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  • richardmitnick 8:29 am on August 28, 2014 Permalink | Reply
    Tags: , , , , National Radio Astronomy Observatory (NRAO)   

    From NRAO: “Orion Rocks! Pebble-Size Particles May Jump-Start Planet Formation” 

    NRAO Icon
    National Radio Astronomy Observatory

    NRAO Banner

    August 27, 2014

    Rocky planets like Earth start out as microscopic bits of dust tinier than a grain of sand, or so theories predict.

    Astronomers using the National Science Foundation’s (NSF) Green Bank Telescope (GBT) have discovered that filaments of star-forming gas near the Orion Nebula may be brimming with pebble-size particles — planetary building blocks 100 to 1,000 times larger than the dust grains typically found around protostars. If confirmed, these dense ribbons of rocky material may well represent a new, mid-size class of interstellar particles that could help jump-start planet formation.

    orion
    Radio/optical composite of the Orion Molecular Cloud Complex showing the OMC-2/3 star-forming filament. GBT data is shown in orange. Uncommonly large dust grains there may kick-start planet formation. Credit: S. Schnee, et al.; B. Saxton, B. Kent (NRAO/AUI/NSF); We acknowledge the use of NASA’s SkyView Facility located at NASA Goddard Space Flight Center.

    “The large dust grains seen by the GBT would suggest that at least some protostars may arise in a more nurturing environment for planets,” said Scott Schnee, an astronomer with the National Radio Astronomy Observatory (NRAO) in Charlottesville, Virginia. “After all, if you want to build a house, it’s best to start with bricks rather than gravel, and something similar can be said for planet formation.”

    The new GBT observations extend across the northern portion of the Orion Molecular Cloud Complex [above], a star-forming region that includes the famed Orion Nebula. The star-forming material in the section studied by the GBT, called OMC-2/3, has condensed into long, dust-rich filaments. The filaments are dotted with many dense knots known as cores. Some of the cores are just starting to coalesce while others have begun to form protostars — the first early concentrations of dust and gas along the path to star formation. Astronomers speculate that in the next 100,000 to 1 million years, this area will likely evolve into a new star cluster. The OMC-2/3 region is located approximately 1,500 light-years from Earth and is roughly 10 light-years long.

    Based on earlier maps of this region made with the IRAM 30 meter radio telescope in Spain, the astronomers expected to find a certain brightness to the dust emission when they observed the filaments at slightly longer wavelengths with the GBT.

    iram
    IRAM 30m Telescope

    Instead, the GBT discovered that the area was shining much brighter than expected in millimeter-wavelength light.

    “This means that the material in this region has different properties than would be expected for normal interstellar dust,” noted Schnee. “In particular, since the particles are more efficient than expected at emitting at millimeter wavelengths, the grains are very likely to be at least a millimeter, and possibly as large as a centimeter across, or roughly the size of a small Lego-style building block.”

    Though incredibly small compared to even the most modest of asteroids, dust grains on the order of a few millimeters to a centimeter are incredibly large for such young star-forming regions. Due to the unique environment in the Orion Molecular Cloud Complex, the researchers propose two intriguing theories for their origin.

    The first is that the filaments themselves helped the dust grains grow to such unusual proportions. These regions, compared to molecular clouds in general, have lower temperatures, higher densities, and lower velocities — all of which would encourage grain growth.

    The second scenario is that the rocky particles originally grew inside a previous generation of cores or perhaps even protoplanetary disks. The material could then have escaped back into the surrounding molecular cloud rather than becoming part of the original newly forming star system.

    “Rather than typical interstellar dust, these researchers appear to have detected vast streamers of gravel — essentially a long and winding road in space,” said NRAO astronomer Jay Lockman, who was not involved in these observations. “We’ve known about dust specks and we have known that there are things the size of asteroids and planets, but if we can confirm these results it would add a new population of rocky particles to interstellar space.”

    The most recent data were taken with the Green Bank Telescope’s high frequency imaging camera, MUSTANG. These data were compared with earlier studies as well as temperature estimates obtain from observations of ammonia molecules in the clouds.

    “Though our results suggest the presence of unexpectedly large dust grains, measuring the mass of dust is not a straightforward process and there could be other explanations for the bright signature we detected in the emission from the Orion Molecular Cloud,” concluded Brian Mason, an astronomer at the NRAO and co-author on the paper. “Our team continues to study this fascinating area. Since it contains one of the highest concentrations of protostars of any nearby molecular cloud it will continue to excite the curiosity of astronomers.”

    A paper detailing these results is accepted for publication in the Monthly Notices of the Royal Astronomical Society.

    See the full article here.

    Another view, this from Hubble

    NASA Hubble Telescope
    NASA/ESA Hubble

    orion2

    In one of the most detailed astronomical images ever produced, NASA/ESA’s Hubble Space Telescope captured an unprecedented look at the Orion Nebula. … This extensive study took 105 Hubble orbits to complete. All imaging instruments aboard the telescope were used simultaneously to study Orion. The Advanced Camera mosaic covers approximately the apparent angular size of the full moon.

    The NRAO operates a complementary, state-of-the-art suite of radio telescope facilities for use by the scientific community, regardless of institutional or national affiliation: the Very Large Array (VLA), the Robert C. Byrd Green Bank Telescope (GBT), and the Very Long Baseline Array (VLBA)*.

    NRAO ALMA
    NRAO ALMA

    NRAO GBT
    NRAO GBT

    NRAO VLA
    NRAO VLA

    The NRAO is building two new major research facilities in partnership with the international community that will soon open new scientific frontiers: the Atacama Large Millimeter/submillimeter Array (ALMA), and the Expanded Very Large Array (EVLA). Access to ALMA observing time by the North American astronomical community will be through the North American ALMA Science Center (NAASC).
    *The Very Long Baseline Array (VLBA) comprises ten radio telescopes spanning 5,351 miles. It’s the world’s largest, sharpest, dedicated telescope array. With an eye this sharp, you could be in Los Angeles and clearly read a street sign in New York City!

