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  • richardmitnick 7:41 am on May 27, 2017 Permalink | Reply
    Tags: , , , , , , Radio Astronomy   

    From CSIRO: “ASKAP telescope speeds up the hunt for new Fast Radio Bursts” 

    CSIRO bloc

    Commonwealth Scientific and Industrial Research Organisation

    23rd May 2017
    Keith Bannister
    Jean-Pierre Macquart

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    ASKAP at night. Alex Cherney/terrastro.com, Author provided

    They’re mysterious bursts of radio waves from space that are over in a fraction of a second. Fast Radio Bursts (FRBs) are thought to occur many thousands of times a day, but since their first detection by the Parkes radio telescope a decade ago only 30 have been observed.

    CSIRO/Parkes Observatory, located 20 kilometres north of the town of Parkes, New South Wales, Australia

    But once the Australian Square Kilometre Array Pathfinder (ASKAP) joined the hunt we had our first new FRB after just three and half days of observing.

    This was soon followed by a further two FRBs. And the telescope is not even fully operational yet.

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    The first FRB that ASKAP found. Bottom panel shows a grey scale image of what the FRB looks like. It’s less than 1 millisecond long and we detect it over a range of frequencies from 1,100 MHz to 1,400 MHz. The top panel shows what the FRB looks like when you add up all the frequency channels. Ryan Shannon (CSIRO/Curtin University), Author provided.

    The fact that ASKAP detects FRBs so readily means it is now poised to tackle the big questions.

    One of these is what causes an FRB in the first place. They are variously attributed by hard-nosed and self-respecting physicists to everything from microwave ovens, to the accidental transmissions of extraterrestrials making their first baby steps in interstellar exploration.

    The astounding properties of these FRBs have so enthralled astronomers that, in the decade since their discovery, there are more theories than observed bursts.

    A distant flash

    FRBs are remarkable because they are outrageously bright in the radio spectrum yet appear extremely distant. As far as astronomers can tell, they come from a long way away – halfway across the observable universe or more. Because of that, whatever makes FRBs must be pretty special, unlike anything astronomers have ever seen.

    What has astronomers really excited is the fossil record imprinted on each burst by the matter it encounters during its multibillion-year crossing of the universe.

    Matter in space exerts a tiny amount drag on the radio waves as they hurtle across the universe, like the air drags on a fast-moving plane. But here’s the handy bit: the longer the radio waves, the more the drag.

    By the time the radio waves arrive at our telescopes, the shorter waves arrive just before the longer ones. By measuring the time delay between the short waves and the longer ones, astronomers can work out how much matter a given burst has travelled through on its journey from whatever made it, to our telescope.

    If we can find enough bursts, we can work out how much ordinary matter – the stuff you and I and all visible matter is made of – exists in the universe, and tally up its mass.

    The best guess so far is that we are missing roughly half of all the normal matter, with the rest lying in the vast voids between the galaxies — the very regions so readily probed by FRBs.

    Are FRBs the weigh stations of the cosmos?

    Difficult to find and harder to pinpoint

    There are a few reasons why we still have so many questions about FRBs. First, they are tricky to find. It takes the Parkes telescope around two weeks of constant watching to find a burst.

    Worse, even when you’ve found one, many radio telescopes like Parkes can only pinpoint its location in the sky to a region about the size of the full Moon. If you want to work out which galaxy an FRB came from, you have hundreds to choose from within that area.

    The ideal FRB detector needs both a large field of view and the ability to pinpoint events to a region one thousandth the area of the Moon. Until recently, no such radio telescope existed.

    A jewel in the desert

    Now it does in ASKAP, a radio telescope being built by the CSIRO in Murchison Shire, 370km northeast of Geraldton in Western Australia. It’s actually a network of 36 antennas, each 12 metres in diameter.

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    ASKAP antennas during fly’s-eye observing. All the antennas point in different directions. Kim Steele (Curtin University), Author provided.

    ASKAP is a very special machine, because each antenna is equipped with an innovative CSIRO-designed receiver called a phased-array feed. While most radio telescopes see just one patch of sky at time, ASKAP’s phased-array feeds see 36 different patches of sky simultaneously. This is great for finding FRBs because the more sky you can see, the better chance you have of finding them.

    To find lots of FRBs we need to cast an even wider net. Normally, ASKAP dishes all point in the same direction. This is great if you’re making images or want to find faint FRBs.

    Thanks to recent evidence from Parkes, we realised there might be some super-bright FRBs too.

    So we took a hint from nature. In the same way that the segments of a fly’s eye allow it to see all around it, we pointed all our antennas in lots of different directions. This fly’s-eye observing mode enabled us to see a total patch of sky about the size of 1,000 full Moons.

    That’s how we discovered this new FRB within days of starting, and using just eight of ASKAP’s total of 36 antennas.

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    Radio image of the sky where ASKAP found its first FRB. The blue circles are the 36 patches of the sky that ASKAP antenna number 5 (named Gagurla in the local Wadjarri language) was watching at the time the FRB was detected. The red smudge marks where the FRB came from. The black dots are galaxies, far, far, away. The full Moon is shown to scale, in the bottom corner. Ian Heywood (CSIRO), Author provided

    When fully operational

    So far, in fly’s-eye mode we have made no attempt to combine the signals from all the antennas. ASKAP’s real party piece will be to point all the telescopes in the same direction and combine the signals from all the antennas.

    This will give us a precise position for every single burst, enabling us to identify the host galaxy of each FRB and measure its exact distance.

    Armed with this information, we will be able to activate our network of cosmic weigh stations. At this point we will be able to investigate a fundamental question that has been plaguing astronomers for more than 20 years: where is the missing matter in the universe?

    See the full article here .

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    CSIRO campus

    CSIRO, the Commonwealth Scientific and Industrial Research Organisation, is Australia’s national science agency and one of the largest and most diverse research agencies in the world.

     
  • richardmitnick 6:51 am on May 27, 2017 Permalink | Reply
    Tags: , , , , , , FRB 121102, , NRAO/VLA, Radio Astronomy   

    From McGill: “Homing in on source of mysterious cosmic radio bursts” 

    McGill University

    McGill University

    4 Jan 2017
    No writer credit found

    1

    Astronomers have pinpointed for the first time the home galaxy of a Fast Radio Burst, moving scientists a step closer to detecting what causes these powerful but fleeting pulses of radio waves. FRBs, which last just a few thousandths of a second, have puzzled astrophysicists since their discovery a decade ago.

