra of pulsars. Pt. 1

    International Nuclear Information System (INIS)

    Izekova, V.A.; Kuzmin, A.D.; Malofeev, V.M.; Shitov, Yu.P.

    1981-01-01

    The results of flux pulsar radioemission measurements at meter wavelength, made at Pushchino Radio Astronomical Observatory of the Lebedev Physical Institute, are presented. Flux densities at 102, 85, 61 and 39 MHz have been measured for 85, 29, 37 and 23 pulsars correspondingly. Some of them were performed at all frequencies simultaneously. On the basis of these data and high frequencies data obtained by other authors, spectra of 52 pulsars were plotted. In practically all investigated pulsars we have detected a turn-over frequency at which the flux density of pulsar radioemission attained its maximum. Its mean value is vsub(m) = 130 +- 80 MHz. Averaged on many pulsars, the spectral index is negative in the 39-61 MHz frequency range (anti ALPHA 39 sub(-) 61 = -1.4 +- 0.4) and passes through zero at frequencies of about 100 MHz, becoming positive in the 100-400 MHz frequency range. It was noticed that the spectral index in the 100-400 MHz interval depends upon such pulsar periods as α 100 sub(-) 400 = 0.7 log p + 0.9. Using the spectra, more precise radio luminosities of pulsars have been computed. (orig.)

  12. Probing ionospheric structures using the LOFAR radio telescope

    NARCIS (Netherlands)

    Mevius, M.; van der Tol, S.; Pandey, V.N.; Vedantham, H. K.; Brentjens, M. A.; Bruyn, A. G.; Abdalla, F. B.; Asad, K. M. B.; Bregman, J. D.; Brouw, W. N.; Bus, S.; Chapman, E.; Ciardi, B.; Fernandez, E. R.; Ghosh, A.; Harker, G.; Iliev, I. T.; Jelic, Vibor; Kazemi, S.; Koopmans, L. V. E.; Noordam, J. E.; Offringa, A. R.; Patil, A. H.; Weeren, R. J.; Wijnholds, S.; Yatawatta, S.; Zaroubi, S.

    2016-01-01

    LOFAR is the LOw-Frequency Radio interferometer ARray located at midlatitude (52°53'N). Here we present results on ionospheric structures derived from 29 LOFAR nighttime observations during the winters of 2012/2013 and 2013/2014. We show that LOFAR is able to determine differential ionospheric total

  13. Interpreting behavioural data from Radio-Acoustic Positioning ...

    African Journals Online (AJOL)

    To detect behavioural patterns of individually tagged squid Loligo vulgaris reynaudii in a Radio-Acoustic Positioning Telemetry (RAPT) buoy array, trajectories reflecting the four dimensions of latitude, longitude, depth and time were plotted from data collected during field experiments in South Africa. Finding a continuous ...

  14. Adaptive ground implemented phase array

    Science.gov (United States)

    Spearing, R. E.

    1973-01-01

    The simulation of an adaptive ground implemented phased array of five antenna elements is reported for a very high frequency system design that is tolerant to the radio frequency interference environment encountered by a tracking data relay satellite. Signals originating from satellites are received by the VHF ring array and both horizontal and vertical polarizations from each of the five elements are multiplexed and transmitted down to ground station. A panel on the transmitting end of the simulation chamber contains up to 10 S-band RFI sources along with the desired signal to simulate the dynamic relationship between user and TDRS. The 10 input channels are summed, and desired and interference signals are separated and corrected until the resultant sum signal-to-interference ratio is maximized. Testing performed with this simulation equipment demonstrates good correlation between predicted and actual results.

  15. Unlocking radio broadcasts

    DEFF Research Database (Denmark)

    Skov, Mette; Lykke, Marianne

    2012-01-01

    This poster reports the preliminary results of a user study uncovering the information seeking behaviour of humanities scholars dedicated to radio research. The study is part of an interdisciplinary research project on radio culture and auditory resources. The purpose of the study is to inform...... the design of information architecture and interaction design of a research infrastructure that will enable future radio and audio based research. Results from a questionnaire survey on humanities scholars‟ research interest and information needs, preferred access points, and indexing levels are reported....... Finally, a flexible metadata schema is suggested, that includes both general metadata and highly media and research project specific metadata....

  16. Radio y elecciones

    Directory of Open Access Journals (Sweden)

    Alma Rosa Alva de la Selva

    2000-01-01

    Full Text Available En este trabajo se analiza el comportamiento de la radio en México ante la contienda electoral de julio de 2000. Se examina el papel de la radio como espacio para la discusión política, así como el tratamiento informativo que hizo del tema. Asimismo, se analiza la posible repercusión de factores de reciente surgimiento en el panorama radiofónico para un manejo más autónomo de la información política en la radio

  17. Astronomical Data Integration Beyond the Virtual Observatory

    Science.gov (United States)

    Lemson, G.; Laurino, O.