    Astronomers use the continent-sized VLBA to zoom in on objects that shine brightly in radio waves, long-wavelength light that’s well below infrared on the spectrum. They observe blazars, quasars, black holes, and stars in every stage of the stellar life cycle. They plot pulsars, exoplanets, and masers, and track asteroids and planets.

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  • richardmitnick 3:42 pm on August 25, 2014 Permalink | Reply
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    From ESO: “New ALMA Equipment Designed in Chile” 


    European Southern Observatory

    25 August 2014
    Richard Hook
    ESO, Public Information Officer
    Garching bei München, Germany
    Tel: +49 89 3200 6655
    Cell: +49 151 1537 3591
    Email: rhook@eso.org

    ALMA Array
    ALMA Array

    New equipment for transporting one of the most sensitive components of the ALMA array — the antenna Front Ends (cryogenic refrigerators) — has been delivered to ALMA by the National Radio Astronomy Observatory (NRAO), the North American associate of the Atacama Large Millimeter/submillimeter Array. This new vehicle, which will save lots of time and increase safety during manoeuvers, was completely designed and built in Chile. It is the first shipment of one of four vehicles for handling the Front Ends that hold the set of detectors inside ALMA´s antennas, and is part of the technological exchange policy with the host country.

    set3

    The Front End Handling Vehicle (FEHV) — a robust elevator-crane car — is the result of a three year design and manufacturing collaboration between NRAO and a team of Chilean professionals from the Prolaser and Maestranza Walper companies, located in the city of Valdivia in the south of Chile. The main tourist attractions of this region inspired the names of each of these four vehicles, being the first one called after a river: Calle-Calle.

    The FEHV will help to shorten the time needed to set up and remove the receivers from the antennas. “This replacement job takes place every five days. Over the 30 year lifetime projected for the observatory using this vehicle will save a huge amount of resources, considering that this specific task takes 2000 person hours a year, approximately”, proudly stated Rodrigo Brito, team leader supervising the official shipment of the manufacturing contribution from the North American partner of ALMA.

    Each cryostat, together with the receivers comprising each Front End, costs about one million dollars, weighs around 750 kilogrammes and must be lifted up almost two metres to be positioned precisely in the confined space inside the antennas cubicles. The FEHV has a built-in platform to lift its load in a safe way, move it and rotate it for perfect alignment during the setup. It weighs 709 kilogrammes and is 2.20 metres long, 1.05 metres wide and 1.50 metres tall.

    See the full article here.

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    ESO, European Southern Observatory, builds and operates a suite of the world’s most advanced ground-based astronomical telescopes.

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  • richardmitnick 4:19 pm on August 11, 2014 Permalink | Reply
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    From NASA/Goddard: “NASA’s 3-D Study of Comets Reveals Chemical Factory at Work” 

    NASA Goddard Banner

    NASA Goddard Space flight Center

    August 11, 2014
    Elizabeth Zubritsky
    NASA’s Goddard Space Flight Center, Greenbelt, Maryland
    301-614-5438
    elizabeth.a.zubritsky@nasa.gov

    Nancy Neal-Jones
    NASA’s Goddard Space Flight Center, Greenbelt, Maryland
    301-286-0039
    nancy.n.jones@nasa.gov

    A NASA-led team of scientists has created detailed 3-D maps of the atmospheres surrounding comets, identifying several gases and mapping their spread at the highest resolution ever achieved.

    “We achieved truly first-of-a-kind mapping of important molecules that help us understand the nature of comets,” said Martin Cordiner, a researcher working in the Goddard Center for Astrobiology at NASA’s Goddard Space Flight Center in Greenbelt, Maryland. Cordiner led the international team of researchers.

    Almost unheard of for comet studies, the 3-D perspective provides deeper insight into which materials are shed from the nucleus of the comet and which are produced within the atmosphere, or coma. This helped the team nail down the sources of two key organic, or carbon-containing, molecules.

    The observations were conducted in 2013 on comets Lemmon and ISON using the Atacama Large Millimeter/submillimeter Array, or ALMA, a network of high-precision antennas in Chile. These comets are the first to be studied with ALMA.

    ALMA Array
    ALMA

    The ALMA observations combine a high-resolution 2-D image of a comet’s gases with a detailed spectrum at each point. From these spectra, researchers can identify the molecules present at every point and determine their velocities (speed plus direction) along the line-of-sight; this information provides the third dimension – the depth of the coma.

    “So, not only does ALMA let us identify individual molecular species in the coma, it also gives us the ability to map their locations with great sensitivity,” said Anthony Remijan, a scientist with the National Radio Astronomy Observatory, one of the organizations that operates ALMA, and a co-author of the study.

    The researchers reported results for three molecular species, focusing primarily on two whose sources have been difficult to discern (except in comet Halley). The 3-D maps indicated whether each molecule was flowing outward evenly in all directions or coming off in jets or in clumps.

    In each comet, the team found that two species – formaldehyde and HNC (made of one hydrogen, one nitrogen and one carbon) – were produced in the coma. For formaldehyde, this confirmed what researchers already suspected, but the new maps contained enough detail to resolve clumps of the material moving into different regions of the coma day-by-day and even hour-by-hour.

    For HNC, the maps settled a long-standing question about the material’s source. Initially, HNC was thought to be pristine interstellar material coming from the nucleus of a comet, whereas later work suggested other possible sources. The new study provided the first proof that HNC is produced during the breakdown of large molecules or organic dust in the coma.

    “Understanding organic dust is important, because such materials are more resistant to destruction during atmospheric entry, and some could have been delivered intact to early Earth, thereby fueling the emergence of life,” said Michael Mumma, Director of the Goddard Center for Astrobiology, and a co-author on the study. “These observations open a new window on this poorly known component of cometary organics.”

    The observations, published today by the Astrophysical Journal Letters, also were significant because modest comets like Lemmon and ISON contain relatively low concentrations of crucial molecules, making them difficult to probe in depth with Earth-based telescopes. The few comprehensive studies of this kind so far have been conducted on bright, blockbuster comets, such as Hale-Bopp. The present results extend them to comets of only moderate brightness.