    “Now we know that at least one of these FRBs originated within a dwarf galaxy located some three billion light-years beyond our Milky Way galaxy,” said McGill University postdoctoral researcher Shriharsh Tendulkar. He and other astronomers presented the findings today at the meeting of the American Astronomical Society in Grapevine, Texas. Results of the research are also published in the journal Nature and in companion papers in The Astrophysical Journal Letters [Tendulkar, S. P., et al. 2017, ApJL, 834, L7. http://iopscience.iop.org/article/10.3847/2041-8213/834/2/L7%5D and [Marcote, B., et al. 2017, ApJL, 834, L8. http://iopscience.iop.org/article/10.3847/2041-8213/834/2/L8%5D.

    Until now, astronomers hadn’t even been able to determine with certainty whether FRBs come from within our galaxy or beyond. While the exact cause of the high-energy bursts remains unclear, the fact that this particular FRB comes from a distant dwarf galaxy represents “a huge advance in our understanding of these events,” said Shami Chatterjee of Cornell University, another member of the international research team that produced the new results.

    A recurring FRB

    There are now 18 known FRBs. All were detected using single-dish radio telescopes that are unable to narrow down the object’s location with enough precision to allow other observatories to identify its host environment. Unlike all the others, however, one FRB, discovered in November of 2012 at the Arecibo Observatory in Puerto Rico, has recurred numerous times – a pattern first detected in late 2015 by McGill PhD student Paul Scholz.

    NAIC/Arecibo Observatory, Puerto Rico, USA

    The repeating bursts from this object, named FRB 121102 after the date of the initial burst, allowed astronomers to watch for it this year using the National Science Foundation’s (NSF) Karl G. Jansky Very Large Array (VLA), a multi-antenna radio telescope system with the resolving power, or ability to see fine detail, needed to precisely determine the object’s location in the sky.

    NRAO/VLA, on the Plains of San Agustin fifty miles west of Socorro, NM, USA

    In 83 hours of observing time over six months in 2016, the VLA detected nine bursts from FRB 121102.

    Using the precise VLA position, Tendulkar and other researchers used the Gemini North telescope in Hawaii to make a visible-light image that identified a faint dwarf galaxy at the location of the bursts. Spectroscopic data from Gemini also enabled the researchers to determine that the dwarf galaxy is more than 3 billion light-years from Earth.

    A humble, unassuming host galaxy

    “The host galaxy for this FRB appears to be a very humble and unassuming dwarf galaxy, which is less than 1% of the mass or our Milky Way galaxy,” Tendulkar says. “That’s surprising. One would generally expect most FRBs to come from large galaxies which have the largest numbers of stars and neutron stars — remnants of massive stars. This dwarf galaxy has fewer stars, but is forming stars at a high rate, which may suggest that FRBs are linked to young neutron stars. There are also two other classes of extreme events — long duration gamma-ray bursts and superluminous supernovae — that frequently occur in dwarf galaxies, as well. This discovery may hint at links between FRBs and those two kinds of events.”

    In addition to detecting the bright bursts from FRB 121102, the VLA observations also revealed an ongoing, persistent source of weaker radio emission in the same region.

    Next, a team of observers used the multiple radio telescopes of the European VLBI Network (EVN), along with the 1,000-foot-diameter William E. Gordon Telescope of the Arecibo Observatory, and the NSF’s Very Long Baseline Array (VLBA) to determine the object’s position with even greater accuracy.

    European VLBI

    “These ultra-high precision observations showed that the bursts and the persistent source must be within 100 light-years of each other,” said Jason Hessels, of the Netherlands Institute for Radio Astronomy and the University of Amsterdam.

    “We think that the bursts and the continuous source are likely to be either the same object or that they are somehow physically associated with each other,” said Benito Marcote, of the Joint Institute for VLBI ERIC, Dwingeloo, Netherlands.

    CHIME could help solve puzzle

    The top candidates, the astronomers suggested, are a young neutron star, possibly a highly-magnetic magnetar, surrounded by either material ejected by a supernova explosion or material ejected by a resulting pulsar, or an active supermassive black hole in the galaxy, with radio emission coming from jets of material emitted from the region surrounding the black hole.

    Now, thanks to new images from the Hubble Space Telescope and the 8.2-metre Subaru Telescope in Hawaii, the McGill researchers and a separate team from Tohoku University in Japan have honed in on the source of FRB 121102 even further – to a giant stellar nursery near the centre of the distant dwarf galaxy.

    NASA/ESA Hubble Telescope


    NAOJ/Subaru Telescope at Mauna Kea Hawaii, USA

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    5.25.17 New Scientist.Making signals from afar.John R. Foster/SCIENCE PHOTO LIBRARY

    “The Hubble and Subaru images show that the star-forming complex lies on the small galaxy’s outskirts,” Ken Croswell reports for New Scientist.

    “There is still a lot of work to do to unravel the mystery surrounding FRBs,” says McGill physics professor Victoria Kaspi, a senior member of the international team that conducted the new studies. “But identifying the host galaxy for this repeating FRB marks a big step toward solving the puzzle.”

    The Canadian Hydrogen Intensity Mapping Experiment (CHIME), an interferometric radio telescope in British Columbia, could help answer remaining questions, Kaspi notes. CHIME will survey half the sky each day, potentially enabling it to detect dozens of FRBs per day, she says. “Once we understand the origin of this phenomenon, it could provide us with a new and valuable probe of the Universe.”

    CHIME Canadian Hydrogen Intensity Mapping Experiment A partnership between the University of British Columbia McGill University

    The research was supported in part by the National Research Council of Canada, the Natural Sciences and Engineering Research Council of Canada, the Canadian Institute for Advanced Research, the Lorne Trottier Chair in Astrophysics and Cosmology, the European Research Council, and the National Science Foundation (U.S.).

    See the full article here .