    2015-09-01

    "Data integration" generally refers to the process of combining data from different source data bases into a unified view. Much work has been devoted in this area by the International Virtual Observatory Alliance (IVOA), allowing users to discover and access databases through standard protocols. However, different archives present their data through their own schemas and users must still select, filter, and combine data for each archive individually. An important reason for this is that the creation of common data models that satisfy all sub-disciplines is fraught with difficulties. Furthermore it requires a substantial amount of work for data providers to present their data according to some standard representation. We will argue that existing standards allow us to build a data integration framework that works around these problems. The particular framework requires the implementation of the IVOA Table Access Protocol (TAP) only. It uses the newly developed VO data modelling language (VO-DML) specification, which allows one to define extensible object-oriented data models using a subset of UML concepts through a simple XML serialization language. A rich mapping language allows one to describe how instances of VO-DML data models are represented by the TAP service, bridging the possible mismatch between a local archive's schema and some agreed-upon representation of the astronomical domain. In this so called local-as-view approach to data integration, “mediators" use the mapping prescriptions to translate queries phrased in terms of the common schema to the underlying TAP service. This mapping language has a graphical representation, which we expose through a web based graphical “drag-and-drop-and-connect" interface. This service allows any user to map the holdings of any TAP service to the data model(s) of choice. The mappings are defined and stored outside of the data sources themselves, which allows the interface to be used in a kind of crowd-sourcing effort

  18. SPHEREx: Science Opportunities for the Astronomical Community

    Science.gov (United States)

    Cooray, Asantha; SPHEREx Science Team

    2018-01-01

    SPHEREx, a mission in NASA's Medium Explorer (MIDEX) program that was selected for Phase A study in August 2017, will perform an all-sky near-infrared spectral survey between 0.75 - 5.0 microns. The survey will reach 18.3 AB mag (5 sigma) in R=41 filters, with R=135 coverage between 4.2 - 5.0 microns. The key science topics of the SPHEREx team are: (a) primordial non-Gaussianity through 3-dimensional galaxy clustering; (b) extragalactic background light fluctuations; and (c) ices and biogenic molecules in the interstellar medium and towards protoplanetary environments.The large legacy dataset of SPHEREx will enable a large number of scientific studies and find interesting targets for follow-up observations with Hubble, JWST, ALMA, among other facilities. The SPHEREx catalog will include 1.4 billion galaxies, with redshifts secured for more than 10 and 120 million with fractional accuracies in error/(1+z) better than 0.3% and 3%, respectively. The spectral coverage and resolution provided by SPHEREx are adequate to determine redshifts for most WISE-detected sources with an accuracy better than 3%. The catalog will contain close to 1.5 million quasars including 300 bright QSOs at z > 7 during the epoch of reionization, based on observational extrapolations. The catalog will be adequate to obtain redshifts for all 25,000 galaxy clusters expected to be detected in X-rays with e-Rosita. SPHEREx produces all-sky maps of the Galactic emission lines, including hydrocarbon emission around 3 microns.In this poster, we will show example science studies the broader astronomical community will be able to lead using the SPHEREx database. We will also outline existing plans within the SPHEREx team to develop software tools to enable easy access to the data and to conduct catalog searches, and ways in which the community can provide input to the SPHEREx Science Team on scientific studies and data/software requirements for those studies. The team is eager to develop best software

  19. RADIO TRANSIENTS FROM ACCRETION-INDUCED COLLAPSE OF WHITE DWARFS

    International Nuclear Information System (INIS)

    Moriya, Takashi J.

    2016-01-01

    We investigate observational properties of accretion-induced collapse (AIC) of white dwarfs (WDs) in radio frequencies. If AIC is triggered by accretion from a companion star, a dense circumstellar medium can be formed around the progenitor system. Then, the ejecta from AIC collide with the dense circumstellar medium, creating a strong shock. The strong shock can produce synchrotron emission that can be observed in radio frequencies. Even if AIC occurs as a result of WD mergers, we argue that AIC may cause fast radio bursts (FRBs) if a certain condition is satisfied. If AIC forms neutron stars (NSs) that are so massive that rotation is required to support themselves (i.e., supramassive NSs), the supramassive NSs may immediately lose their rotational energy by the r-mode instability and collapse to black holes. If the collapsing supramassive NSs are strongly magnetized, they may emit FRBs, as previously proposed. The AIC radio transients from single-degenerate systems may be detected in future radio transient surveys like the Very Large Array Sky Survey or the Square Kilometer Array transient survey. Because AIC has been proposed as a source of gravitational waves (GWs), GWs from AIC may be accompanied by radio-bright transients that can be used to confirm the AIC origin of observed GWs.

  20. RADIO TRANSIENTS FROM ACCRETION-INDUCED COLLAPSE OF WHITE DWARFS

    Energy Technology Data Exchange (ETDEWEB)

    Moriya, Takashi J., E-mail: takashi.moriya@nao.ac.jp [Division of Theoretical Astronomy, National Astronomical Observatory of Japan, National Institutes of Natural Sciences, 2-21-1 Osawa, Mitaka, Tokyo 181-8588 (Japan)

    2016-10-20

    We investigate observational properties of accretion-induced collapse (AIC) of white dwarfs (WDs) in radio frequencies. If AIC is triggered by accretion from a companion star, a dense circumstellar medium can be formed around the progenitor system. Then, the ejecta from AIC collide with the dense circumstellar medium, creating a strong shock. The strong shock can produce synchrotron emission that can be observed in radio frequencies. Even if AIC occurs as a result of WD mergers, we argue that AIC may cause fast radio bursts (FRBs) if a certain condition is satisfied. If AIC forms neutron stars (NSs) that are so massive that rotation is required to support themselves (i.e., supramassive NSs), the supramassive NSs may immediately lose their rotational energy by the r-mode instability and collapse to black holes. If the collapsing supramassive NSs are strongly magnetized, they may emit FRBs, as previously proposed. The AIC radio transients from single-degenerate systems may be detected in future radio transient surveys like the Very Large Array Sky Survey or the Square Kilometer Array transient survey. Because AIC has been proposed as a source of gravitational waves (GWs), GWs from AIC may be accompanied by radio-bright transients that can be used to confirm the AIC origin of observed GWs.