    This research was funded by the NASA Astrobiology Institute through the Goddard Center for Astrobiology and by NASA’s Planetary Atmospheres and Planetary Astronomy programs. ALMA is an international astronomy facility. Its construction and operations are led on behalf of Europe by the European Southern Observatory, on behalf of North America by the U.S. National Radio Astronomy Observatory (NRAO) and on behalf of East Asia by the National Astronomical Observatory of Japan.

    See the full article here.

    NASA’s Goddard Space Flight Center is home to the nation’s largest organization of combined scientists, engineers and technologists that build spacecraft, instruments and new technology to study the Earth, the sun, our solar system, and the universe.

    Named for American rocketry pioneer Dr. Robert H. Goddard, the center was established in 1959 as NASA’s first space flight complex. Goddard and its several facilities are critical in carrying out NASA’s missions of space exploration and scientific discovery.

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  • richardmitnick 3:24 pm on August 5, 2014 Permalink | Reply
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    From NRAO: “ALMA Pinpoints Pluto to Help Guide NASA’s New Horizons Spacecraft” 

    NRAO Icon
    National Radio Astronomy Observatory

    NRAO Banner

    August 5, 2014
    Charles Blue, NRAO Public Information Officer
    (434) 296-0314; cblue@nrao.edu

    Astronomers using the Atacama Large Millimeter/submillimeter Array (ALMA) are making high-precision measurements of Pluto’s location and orbit around the Sun to help NASA’s New Horizons spacecraft accurately home in on its target when it nears Pluto and its five known moons in July 2015.

    ALMA Array
    ALMA

    NASA New Horizons spacecraft
    NASA/New Horizons

    Though observed for decades with ever-larger optical telescopes on Earth and in space, astronomers are still working out Pluto’s exact position and path around our Solar System. This lingering uncertainty is due to Pluto’s extreme distance from the Sun (approximately 40 times farther out than the Earth) and the fact that we have been studying it for only about one-third of its orbit. Pluto was discovered in 1930 and takes 248 years to complete one revolution around the Sun.

    “With these limited observational data, our knowledge of Pluto’s position could be wrong by several thousand kilometers, which compromises our ability to calculate efficient targeting maneuvers for the New Horizons spacecraft,” said New Horizons Project Scientist Hal Weaver, from the Johns Hopkins University Applied Physics Laboratory in Laurel, Maryland.

    The New Horizons team made use of the ALMA positioning data, together with newly analyzed visible light measurements stretching back to Pluto’s discovery, to determine how to perform the first such scheduled course correction for targeting, known as a Trajectory Correction Maneuver (TCM), in July. This maneuver helped ensure that New Horizons uses the minimum fuel to reach Pluto, saving as much as possible for a potential extended mission to explore Kuiper Belt objects after the Pluto system flyby is complete.

    kuiper
    Kuiper Belt

    To prepare for this first TCM, astronomers needed to pinpoint Pluto’s position using the most distant and most stable reference points possible. Finding such a reference point to accurately calculate trajectories of such small objects at such vast distances is incredibly challenging. Normally, stars at great distances are used by optical telescopes for astrometry (the positioning of things on the sky) since they change position only slightly over many years. For New Horizons, however, even more precise measurements were necessary to ensure its encounter with Pluto would be as on-target as possible.

    The most distant and most apparently stable objects in the Universe are quasars, galaxies more than 10 billion light-years away. Though quasars appear very dim to optical telescopes, they are incredibly bright at radio wavelengths, particularly the millimeter wavelengths that ALMA can see.

    “The ALMA astrometry used a bright quasar named J1911-2006 with the goal to cut in half the uncertainty of Pluto’s position,” said Ed Fomalont, an astronomer with the National Radio Astronomy Observatory in Charlottesville, Virginia, and currently assigned to ALMA’s Operations Support Facility in Chile.

    ALMA was able to study Pluto and its largest moon Charon by picking up the radio emission from their cold surfaces, which are about 43 degrees Kelvin (-230 degrees Celsius).

    The team first observed these two icy worlds in November 2013, and then three more times in 2014 — once in April and twice in July. Additional observations are scheduled for October 2014.

    “By taking multiple observations at different dates, we allow Earth to move along its orbit, offering different vantage points in relation to the Sun,” said Fomalont. “Astronomers can then better determine Pluto’s distance and orbit.” This astronomical technique is called measuring Pluto’s parallax.

    “We are very excited about the state-of-the-art capabilities that ALMA brings to bear to help us better target our historic exploration of the Pluto system,” said New Horizons Principal Investigator Alan Stern of the Southwest Research Institute in Boulder, Colorado. “We thank the entire ALMA team for their support and for the beautiful data they are gathering for New Horizons.”

    The National Radio Astronomy Observatory is a facility of the National Science Foundation, operated under cooperative agreement by Associated Universities, Inc.

    ALMA, an international astronomy facility, is a partnership of Europe, North America and East Asia in cooperation with the Republic of Chile. ALMA construction and operations are led on behalf of Europe by the European Southern Observatory (ESO), on behalf of North America by the National Radio Astronomy Observatory (NRAO), and on behalf of East Asia by the National Astronomical Observatory of Japan (NAOJ). The Joint ALMA Observatory (JAO) provides the unified leadership and management of the construction, commissioning and operation of ALMA.

    New Horizons is the first mission to the Pluto system and the Kuiper Belt of rocky, icy objects beyond. The Johns Hopkins University Applied Physics Laboratory (APL) manages the mission for NASA’s Science Mission Directorate; Alan Stern, of the Southwest Research Institute (SwRI), is the principal investigator and leads the mission. SwRI leads the science team, payload operations and encounter science planning; APL designed, built and operates the New Horizons spacecraft. New Horizons is part of the New Frontiers Program managed by NASA’s Marshall Space Flight Center in Huntsville, Ala. For more information, visit http://pluto.jhuapl.edu.

    See the full article here.

    The NRAO operates a complementary, state-of-the-art suite of radio telescope facilities for use by the scientific community, regardless of institutional or national affiliation: the Very Large Array (VLA), the Robert C. Byrd Green Bank Telescope (GBT), and the Very Long Baseline Array (VLBA)*.