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    All about McGill

    With some 300 buildings, more than 38,500 students and 250,000 living alumni, and a reputation for excellence that reaches around the globe, McGill has carved out a spot among the world’s greatest universities.
    Founded in Montreal, Quebec, in 1821, McGill is a leading Canadian post-secondary institution. It has two campuses, 11 faculties, 11 professional schools, 300 programs of study and some 39,000 students, including more than 9,300 graduate students. McGill attracts students from over 150 countries around the world, its 8,200 international students making up 21 per cent of the student body.

     
  • richardmitnick 3:25 pm on May 23, 2017 Permalink | Reply
    Tags: , , , , , Here’s How We Can Detect Plants on Extrasolar Planets, Polarized Light from Atmospheres of Nearby Extra-Terrestrial Planets (PLANETS) telescope, Radio Astronomy,   

    From UniverseToday: “Here’s How We Can Detect Plants on Extrasolar Planets” 

    universe-today

    Universe Today

    23 May , 2017
    Matt Williams

    The past year has been an exciting time for those engaged in the hunt for extra-solar planets and potentially habitable worlds. In August of 2016, researchers from the European Southern Observatory (ESO) confirmed the existence of the closest exoplanet to Earth (Proxima b) yet discovered. This was followed a few months later (February of 2017) with the announcement of a seven-planet system around TRAPPIST-1.

    Centauris Alpha Beta Proxima 27, February 2012. Skatebiker

    The TRAPPIST-1 star, an ultracool dwarf, is orbited by seven Earth-size planets (NASA).

    … at this year’s Breakthrough Discuss conference…Dr. Svetlana Berdyugina…indicated during the course of the presentation, the same instruments and methods used to study and characterize distant stars could be used to confirm the presence of continents and vegetation on the surface of distant exoplanets. The key here – as as been demonstrated by decades of Earth observation – is to observe the reflected light (or “light curve”) coming from their surfaces.

    Measurements of a star’s light curve are used to to determine what type of class a star is and what processes are at work within it. Light curves are also routinely used to discern the presence of planets around stars – aka. the Transit Method, where a planet transiting in front of a star causes a measurable dip in its brightness – as well as determining the size and orbital period of the planet.

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    Diagram illustrating how the absorption of light can be used to determine the presence of vegetation on an extra-solar planet. Credit: S. Berdyugina.

    …illustrated by the diagram above, green vegetation absorbs almost all the red, green and blue (RGB) parts of the spectrum, but reflects infrared light. This sort of process has been used for decades by Earth observation satellites to track meteorological phenomena, measure the extent of forests and vegetation, track the expansion of population centers, and monitor the growth of deserts.

    In addition, the presence of biopigments caused by chlorophyll means that the reflected RGB light would be highly-polarized while UR light would be weakly polarized. This will allow astronomers to tell the difference between vegetation and something that is simply green in color. To gather this information, she stated, will require the work of off-axis telescopes that are both large and high-contrast.

    These are expected to include the Colossus Telescope, a project for a massive telescope that is being spearheaded by the Planets Foundation – and for which Dr. Berdyugina is the project lead.

    Colossus telescope, as yet there are no notes about location

    Once completed, Colossus will be the largest optical and infrared telescope in the world, not to mention the largest telescope optimized for detecting extrasolar life and extraterrestrial civilizations.

    And then there’s the Polarized Light from Atmospheres of Nearby Extra-Terrestrial Planets (PLANETS) telescope, which is currently being constructed in Haleakala, Hawaii (expected to be completed by January 2018).

    3

    Here too, this telescope is a technology demonstrator for what will eventually go into making Colossus a reality.

    See the full article here .
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  • richardmitnick 1:20 pm on May 18, 2017 Permalink | Reply
    Tags: APEX Low-redshift Legacy Survey of MOlecular Gas, , , , , Radio Astronomy,   

    From SKA: “International team completes large survey of gas in nearby galaxies” 

    SKA Square Kilometer Array

    SKA

    An international team of investigators led by Dr. Claudia Cicone (INAF – Astronomical Observatory of Brera), Dr. Matt Bothwell (University of Cambridge) and with the SKA Organisation Project Scientist Dr. Jeff Wagg as principal investigator have found the spectra of the carbon monoxide emission line in a sample of small but nearby galaxies and found that the most massive galaxies form stars and are rich in metals.

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    The 12m APEX ESO telescope, located on the plateau of Chajnantor in Chile, at 5000m altitude.

    The team, comprising investigators from Italy, the UK, Germany, Chile and China have completed a large survey of molecular gas in nearby galaxies using the 12m APEX telescope in Chile. The APEX Low-redshift Legacy Survey of MOlecular Gas (ALLSMOG, PI: Dr. Jeff Wagg) has observed the Carbon Monoxide (CO) molecule in a sample of 97 galaxies in the local Universe. The ALLSMOG data provide important information on the cold molecular gas content of these galaxies which have been well characterised in terms of their star-formation rates, gas-phase metallicities and atomic HI gas masses.

    ALLSMOG is an ESO observing program conceived by Dr. Jeff Wagg to study the molecular gas through the carbon monoxide emission line with the telescope Atacama Pathfinder Experiment (Apex), a collaboration between the Max Planck Institute for Radio Astronomy (MPIfR), the Onsala Space Observatory (Oso) and ESO, which is located on the plain of Chajnantor at 5000 meters above sea level, in the Chilean Andes.

    The article The final release date of ALLSMOG: a survey of CO in typical local low-M star-forming galaxies published today in the journal Astronomy & Astrophysics includes observations of 97 galaxies, 88 of whom studied with Apex (for more than 300 hours of observation from summer 2013 to winter 2015/2016) and 9 with the telescope of the Institute of millimetric radio astronomy (Iram) to Pico Veleta, Spain (between 2014 and 2015).

    IRAM 30m Radio telescope, on Pico Veleta in the Spanish Sierra Nevada

    The survey is the first major campaign ALLSMOG systematic observation of carbon monoxide extragalactic made with Apex telescope.

    “The ALLSMOG survey is the first large systematic extragalactic survey of CO ever conducted with the APEX telescope”, says Claudia Cicone, a Marie Skłodowska-Curie fellow at INAF- Osservatorio Astronomico di Brera. “Our research has an enormous legacy value because the entire scientific community can exploit our data. We really hope our efforts will stimulate new ideas and results.”