    NRAO ALMA
    NRAO ALMA

    NRAO GBT
    NRAO GBT

    NRAO VLA
    NRAO VLA

    The NRAO is building two new major research facilities in partnership with the international community that will soon open new scientific frontiers: the Atacama Large Millimeter/submillimeter Array (ALMA), and the Expanded Very Large Array (EVLA). Access to ALMA observing time by the North American astronomical community will be through the North American ALMA Science Center (NAASC).
    *The Very Long Baseline Array (VLBA) comprises ten radio telescopes spanning 5,351 miles. It’s the world’s largest, sharpest, dedicated telescope array. With an eye this sharp, you could be in Los Angeles and clearly read a street sign in New York City!

    Astronomers use the continent-sized VLBA to zoom in on objects that shine brightly in radio waves, long-wavelength light that’s well below infrared on the spectrum. They observe blazars, quasars, black holes, and stars in every stage of the stellar life cycle. They plot pulsars, exoplanets, and masers, and track asteroids and planets.

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  • richardmitnick 3:21 pm on July 17, 2014 Permalink | Reply
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    From NRAO: “ALMA Upgrade to Supercharge Event Horizon Telescope, Astronomy’s ‘Killer App’” 

    NRAO Icon

    National Radio Astronomy Observatory

    NRAO Banner

    June 4, 2014

    Contact: Charles Blue
    cblue@nrao.edu
    (434) 296-0314

    Scientists recently upgraded the Atacama Large Millimeter/submillimeter Array (ALMA) by installing an ultraprecise atomic clock at ALMA’s Array Operations Site, home to the observatory’s supercomputing correlator. This upgrade will eventually allow ALMA to synchronize with a worldwide network of radio astronomy facilities collectively known as the Event Horizon Telescope (EHT).

    Once assembled, the EHT — with ALMA as the largest and most sensitive site — will form an Earth-sized telescope with the magnifying power required to see details at the edge of the supermassive black hole at the center of the Milky Way.

    ALMA Array
    Before ALMA can lend its unmatched capabilities to this and similar scientific observations, however, it must first transform into a different kind of instrument known as a phased array. This new version of ALMA will allow its 66 antennas to function as a single radio dish 85 meters in diameter. It’s this unified power coupled with ultraprecise timekeeping that will allow ALMA to link with other observatories.

    A major milestone along this path was achieved recently when the science team performed what could be considered a “heart transplant” on the telescope by installing a custom-built atomic clock powered by a hydrogen maser. This new timepiece uses a process similar to a laser to amplify a single pure tone, cycles of which are counted to produce a highly accurate ‘tick’.

    ALMA’s original time reference, a clock based on rubidium gas, will be retired and used as a spare after the maser is completely integrated with ALMA’s electronics.

    Shep Doeleman, the principal investigator of the ALMA Phasing Project and assistant director of the Massachusetts Institute of Technology’s Haystack Observatory, participated during the maser installation via remote video link. “Once the phasing is complete, ALMA will use the ultraprecise ticking of this new atomic clock to join the aptly named Event Horizon Telescope as the most sensitive participating site, increasing sensitivity by a factor of 10,” he said.

    Expanding the Frontiers of Astronomy

    Supermassive black holes lurk at the center of all galaxies and contain millions or even billions of times the mass of our Sun. These space-bending behemoths are so massive that nothing, not even light, can escape their gravitational influence. Understanding how a black hole devours matter, powers jets of particles and energy, and distorts space and time are leading challenges in astronomy and physics.

    The black hole at the center of the Milky Way is a 4 million solar mass giant located approximately 26,000 light-years from Earth in the direction of the constellation Sagittarius. It is shrouded from optical telescopes by dense clouds of dust and gas, which is why observatories like ALMA, which operate at the longer millimeter and submillimeter wavelengths, are essential to study its properties.

    Supermassive black holes can be relatively tranquil or they can flare up and drive incredibly powerful jets of subatomic particles deep into intergalactic space; quasars seen in the very early Universe are an extreme example. The fuel for these jets comes from in-falling material, which becomes superheated as it spirals inward. Astronomers hope to capture our Galaxy’s central black hole in the process of actively feeding to better understand how black holes affect the evolution of our Universe and how they shape the development of stars and galaxies.

    A phased ALMA will arrive just in time to observe a highly anticipated cosmic event, the collision of a giant cloud of dust and gas known as G2 with our Galaxy’s central supermassive black hole. It is speculated that this collision may awaken this sleeping giant, generating extreme energy and possibly fueling a jet of subatomic particles, a highly unusual feature in a mature spiral galaxy like the Milky Way. The collision is predicted to begin in 2014 and will likely continue for more than a year.

    High resolution imaging of the event horizon also could improve our understanding of how the highly ordered Universe as described by [Albert]Einstein meshes with the messy and chaotic cosmos of quantum mechanics – two systems for describing the physical world that are woefully incompatible on the smallest of scales.

    Other independent research will target molecules in space to determine whether or not the fundamental constants of nature have changed over cosmic time.

    Shadowy Science

    The light-bending power of black holes also presents a unique opportunity to observe the so-called “shadow” of a black hole. Light near the event horizon of a black hole does not travel in a straight line, but instead takes on weird hyperbolic trajectories and can even achieve a stable orbit. Some of this light, which begins its journey traveling away from observers on Earth, can get twisted back around, warping in such a way that it takes a 180 degree turn. This would allow scientists to study the far-side of a black hole and actually see its shadow in space. Since the size and shape of this shadow depends on the mass and spin of black hole, these observations could tell us much about how space and time are warped in this extreme environment.

    Calculations indicate a resolution of 50 micro-arcseconds (approximately 2,000 times finer than the Hubble Space Telescope) is needed to image the shadow effect. That’s equivalent to reading the date on a quarter at the distance from New York to Los Angeles. This amazing high-resolution imaging is within the reach of the ALMA-enabled Event Horizon Telescope.

    Development Timeline and Funding

    Initial planning for a Phased ALMA Array began in 2008, propelled by the objective of imaging a black hole and other previously unattainable science. The requirements necessary to phase the ALMA array were shared early on with the ALMA design team so the implementation plan would not affect ALMA construction or operations.

    The Phased ALMA Array is funded primarily by the U.S. National Science Foundation. Additional funding is provided through North American contributions to the ALMA Development Fund and international cost sharing through the Academia Sinica Institute of Astronomy and Astrophysics, Max Planck Institute for Radio Astronomy, Universidad de Concepcion, the Japan Society for the Promotion of Science, and the Toray Science Foundation. Initial funding was provided in 2011. The project passed preliminary design review and was approved by the ALMA Board in 2012. The project passed Critical Design Review in 2013.

    The current goal is to test the first combined signal of a phased ALMA and another telescope in 2014, and to undergo full commissioning and be ready for full observations in 2015.

    Technology and Engineering

    ALMA was designed to work as an interferometer – a telescope made up of many individual elements. Each antenna pair creates a single baseline. ALMA can produce as many as 1,291 baselines, some up to 16 kilometers long.

    The phased array, however, operates differently. The signals from all the antennas are simply added together. To do this, specialized electronics and computer equipment are being built at the National Radio Astronomy Observatory’s Central Development Lab in Charlottesville, Virginia. These new circuit boards will be installed into ALMA’s correlator, the supercomputer that combines the signals from the antennas.

    The signal from the phased array will then be time-stamped and encoded by a dedicated atomic clock – the new hydrogen maser procured and tested by MIT’s Haystack Observatory — which will allow the data to be shipped to a central processing center where it will be combined with identically timed signals from other telescopes.

    The high-speed recorders that will capture the torrent of data flowing from the ALMA phased array were designed by the MIT Haystack Observatory. Software to run the new phasing system is being developed by multiple institutions involved in the phasing project.

    Event Horizon Telescope

    The Event Horizon Telescope (EHT) derives its extreme magnifying power from connecting widely spaced radio dishes across the globe into an Earth-sized virtual telescope. This technique, called Very Long Baseline Interferometry (VLBI), is the same process that enables telescopes like the NRAO’s Very Long Baseline Array (VLBA) to achieve such amazing power and resolution. The difference between existing VLBI facilities and the EHT is the sheer geographical scope of the EHT project, its extension to the shortest observing wavelengths, and addition of the unprecedented collecting area enabled by a phased ALMA.

    “By uniting the most advanced millimeter and submillimeter wavelength radio dishes across the globe, the Event Horizon Telescope creates a fundamentally new instrument with the greatest magnifying power ever achieved,” said Doeleman. “Anchored by ALMA, the EHT will open a new window onto black hole research and bring into focus one of the only places in the Universe where Einstein’s theories may break down: at the event horizon.”

    ALMA, an international astronomy facility, is a partnership of Europe, North America and East Asia in cooperation with the Republic of Chile. ALMA construction and operations are led on behalf of Europe by ESO, on behalf of North America by the National Radio Astronomy Observatory (NRAO), and on behalf of East Asia by the National Astronomical Observatory of Japan (NAOJ). The Joint ALMA Observatory (JAO) provides the unified leadership and management of the construction, commissioning and operation of ALMA.

    The U.S. National Science Foundation (NSF) is an independent federal agency that supports fundamental research and education across all fields of science and engineering.

    See the full article here.

    The NRAO operates a complementary, state-of-the-art suite of radio telescope facilities for use by the scientific community, regardless of institutional or national affiliation: the Very Large Array (VLA), the Robert C. Byrd Green Bank Telescope (GBT), and the Very Long Baseline Array (VLBA)*.

    NRAO ALMA
    NRAO ALMA

    NRAO GBT
    NRAO GBT

    NRAO VLA
    NRAO VLA

    The NRAO is building two new major research facilities in partnership with the international community that will soon open new scientific frontiers: the Atacama Large Millimeter/submillimeter Array (ALMA), and the Expanded Very Large Array (EVLA). Access to ALMA observing time by the North American astronomical community will be through the North American ALMA Science Center (NAASC).
    *The Very Long Baseline Array (VLBA) comprises ten radio telescopes spanning 5,351 miles. It’s the world’s largest, sharpest, dedicated telescope array. With an eye this sharp, you could be in Los Angeles and clearly read a street sign in New York City!

    Astronomers use the continent-sized VLBA to zoom in on objects that shine brightly in radio waves, long-wavelength light that’s well below infrared on the spectrum. They observe blazars, quasars, black holes, and stars in every stage of the stellar life cycle. They plot pulsars, exoplanets, and masers, and track asteroids and planets.


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  • richardmitnick 2:40 pm on July 17, 2014 Permalink | Reply
    Tags: , , , , National Radio Astronomy Observatory (NRAO),   

    From NRAO: “Remarkable White Dwarf Star Possibly Coldest, Dimmest Ever Detected” 

    NRAO Icon

    National Radio Astronomy Observatory

    NRAO Banner

    National Radio Astronomy Observatory

    June 23, 2014

    A team of astronomers has identified possibly the coldest, faintest white dwarf star ever detected. This ancient stellar remnant is so cool that its carbon has crystallized, forming — in effect — an Earth-size diamond in space.

    “It’s a really remarkable object,” said David Kaplan, a professor at the University of Wisconsin-Milwaukee. “These things should be out there, but because they are so dim they are very hard to find.”

    wd
    This Hubble Space Telescope image shows Sirius A, the brightest star in our nighttime sky, along with its faint, tiny stellar companion, Sirius B. Astronomers overexposed the image of Sirius A [at centre] so that the dim Sirius B [tiny dot at lower left] could be seen. The cross-shaped diffraction spikes and concentric rings around A*, and the small ring around Sirius B, are artifacts produced within the telescope’s imaging system. The two stars revolve around each other every 50 years. Sirius A, only 8.6 light-years from Earth, is the fifth closest star system known. The image was taken with Hubble’s Wide Field Planetary Camera 2.

    Kaplan and his colleagues found this stellar gem using the National Radio Astronomy Observatory’s (NRAO) Green Bank Telescope (GBT) and Very Long Baseline Array (VLBA), as well as other observatories.