    “For all the galaxies in our sample we have additional information on their physical properties from optical observations and on their atomic gas content (HI) from radio observations of the HI21cm line published in previous studies and by other teams. We have created a real identikit of these galaxies which allows us to study the relations between the molecular gas and their other physical properties.”

    “In the near future, multi-wavelength galaxy studies like this will be greatly enhanced by data from the SKA telescope and its precursors such as ASKAP and MeerKAT”, says Dr. Jeff Wagg.

    SKA/ASKAP radio telescope at the Murchison Radio-astronomy Observatory (MRO) in Mid West region of Western Australia

    SKA Meerkat telescope, 90 km outside the small Northern Cape town of Carnarvon, SA

    “While the SKA precursors are expected to detect more than half a million galaxies in HI line emission, these sample sizes have the potential to increase by nearly an order of magnitude when the SKA1-mid telescope comes online.”

    SKA1-mid is the dish array telescope to be built in South Africa that will be operating in the 350Mhz -14Ghz frequency range, complementary to the low-frequency telescope (so-called SKA1-low) to be built in Australia. Although SKA1-mid and the SKA precursors do not have the frequency coverage needed to measure the molecular gas in nearby galaxies, they will be able to detect the atomic gas through the 21cm atomic HI line transition.

    “Quantifying the total gas content (atomic and molecular) of significant samples of galaxies out to large distances remains one of the crucial elements needed for a full understanding of galaxy formation”, concludes Dr. Jeff Wagg.

    See the full article here .

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    SKA CSIRO  Pathfinder Telescope
    SKA ASKAP Pathefinder Telescope

    SKA Meerkat telescope
    SKA Meerkat Telescope

    SKA Murchison Widefield Array
    SKA Murchison Wide Field Array

    About SKA

    The Square Kilometre Array will be the world’s largest and most sensitive radio telescope. The total collecting area will be approximately one square kilometre giving 50 times the sensitivity, and 10 000 times the survey speed, of the best current-day telescopes. The SKA will be built in Southern Africa and in Australia. Thousands of receptors will extend to distances of 3 000 km from the central regions. The SKA will address fundamental unanswered questions about our Universe including how the first stars and galaxies formed after the Big Bang, how dark energy is accelerating the expansion of the Universe, the role of magnetism in the cosmos, the nature of gravity, and the search for life beyond Earth. Construction of phase one of the SKA is scheduled to start in 2016. The SKA Organisation, with its headquarters at Jodrell Bank Observatory, near Manchester, UK, was established in December 2011 as a not-for-profit company in order to formalise relationships between the international partners and centralise the leadership of the project.

    The Square Kilometre Array (SKA) project is an international effort to build the world’s largest radio telescope, led by SKA Organisation. The SKA will conduct transformational science to improve our understanding of the Universe and the laws of fundamental physics, monitoring the sky in unprecedented detail and mapping it hundreds of times faster than any current facility.

    Already supported by 10 member countries – Australia, Canada, China, India, Italy, New Zealand, South Africa, Sweden, The Netherlands and the United Kingdom – SKA Organisation has brought together some of the world’s finest scientists, engineers and policy makers and more than 100 companies and research institutions across 20 countries in the design and development of the telescope. Construction of the SKA is set to start in 2018, with early science observations in 2020.

     
  • richardmitnick 11:22 am on May 18, 2017 Permalink | Reply
    Tags: , , , , , Fomalhaut star system, , Radio Astronomy   

    From ALMA: “ALMA Eyes Icy Ring Around Young Planetary System” 

    ESO/NRAO/NAOJ ALMA Array
    ESO/NRAO/NAOJ ALMA Array in Chile in the Atacama at Chajnantor plateau, at 5,000 metres
    ALMA

    18 May 2017
    Nicolás Lira T.
    Press Coordinator
    Joint ALMA Observatory
    Santiago, Chile
    Tel: +56 2 24 67 65 19
    Cell: +56 9 94 45 77 26
    Email: nicolas.lira@alma.cl

    Charles E. Blue
    Public Information Officer
    National Radio Astronomy Observatory
    Charlottesville, Virginia, USA
    Tel: +1 434 296 0314
    Cell: +1 202 236 6324
    E-mail: cblue@nrao.edu

    Masaaki Hiramatsu

    Education and Public Outreach Officer, NAOJ Chile
    Observatory
Tokyo, Japan

    Tel: +81 422 34 3630

    E-mail: hiramatsu.masaaki@nao.ac.jp

    Richard Hook
    Public Information Officer, ESO

    Garching bei München, Germany

    Tel: +49 89 3200 6655

    Cell: +49 151 1537 3591
    Email: rhook@eso.org

    1
    Composite image of the Fomalhaut star system. The ALMA data, shown in orange, reveal the distant and eccentric debris disk in never-before-seen detail. The central dot is the unresolved emission from the star, which is about twice the mass of the Sun. Optical data from the Hubble Space Telescope is in blue; the dark region is a coronagraphic mask, which filtered out the otherwise overwhelming light of the central star. Credit: ALMA (ESO/NAOJ/NRAO), M. MacGregor; NASA/ESA Hubble, P. Kalas; B. Saxton (NRAO/AUI/NSF)

    NASA/ESA Hubble Telescope

    An international team of astronomers using the Atacama Large Millimeter/submillimeter Array (ALMA) has made the first complete millimeter-wavelength image of the ring of dusty debris surrounding the young star Fomalhaut. This remarkably well-defined band of rubble and gas is likely the result of exocomets smashing together near the outer edges of a planetary system 25 light-years from Earth. Observations Suggest Chemical Kinship to Comets in Our Own Solar System.

    Earlier ALMA observations of Fomalhaut — taken in 2012 when the telescope was still under construction – revealed only about one half of the debris disk.

    2

    Though this first image was merely a test of ALMA’s initial capabilities, it nonetheless provided tantalizing hints about the nature and possible origin of the disk.

    The new ALMA observations offer a stunningly complete view of this glowing band of debris and suggest that there are chemical similarities between its icy contents and comets in our own solar system.

    “ALMA has given us this staggeringly clear image of a fully formed debris disk,” said Meredith MacGregor, an astronomer at the Harvard-Smithsonian Center for Astrophysics in Cambridge, Massachusetts, USA, and lead author on one of two papers accepted for publication in the Astrophysical Journal describing these observations. “We can finally see the well-defined shape of the disk, which may tell us a great deal about the underlying planetary system responsible for its highly distinctive appearance.”