    NRAO GBT
    NRAO GBT

    vlba map
    VLBA map. VLBA locations (red) and HSA locations (blue) in the contiguous United States

    White dwarfs are the extremely dense end-states of stars like our Sun that have collapsed to form an object approximately the size of the Earth. Composed mostly of carbon and oxygen, white dwarfs slowly cool and fade over billions of years. The object in this new study is likely the same age as the Milky Way, approximately 11 billion years old.

    Pulsars are rapidly spinning neutron stars, the superdense remains of massive stars that have exploded as supernovas. As neutron stars spin, lighthouse-like beams of radio waves, streaming from the poles of its powerful magnetic field, sweep through space. When one of these beams sweeps across the Earth, radio telescopes can capture the pulse of radio waves.

    The pulsar companion to this white dwarf, dubbed PSR J2222-0137, was the first object in this system to be detected. It was found using the GBT by Jason Boyles, then a graduate student at West Virginia University in Morgantown.

    These first observations revealed that the pulsar was spinning more than 30 times each second and was gravitationally bound to a companion star, which was initially identified as either another neutron star or, more likely, an uncommonly cool white dwarf. The two were calculated to orbit each other once every 2.45 days.

    The pulsar was then observed over a two-year period with the VLBA by Adam Deller, an astronomer at the Netherlands Institute for Radio Astronomy (ASTRON). These observations pinpointed its location and distance from the Earth — approximately 900 light-years away in the direction of the constellation Aquarius. This information was critical in refining the model used to time the arrival of the pulses at the Earth with the GBT.

    By applying [Albert] Einstein’s theory of relativity, the researchers studied how the gravity of the companion warped space, causing delays in the radio signal as the pulsar passed behind it. These delayed travel times helped the researchers determine the orientation of their orbit and the individual masses of the two stars. The pulsar has a mass 1.2 times that of the Sun and the companion a mass 1.05 times that of the Sun.

    These data strongly indicated that the pulsar companion could not have been a second neutron star; the orbits were too orderly for a second supernova to have taken place.

    Knowing its location with such high precision and how bright a white dwarf should appear at that distance, the astronomers believed they should have been able to observe it in optical and infrared light.

    Remarkably, neither the Southern Astrophysical Research (SOAR) telescope in Chile nor the 10-meter Keck telescope in Hawaii was able to detect it.

    Southern Astrophysical Research Telescope
    SOAR

    Keck Observatory
    Keck

    “Our final image should show us a companion 100 times fainter than any other white dwarf orbiting a neutron star and about 10 times fainter than any known white dwarf, but we don’t see a thing,” said Bart Dunlap, a graduate student at the University of North Carolina at Chapel Hill and one of the team members. “If there’s a white dwarf there, and there almost certainly is, it must be extremely cold.”

    The researchers calculated that the white dwarf would be no more than a comparatively cool 3,000 degrees Kelvin (2,700 degrees Celsius). Our Sun at its center is about 5,000 times hotter.

    Astronomers believe that such a cool, collapsed star would be largely crystallized carbon, not unlike a diamond. Other such stars have been identified and they are theoretically not that rare, but with a low intrinsic brightness, they can be deucedly difficult to detect. Its fortuitous location in a binary system with a neutron star enabled the team to identify this one.

    A paper describing these results is published in the Astrophysical Journal.

    The National Radio Astronomy Observatory is a facility of the National Science Foundation, operated under cooperative agreement by Associated Universities, Inc.

    See the full article here.

    The NRAO operates a complementary, state-of-the-art suite of radio telescope facilities for use by the scientific community, regardless of institutional or national affiliation: the Very Large Array (VLA), the Robert C. Byrd Green Bank Telescope (GBT), and the Very Long Baseline Array (VLBA)*.

    NRAO ALMA
    NRAO ALMA

    NRAO GBT
    NRAO GBT

    NRAO VLA
    NRAO VLA

    The NRAO is building two new major research facilities in partnership with the international community that will soon open new scientific frontiers: the Atacama Large Millimeter/submillimeter Array (ALMA), and the Expanded Very Large Array (EVLA). Access to ALMA observing time by the North American astronomical community will be through the North American ALMA Science Center (NAASC).
    *The Very Long Baseline Array (VLBA) comprises ten radio telescopes spanning 5,351 miles. It’s the world’s largest, sharpest, dedicated telescope array. With an eye this sharp, you could be in Los Angeles and clearly read a street sign in New York City!

    Astronomers use the continent-sized VLBA to zoom in on objects that shine brightly in radio waves, long-wavelength light that’s well below infrared on the spectrum. They observe blazars, quasars, black holes, and stars in every stage of the stellar life cycle. They plot pulsars, exoplanets, and masers, and track asteroids and planets.


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  • richardmitnick 3:48 pm on November 19, 2013 Permalink | Reply
    Tags: , , , , National Radio Astronomy Observatory (NRAO), ,   

    From NRAO: “Birth of a Millisecond Pulsar” 

    NRAO Icon
    National Radio Astronomy Observatory

    NRAO Banner

    November 19, 2013
    F.J. Lockman

    A radio pulsar is a neutron star whose strong magnetic field accelerates particles as it rotates, gradually slowing with time. One class of pulsars, however, appears to have been re-accelerated to rotational periods of a few milli-seconds through mass transfer from a binary companion. During the transfer the accreting material is heated to a temperature such that it emits X-rays, and indeed, many low-mass X-ray binaries observed throughout the Milky Way are thought to be produced by this mechanism, which must operate over many millions of years. It is thought that the se systems go on to produce radio milli-second pulsars when accretion ends.

    Recently, however, by combining multiple satellite X-ray observations with radio-wavelength data from the Green Bank Telescope (GBT) and other telescopes worldwide, scientists have identified a neutron star in a binary system that appears sometimes as an accreting X-ray emitting neutron star, and at other times as a radio pulsar.

    NRAO GBT
    NRAO’s Green Bank Telescope

    The system is in the globular cluster M28 which hosts many radio pulsars. It was discovered using the GBT in 2006, and observed to cease radio emission for months to years at a time. Thanks to the new observations it is now understood that the actual accretion process is sporadic and may vary on time scales as short as weeks. During episodes of accretion inflowing matter disrupts particle acceleration processes in the neutron star’s magnetic field, quenching the radio emission, and causing bright, pulsed X-rays. When the accretion tapers off the pulsar’s magnetosphere can accelerate particles again, and the object appears once more as a radio pulsar.

    m28
    Messier 28

    These observations establish without question the link between radio pulsars and X- ray binaries, and will allow study of the accretion process in detail.

    Reference: A. Papitto, C. Ferrigno, E. Bozzo, N. Rea, L. Pavan, L. Burderi, M. Burgay, S. Campana, T. Di Salvo, M. Falanga, M. D. Filipović, P. C. C. Freire, J. W. T. Hessels, A. Possenti, S. M. Ransom, A. Riggio, P. Romano, J. M. Sarkissian, I. H. Stairs, L. Stella, D. F. Torres, M. H. Wieringa & G. F. Wong, Nature, 501, 517 (26 Sep 2013).

    See the full article here.

    The NRAO operates a complementary, state-of-the-art suite of radio telescope facilities for use by the scientific community, regardless of institutional or national affiliation: the Very Large Array (VLA), the Robert C. Byrd Green Bank Telescope (GBT), and the Very Long Baseline Array (VLBA)*.

    NRAO ALMA
    NRAO ALMA

    NRAO GBT
    NRAO GBT

    NRAO VLA
    NRAO VLA

    The NRAO is building two new major research facilities in partnership with the international community that will soon open new scientific frontiers: the Atacama Large Millimeter/submillimeter Array (ALMA), and the Expanded Very Large Array (EVLA). Access to ALMA observing time by the North American astronomical community will be through the North American ALMA Science Center (NAASC).
    *The Very Long Baseline Array (VLBA) comprises ten radio telescopes spanning 5,351 miles. It’s the world’s largest, sharpest, dedicated telescope array. With an eye this sharp, you could be in Los Angeles and clearly read a street sign in New York City!

    Astronomers use the continent-sized VLBA to zoom in on objects that shine brightly in radio waves, long-wavelength light that’s well below infrared on the spectrum. They observe blazars, quasars, black holes, and stars in every stage of the stellar life cycle. They plot pulsars, exoplanets, and masers, and track asteroids and planets.

     
  • richardmitnick 6:28 pm on October 4, 2013 Permalink | Reply
    Tags: , , , , National Radio Astronomy Observatory (NRAO)   

    From NRAO: “Beyond The Visible: The Story of the Very Large Array” 

    NRAO Icon
    National Radio Astronomy Observatory

    NRAO Banner

    A Wonderful new video from NRAO

    Created in 2013 as the new interpretive film for the National Radio Astronomy Observatory’s Karl G. Jansky Very Large Array (VLA) public Visitor Center, this 24-minute production explores the synergies of technology and human curiosity that power the world’s most productive radio telescope. Narrated by Academy Award-winning actress Jodie Foster (star of the film “Contact,” which was based on the novel by Carl Sagan and filmed at the VLA), the program depicts many of the people whose diverse efforts enable the VLA to be a cutting-edge resource for astronomers and humanity worldwide.

    For more information about the VLA, where we welcome visitors at no charge, visit public.nrao.edu. The National Radio Astronomy Observatory (NRAO) is a facility of the National Science Foundation operated under cooperative agreement by Associated Universities, IncSee the full article here.

    The NRAO operates a complementary, state-of-the-art suite of radio telescope facilities for use by the scientific community, regardless of institutional or national affiliation: the Very Large Array (VLA), the Robert C. Byrd Green Bank Telescope (GBT), and the Very Long Baseline Array (VLBA)*.

    NRAO ALMA
    NRAO ALMA

    NRAO GBT
    NRAO GBT

    NRAO VLA
    NRAO VLA

    The NRAO is building two new major research facilities in partnership with the international community that will soon open new scientific frontiers: the Atacama Large Millimeter/submillimeter Array (ALMA), and the Expanded Very Large Array (EVLA). Access to ALMA observing time by the North American astronomical community will be through the North American ALMA Science Center (NAASC).
    *The Very Long Baseline Array (VLBA) comprises ten radio telescopes spanning 5,351 miles. It’s the world’s largest, sharpest, dedicated telescope array. With an eye this sharp, you could be in Los Angeles and clearly read a street sign in New York City!

    Astronomers use the continent-sized VLBA to zoom in on objects that shine brightly in radio waves, long-wavelength light that’s well below infrared on the spectrum. They observe blazars, quasars, black holes, and stars in every stage of the stellar life cycle. They plot pulsars, exoplanets, and masers, and track asteroids and planets.


    ScienceSprings is powered by MAINGEAR computers

     
  • richardmitnick 4:20 pm on September 9, 2013 Permalink | Reply
    Tags: , , , , National Radio Astronomy Observatory (NRAO),   

    From NRAO: “Newly Found Pulsar Helps Astronomers Explore Milky Way’s Mysterious Core” 

    NRAO Icon
    National Radio Astronomy Observatory

    NRAO Banner

    14 August 2013

    Dave Finley, Public Information Officer
    Socorro, NM
    (575) 835-7302
    dfinley@nrao.edu

    Astronomers have made an important measurement of the magnetic field emanating from a swirling disk of material surrounding the black hole at the center of our Milky Way Galaxy. The measurement, made by observing a recently-discovered pulsar, is providing them with a powerful new tool for studying the mysterious region at the core of our home galaxy.

    faraday
    Artist’s conception of PSR J745-2900 and Galactic Center.

    Like most galaxies, the Milky Way harbors a supermassive black hole at its center, some 26,000 light-years from Earth. The Milky Way’s central black hole is some four million times more massive than the Sun. Black holes, concentrations of mass so dense that not even light can escape them, can pull in material from their surroundings. That material usually forms a swirling disk around the black hole, with material falling from the outer portion of the disk inward until it is sucked into the black hole itself.

    Such disks concentrate not only the matter pulled into them but also the magnetic fields associated with that matter, forming a giant, twisting magnetic field that is thought to propel some of the matter back outward along its poles in superfast “jets.”