    Fomalhaut is a relatively nearby star system and one of only about 20 in which planets have been imaged directly. The entire system is approximately 440 million years old, or about one-tenth the age of our solar system.

    As revealed in the new ALMA image, a brilliant band of icy dust about 2 billion kilometers wide has formed approximately 20 billion kilometers from the star.

    Debris disks are common features around young stars and represent a very dynamic and chaotic period in the history of a solar system. Astronomers believe they are formed by the ongoing collisions of comets and other planetesimals in the outer reaches of a recently formed planetary system. The leftover debris from these collisions absorbs light from its central star and reradiates that energy as a faint millimeter-wavelength glow that can be studied with ALMA.

    Using the new ALMA data and detailed computer modeling, the researchers could calculate the precise location, width, and geometry of the disk. These parameters confirm that such a narrow ring is likely produced through the gravitational influence of planets in the system, noted MacGregor.

    The new ALMA observations are also the first to definitively show “apocenter glow,” a phenomenon predicted in a 2016 paper by lead author Margaret Pan, a scientist at the Massachusetts Institute of Technology in Cambridge and co-author on the new ALMA papers. Like all objects with elongated orbits, the dusty material in the Fomalhaut disk travels more slowly when it is farthest from the star. As the dust slows down, it piles up, forming denser concentrations in the more distant portions of the disk. These dense regions can be seen by ALMA as brighter millimeter-wavelength emission.

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    ALMA image of the debris disk in the Fomalhaut star system. The ring is approximately 20 billion kilometers from the central star and it is about 2 billion kilometers wide. The central dot is the unresolved emission from the star, which is about twice the mass of the Sun. Credit: ALMA (ESO/NAOJ/NRAO); M. MacGregor

    Using the same ALMA dataset, but focusing on distinct millimeter-wavelength signals naturally emitted by molecules in space, the researchers also detected vast stores of carbon monoxide gas in precisely the same location as the debris disk.

    “These data allowed us to determine that the relative abundance of carbon monoxide plus carbon dioxide around Fomalhaut is about the same as found in comets in our own solar system,” said Luca Matrà with the University of Cambridge, UK, and lead author on the team’s second paper. “This chemical kinship may indicate a similarity in comet formation conditions between the outer reaches of this planetary system and our own.” Matrà and his colleagues believe this gas is either released from continuous comet collisions or the result of a single, large impact between supercomets hundreds of times more massive than Hale-Bopp.

    The presence of this well-defined debris disk around Fomalhaut, along with its curiously familiar chemistry, may indicate that this system is undergoing its own version of the Late Heavy Bombardment, a period approximately 4 billion years ago when the Earth and other planets were routinely struck by swarms of asteroids and comets left over from the formation of the Solar System.

    “Twenty years ago, the best millimeter-wavelength telescopes gave the first fuzzy maps of sand grains orbiting Fomalhaut. Now with ALMA’s full capabilities the entire ring of material has been imaged,” concluded Paul Kalas, an astronomer at the University of California at Berkeley and principal investigator on these observations. “One day we hope to detect the planets that influence the orbits of these grains.”

    Additional information

    This research is presented in a paper titled A complete ALMA map of the Fomalhaut debris disk, M. MacGregor, et al., appearing in the Astrophysical Journal, and Detection of exocometary CO within the 440MYR-old Fomalhaut belt: A similar CO+CO2 ice abundance in exocomets and solar system comets, L. Matrà et al., appearing in the Astrophysical Journal.

    This work benefited from: NASA’s Nexus for Exoplanet System Science (NExSS) research coordination network sponsored by NASA’s Science Mission Directorate, NASA grants NNX15AC89G, NNX15AD95G, NSF grant AST-1518332, NSF Graduate Research Fellowship DGE1144152, and from NRAO Student Observing Support. This work has also been possible thanks to an STFC postgraduate studentship and the European Union through ERC grant number 279973.

    See the full article here .

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    The Atacama Large Millimeter/submillimeter Array (ALMA), an international astronomy facility, is a partnership of Europe, North America and East Asia in cooperation with the Republic of Chile. ALMA is funded in Europe by the European Organization for Astronomical Research in the Southern Hemisphere (ESO), in North America by the U.S. National Science Foundation (NSF) in cooperation with the National Research Council of Canada (NRC) and the National Science Council of Taiwan (NSC) and in East Asia by the National Institutes of Natural Sciences (NINS) of Japan in cooperation with the Academia Sinica (AS) in Taiwan.

    ALMA construction and operations are led on behalf of Europe by ESO, on behalf of North America by the National Radio Astronomy Observatory (NRAO), which is managed by Associated Universities, Inc. (AUI) 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.

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  • richardmitnick 11:26 am on May 17, 2017 Permalink | Reply
    Tags: , , , , , , , Maura McLaughlin, , , Radio Astronomy,   

    From Physics: Women in STEM – “Q and A: Catching a Gravitational Wave with a Pulsar’s Beam” Maura McLaughlin 

    Physics LogoAbout Physics

    Physics Logo 2

    Physics

    May 12, 2017
    Katherine Wright

    Maura McLaughlin explains how the electromagnetic signals from fast-spinning neutron stars could be used to detect gravitational waves.

    1
    Maura McLaughlin. Greg Ellis/West Virginia University

    Pulsars captivate Maura McLaughlin, a professor at West Virginia University. These highly magnetized neutron stars flash beams of electromagnetic radiation as they spin. And with masses equivalent to that of the Sun, but diameters seventy thousand times smaller, they are—besides black holes—the densest objects in the Universe. Astrophysicists still have many questions about pulsars, ranging from how they emit electromagnetic radiation to why they are so incredibly dense. But it’s exploiting the highly stable, periodic electromagnetic signals of pulsars to study gravitational waves that currently has McLaughlin hooked. In an interview with Physics, she explained where her fascination with pulsars came from, what gravitational-wave sources she hopes to detect, and why she recently visited Washington, D.C., to talk with members of Congress.

    With the 2015 detection of gravitational waves, it’s obviously an exciting time to work in astrophysics. But what initially drew you to the field and to pulsars?

    The astrophysicist Alex Wolszczan. I met him in the early 90s while I was an undergrad at Penn State, and just after he had discovered the first extrasolar planets. These planets were orbiting a pulsar—lots of people don’t know that. I found this pulsar system fascinating and ended up working with Wolszczan one summer as a research assistant. I got to go to Puerto Rico to observe pulsars at the Arecibo Observatory, which is the biggest telescope in the world. The experience was really cool.
    How do researchers detect gravitational waves with pulsars?

    The collaboration that I’m part of—NANOGrav—is searching for changes in the travel time of the pulsar’s radio emission due to the passing of gravitational waves.

    2

    NANOGrave Gravitational waves JPL-Caltech David Champion

    When a gravitational wave passes between us and the pulsar, it stretches and squeezes spacetime, causing the pulse to arrive a bit earlier or later than it would in the absence of the wave. We time the arrival of pulsar signals for years to try to detect these small changes.
    What gravitational-wave-producing events do you expect to detect with pulsars? Could you see the same events as LIGO did?

    LIGO is sensitive to very short time-scale gravitational waves, on the order of milliseconds to seconds, while our experiment is sensitive to very long time-scale gravitational waves, on the order of years. We could never detect gravitational waves from two stellar-mass black holes merging—the time scale of the event is just too short. But we will be able to detect waves from black hole binaries in their inspiralling stage, when they’re still orbiting each other with periods of years. Also, our approach can only detect black holes that are much more massive that those LIGO observed. Our primary targets are supermassive black holes, even more massive than the one at the core of the Milky Way.


    Caltech/MIT Advanced aLigo Hanford, WA, USA installation


    Caltech/MIT Advanced aLigo detector installation Livingston, LA, USA

    Cornell SXS, the Simulating eXtreme Spacetimes (SXS) project


    Gravitational waves. Credit: MPI for Gravitational Physics/W.Benger-Zib

    ESA/eLISA the future of gravitational wave research

    LIGO is basically probing the evolution and end products of stars, whereas our experiment is probing the evolution of galaxies and the cosmos. We’ll be able to look way back in time at the processes by which galaxies formed through mergers.
    The first detection of gravitational waves was front-page news. What impact has it had on your research?

    I, and others in NANOGrav, got lots of condolences after LIGO’s detection, like “oh we’re sorry you weren’t first.” But it’s been good for us. It has really spurred us on to make a detection. And it has made us more optimistic—if it worked for LIGO it should work for us, as our methods are rooted in the same principles. None of us doubted gravitational waves existed, but as far as funding agencies and the public go, LIGO’s detection makes a big difference. Now people can’t say, “Who knows if these things exist?” or “Who knows if these methods work?” LIGO’s detection has shown they do exist and the methods do work.

    Apart from doubters, what other challenges do you face with your pulsar experiment?

    Right now, our most significant challenge is that our radio telescopes are in danger of being shut down. Both Arecibo and the Green Bank Telescope (GBT) in West Virginia are suffering significant funding cuts.

    NAIC/Arecibo Observatory, Puerto Rico, USA



    GBO radio telescope, Green Bank, West Virginia, USA

    Many of our NANOGrav discussions lately are about what we can do to retain access to these telescopes. Losing one of these telescopes would reduce our experiment’s sensitivity by roughly half and increase the time to detection by at least several years. If we lose both, our project is dead in the water. Arecibo and GBT are currently the two most sensitive radio telescopes in the world . I think its crazy that they are possibly being shut down.

    [Do not forget FAST-China]

    FAST radio telescope, now operating, located in the Dawodang depression in Pingtang county Guizhou Province, South China

    What are you doing to address the problem?

    I recently spent two days on Capitol Hill in Washington, D.C., talking to senators and House representatives trying to make the case to keep GBT open. Most of the politicians actually agreed it should stay open; it’s just a matter of funding. Science in general just doesn’t have enough funding.

    How do you frame the issues when talking to politicians about science?

    I try really hard to stress the opportunities for training students, the infrastructure, and the number of people who work at these telescopes. The technologies developed at the facilities are cutting edge and can be used for more than studying space. The science is incredibly interesting, but that in itself doesn’t always appeal to everybody.

    With the current administration, arguments of US prominence are also really valuable. China [has built ans is operating] a bigger telescope than Arecibo, and soon we won’t have the largest radio telescope in the world. Right now we are world leaders, but if the US wants to keeps its dominance then these telescopes have to remain open.

    With the challenges you face, what would you say to someone thinking of joining this field?

    Despite uncertainties with the telescopes, the future is bright. Now is a really good time to join the field: we’re going to make a detection any day now.

    See the full article here .

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    Physicists are drowning in a flood of research papers in their own fields and coping with an even larger deluge in other areas of physics. How can an active researcher stay informed about the most important developments in physics? Physics highlights a selection of papers from the Physical Review journals. In consultation with expert scientists, the editors choose these papers for their importance and/or intrinsic interest. To highlight these papers, Physics features three kinds of articles: Viewpoints are commentaries written by active researchers, who are asked to explain the results to physicists in other subfields. Focus stories are written by professional science writers in a journalistic style and are intended to be accessible to students and non-experts. Synopses are brief editor-written summaries. Physics provides a much-needed guide to the best in physics, and we welcome your comments (physics@aps.org).

     
  • richardmitnick 2:47 pm on May 14, 2017 Permalink | Reply
    Tags: , , , , European Very Long Baseline Interferometry (VLBI) Network, Ghana telescope heralds first pan-African array, Kuntunse Ghana telescope, Radio Astronomy,   

    From Nature: “Ghana telescope heralds first pan-African array” 

    Nature Mag
    Nature

    09 May 2017
    Sarah Wild

    By converting a defunct communications dish, astronomers are breaking ground on Earth and beyond.

    1
    An old communications dish in Ghana is taking on a new role as a radio telescope. SKA SA

    In a milestone for African astronomy, engineers have converted an old telecommunications dish in Ghana into the continent’s first functioning radio telescope outside South Africa.

    The telescope, in Kuntunse near Accra, is the first of an array of such instruments expected to be built across Africa over the next five years, and forms part of long-term plans to develop the skills of astronomers on the continent. It made its first observations this year and will be formally opened later in 2017.