    The region near the black hole is obscured from visible-light observations by gas and dust, and is an exotic, extreme environment still little-understood by astronomers. The magnetic field in the central portion of the region is an important component that affects other phenomena.

    The first link to measuring the magnetic field near the black hole came last April when NASA’s Swift satellite detected a flare of X-rays from near the Milky Way’s center. Observers soon determined that the X-rays were coming in regular pulses. Follow-on observations with radio telescopes, including ones in Germany, France, and the National Science Foundation’s Karl G. Jansky Very Large Array (VLA), showed radio pulses identically spaced. The astronomers concluded the object, called PSR J1745-2900, is a magnetar, a highly-magnetized pulsar, or spinning neutron star.

    “The lucky alignment of this gas with a pulsar so close to the black hole has given us a valuable tool for understanding this difficult-to-observe environment,” said Paul Demorest, of the National Radio Astronomy Observatory.

    See the full article here.

    The NRAO operates a complementary, state-of-the-art suite of radio telescope facilities for use by the scientific community, regardless of institutional or national affiliation: the Very Large Array (VLA), the Robert C. Byrd Green Bank Telescope (GBT), and the Very Long Baseline Array (VLBA)*.

    NRAO ALMA
    NRAO ALMA

    NRAO GBT
    NRAO GBT

    NRAO VLA
    NRAO VLA

    The NRAO is building two new major research facilities in partnership with the international community that will soon open new scientific frontiers: the Atacama Large Millimeter/submillimeter Array (ALMA), and the Expanded Very Large Array (EVLA). Access to ALMA observing time by the North American astronomical community will be through the North American ALMA Science Center (NAASC).
    *The Very Long Baseline Array (VLBA) comprises ten radio telescopes spanning 5,351 miles. It’s the world’s largest, sharpest, dedicated telescope array. With an eye this sharp, you could be in Los Angeles and clearly read a street sign in New York City!

    Astronomers use the continent-sized VLBA to zoom in on objects that shine brightly in radio waves, long-wavelength light that’s well below infrared on the spectrum. They observe blazars, quasars, black holes, and stars in every stage of the stellar life cycle. They plot pulsars, exoplanets, and masers, and track asteroids and planets.

     
  • richardmitnick 6:46 pm on August 15, 2013 Permalink | Reply
    Tags: , , , , National Radio Astronomy Observatory (NRAO),   

    From NRAO: “Venerable NRAO Telescope Reborn as Earth-based Antenna for Orbiting RadioAstron Satellite” 

    NRAO Icon

    National Radio Astronomy Observatory

    NRAO Banner

    August 15, 2013
    Charles Blue, Public Information Officer
    Charlottesville, Virginia
    (434) 296-0314
    cblue@nrao.edu

    “The trailblazing 43 Meter (140 Foot) Telescope at the National Radio Astronomy Observatory (NRAO) in Green Bank, W.Va., has been given new life as one of only two Earth stations for the Russian-made RadioAstron satellite, the cornerstone of astronomy’s highest-resolution telescope.

    43
    Initial testing of the 43 Meter Telescope. The service tower is to the left and the 100m diameter GBT is in the middle background.

    ra
    RadioAstron Antenna

    RadioAstron is the farthest element of an Earth-to-space spanning radio telescope system. Launched in July 2011, RadioAstron — when linked to large, ground-based radio telescopes like NRAO’s massive Robert C. Byrd Green Bank Telescope (GBT) — creates a virtual radio telescope that extends up to 220,000 miles (350,000 kilometers) across, which is about the same distance as the Earth to the Moon.

    GBT
    Robert C. Byrd Green Bank Telescope (GBT)

    From late July 2013 through early August, engineers and astronomers from the United States and Russia successfully installed sophisticated receiving and signal processing instruments on NRAO’s 43 Meter Telescope, which was completed in 1965 and retired from routine astronomical observations in 2001. The telescope has now been transformed into one of only two antennas (the other near Moscow) that can receive and process the scientific data from RadioAstron. The addition of the antenna at Green Bank effectively doubles the spacecraft’s scientific capabilities.

    ‘NRAO has built the most capable radio telescopes in the world. After nearly half a century of service, the 43 Meter Telescope is once again proving its innovative design and precision construction have much to offer the astronomical community,’ said Karen O’Neil, the NRAO site director at Green Bank and project lead for the Green Bank portion of RadioAstron.

    ‘The international scientific community is excited about RadioAstron because of the unique science that it will enable,’ said Ken Kellermann, a scientist at the NRAO in Charlottesville, Va. ‘By combining its data with leading ground-based telescopes, we will have an incredibly powerful research tool, which will provide extraordinary angular resolution enabling the study of quasars, cosmic masers, and the interstellar medium in unprecedented detail.'”

    See the full article here.

    The NRAO operates a complementary, state-of-the-art suite of radio telescope facilities for use by the scientific community, regardless of institutional or national affiliation: the Very Large Array (VLA), the Robert C. Byrd Green Bank Telescope (GBT), and the Very Long Baseline Array (VLBA)*.

    NRAO ALMA
    NRAO ALMA

    NRAO GBT
    NRAO GBT

    NRAO VLA
    NRAO VLA

    The NRAO is building two new major research facilities in partnership with the international community that will soon open new scientific frontiers: the Atacama Large Millimeter/submillimeter Array (ALMA), and the Expanded Very Large Array (EVLA). Access to ALMA observing time by the North American astronomical community will be through the North American ALMA Science Center (NAASC).
    *The Very Long Baseline Array (VLBA) comprises ten radio telescopes spanning 5,351 miles. It’s the world’s largest, sharpest, dedicated telescope array. With an eye this sharp, you could be in Los Angeles and clearly read a street sign in New York City!

    Astronomers use the continent-sized VLBA to zoom in on objects that shine brightly in radio waves, long-wavelength light that’s well below infrared on the spectrum. They observe blazars, quasars, black holes, and stars in every stage of the stellar life cycle. They plot pulsars, exoplanets, and masers, and track asteroids and planets.

     
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