    “It’s a moment of pride and joy that we have reached this far,” says project manager T. L. Venkatasubramani (known as VenKAT). He says that science operations should begin next year.

    Once up and running, the Ghana telescope could be incorporated into the European Very Long Baseline Interferometry (VLBI) Network — a cluster of far-apart radio telescopes that together act as one large instrument.

    European VLBI

    But astronomers also want to use it in a separate African VLBI Network (AVN).

    SKA South Africa

    For that, plans are under way to convert telecommunications dishes in Zambia, Madagascar and Kenya by mid-2019. The arrival of undersea cables around Africa’s coast in the past decade has rendered these dishes obsolete for their original purpose. New telescopes could also be built in four other African nations by mid-2022.

    The AVN will develop the capacity for astronomy in countries that have never had a radio telescope, says Huib Jan van Langevelde, director of the Joint Institute for VLBI in Europe, based in Dwingeloo, the Netherlands, who has been involved in training and testing for the African network. But it will also contribute useful science, he notes.

    The Ghana telescope has begun observing methanol masers — radio emissions that can arise from a number of celestial phenomena — and pulsars. The AVN will fill in geographic gaps in the global VLBI, improving imaging by increasing the range of distances and possible angles between the telescopes in the network. The more telescopes there are in a VLBI network, the more detail astronomers can see.

    “If you look at the current VLBI network, we definitely do need antennas filling up the centre of Africa,” says James Chibueze, a VLBI scientist and AVN operator who works with SKA South Africa in Cape Town, which is building part of the world’s largest radio telescope, the Square Kilometre Array.

    Tony Beasley, director of the US National Radio Astronomy Observatory in Charlottesville, Virginia, says the AVN is a “fantastic” initiative for the Southern Hemisphere, where the VLBI at present shares use of an array in Australia.

    “The AVN would be a full-time array, would do a lot more science and is going to increase by an order of magnitude the amount of VLBI time available, and the southern skies thing is unique. We have lots of arrays in the Northern Hemisphere,” he says.

    The AVN would also benefit from the technical advances made for the SKA and South Africa’s radio-astronomy ambitions, says Beasley.

    Tricky conversion

    The AVN was the brain child of Michael Gaylard, a former director of South Africa’s Hartebeeshoek Radio Astronomy Observatory who died in 2014.

    3
    Hartebeeshoek Radio Astronomy Observatory, located near Johannesburg in South Africa.

    During two years of repairs to the observatory’s telescope, Gaylard used Google Maps to scour the continent for old telecommunications dishes. When he saw the Kuntunse dish, he realized that it — and others like it — could be converted for astronomy.

    The switch has been difficult, says Chibueze. New telescopes are designed and built to set specifications, but during work on the Kuntunse dish, engineers and scientists have had to adapt their plans. And there have been issues with the stability of electrical power and Internet supply.

    The conversion has been in large part funded by South Africa, whose African Renaissance and International Co-Operation Fund and department of science and technology have contributed 122 million rand (US$9 million) to the project. From South Africa’s point of view, the AVN would help to prepare the continent for the SKA: many hundreds of dishes, and even more antennas, are set to be built in Australia and South Africa. By the late 2020s, the SKA project also plans to construct other stations — separate from the AVN — in eight other African nations.

    Later this year, the AVN project and South Africa’s SKA project office will be amalgamated into the South African Radio Astronomy Observatory, a unit of the National Research Foundation. The plan, however, is that Ghana and other African nations will ultimately own and operate their AVN telescopes.

    South Africa hasn’t said whether it will fund further conversions. VenKAT says that it needs cost-sharing commitments from other African nations. “We must ensure the governance set-up is in place before we go in for the engineering,” he says. “It’s not just a South African do-and-deliver, but a joint programme.”

    See the full article here .

    [I cannot refrain from commenting that there is all sorts of radio astronomy planning going on all over the world as our NSF begins to defund efforts here with GBO, Arecibo, etc., and the EU has just committed €10 Billion (or is it million, it does not matter, it is the thought that counts) for radio astronomy. It is just like when we defunded the Superconducting Super Collider in Waxahachie, TX, USA and handed off HEP, and thus Higgs, to CERN in Europe.]

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    Nature is a weekly international journal publishing the finest peer-reviewed research in all fields of science and technology on the basis of its originality, importance, interdisciplinary interest, timeliness, accessibility, elegance and surprising conclusions. Nature also provides rapid, authoritative, insightful and arresting news and interpretation of topical and coming trends affecting science, scientists and the wider public.

     
  • richardmitnick 2:41 pm on April 12, 2017 Permalink | Reply
    Tags: , , , , , , Planetary body 2014 UZ224 more informally known as DeeDee, Radio Astronomy   

    From ALMA: “ALMA Investigates ‘DeeDee,’ a Distant, Dim Member of Our Solar System” 

    ESO/NRAO/NAOJ ALMA Array
    ESO/NRAO/NAOJ ALMA Array in Chile in the Atacama at Chajnantor plateau, at 5,000 metres
    ALMA

    April 12, 2017
    Nicolás Lira T.
    Press Coordinator
    Joint ALMA Observatory
    Santiago, Chile
    Tel: +56 2 24 67 65 19
    Cell: +56 9 94 45 77 26
    Email: nicolas.lira@alma.cl

    Charles E. Blue
    Public Information Officer
    National Radio Astronomy Observatory
    Charlottesville, Virginia, USA
    Tel: +1 434 296 0314
    Cell: +1 202 236 6324
    E-mail: cblue@nrao.edu

    Richard Hook
    Public Information Officer, ESO

    Garching bei München, Germany

    Tel: +49 89 3200 6655

    Cell: +49 151 1537 3591
    Email: rhook@eso.org

    Masaaki Hiramatsu

    Education and Public Outreach Officer, NAOJ Chile
    Observatory
Tokyo, Japan

    Tel: +81 422 34 3630

    E-mail: hiramatsu.masaaki@nao.ac.jp
    1
    Artist concept of the planetary body 2014 UZ224, more informally known as DeeDee. ALMA was able to observe the faint millimeter-wavelength “glow” emitted by the object, confirming it is roughly 635 kilometers across. At this size, DeeDee should have enough mass to be spherical, the criterion necessary for astronomers to consider it a dwarf planet, though it has yet to receive that official designation. Credit: Alexandra Angelich (NRAO/AUI/NSF)

    Using the Atacama Large Millimeter/submillimeter Array (ALMA), astronomers have revealed extraordinary details about a recently discovered far-flung member of our solar system, the planetary body 2014 UZ224, more informally known as DeeDee.

    2
    ALMA image of the faint millimeter-wavelength “glow” from the planetary body 2014 UZ224, more informally known as DeeDee. At three times the distance of Pluto from the Sun, DeeDee is the second most distant known TNO with a confirmed orbit in our solar system. Credit: ALMA (ESO/NAOJ/NRAO)

    At about three times the current distance of Pluto from the Sun, DeeDee is the second most distant known trans-Neptunian object (TNO) with a confirmed orbit, surpassed only by the dwarf planet Eris. Astronomers estimate that there are tens-of-thousands of these icy bodies in the outer solar system beyond the orbit of Neptune.

    The new ALMA data reveal, for the first time, that DeeDee is roughly 635 kilometers across, or about two-thirds the diameter of the dwarf planet Ceres, the largest member of our asteroid belt. At this size, DeeDee should have enough mass to be spherical, the criterion necessary for astronomers to consider it a dwarf planet, though it has yet to receive that official designation.

    “Far beyond Pluto is a region surprisingly rich with planetary bodies. Some are quite small but others have sizes to rival Pluto, and could possibly be much larger,” said David Gerdes, a scientist with the University of Michigan and lead author on a paper appearing in the Astrophysical Journal Letters. “Because these objects are so distant and dim, it’s incredibly difficult to even detect them, let alone study them in any detail. ALMA, however, has unique capabilities that enabled us to learn exciting details about these distant worlds.”

    Currently, DeeDee is about 92 astronomical units (AU) from the Sun. An astronomical unit is the average distance from the Earth to the Sun, or about 150 million kilometers. At this tremendous distance, it takes DeeDee more than 1,100 years to complete one orbit. Light from DeeDee takes nearly 13 hours to reach Earth.

    Gerdes and his team announced the discovery of DeeDee in the fall of 2016. They found it using the 4-meter Blanco telescope at the Cerro Tololo Inter-American Observatory in Chile as part of ongoing observations for the Dark Energy Survey, an optical survey of about 12 percent of the sky that seeks to understand the as-yet mysterious force that is accelerating the expansion of the universe.

    The Dark Energy Survey produces vast troves of astronomical images, which give astronomers the opportunity to also search for distant solar system objects.

    The initial search, which includes nearly 15,000 images, identified more than 1.1 billion candidate objects. The vast majority of these turned out to be background stars and even more distant galaxies. A small fraction, however, were observed to move slowly across the sky over successive observations, the telltale sign of a TNO.

    One such object was identified on 12 separate images. The astronomers informally dubbed it DeeDee, which is short for Distant Dwarf.

    The optical data from the Blanco telescope enabled the astronomers to measure DeeDee’s distance and orbital properties, but they were unable to determine its size or other physical characteristics. It was possible that DeeDee was a relatively small member of our solar system, yet reflective enough to be detected from Earth. Or, it could be uncommonly large and dark, reflecting only a tiny portion of the feeble sunlight that reaches it; both scenarios would produce identical optical data.

    Since ALMA observes the cold, dark universe, it is able to detect the heat – in the form of millimeter-wavelength light – emitted naturally by cold objects in space. The heat signature from a distant solar system object would be directly proportional to its size.

    “We calculated that this object would be incredibly cold, only about 30 degrees Kelvin, just a little above absolute zero,” said Gerdes.

    While the reflected visible light from DeeDee is only about as bright as a candle seen halfway the distance to the moon, ALMA was able to quickly home in on the planetary body’s heat signature and measure its brightness in millimeter-wavelength light.

    This allowed astronomers to determine that it reflects only about 13 percent of the sunlight that hits it. That is about the same reflectivity of the dry dirt found on a baseball infield.

    By comparing these ALMA observations to the earlier optical data, the astronomers had the information necessary to calculate the object’s size. “ALMA picked it up fairly easily,” said Gerdes. “We were then able to resolve the ambiguity we had with the optical data alone.”

    Objects like DeeDee are cosmic leftovers from the formation of the solar system. Their orbits and physical properties reveal important details about the formation of planets, including Earth.

    This discovery is also exciting because it shows that it is possible to detect very distant, slowly moving objects in our own solar system. The researchers note that these same techniques could be used to detect the hypothesized “Planet Nine” that may reside far beyond DeeDee and Eris.

    “There are still new worlds to discover in our own cosmic backyard,” concludes Gerdes. “The solar system is a rich and complicated place.”

    3

    Orbits of objects in our solar system, showing the current location of the planetary body ‘DeeDee’.
    Credit: Alexandra Angelich (NRAO/AUI/NSF)

    Additional information

    This research is presented in a paper titled “Discovery and physical characterization of a large scattered disk object at 92 AU,” appearing in the Astrophysical Journal Letters.

    The Atacama Large Millimeter/submillimeter Array (ALMA), an international astronomy facility, is a partnership of the European Organisation for Astronomical Research in the Southern Hemisphere (ESO), the U.S. National Science Foundation (NSF) and the National Institutes of Natural Sciences (NINS) of Japan in cooperation with the Republic of Chile. ALMA is funded by ESO on behalf of its Member States, by NSF in cooperation with the National Research Council of Canada (NRC) and the National Science Council of Taiwan (NSC) and by NINS in cooperation with the Academia Sinica (AS) in Taiwan and the Korea Astronomy and Space Science Institute (KASI).

    ALMA construction and operations are led by ESO on behalf of its Member States; by the National Radio Astronomy Observatory (NRAO), managed by Associated Universities, Inc. (AUI), on behalf of North America; and by the National Astronomical Observatory of Japan (NAOJ) on behalf of East Asia. The Joint ALMA Observatory (JAO) provides the unified leadership and management of the construction, commissioning and operation of ALMA.

    See the full article here .

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    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)*.

    ALMA Array

    NRAO ALMA

    GBO radio telescope, Green Bank, West Virginia, USA
    Green Bank Observatory radio telescope, Green Bank, West Virginia, USA, formerly supported by NSF, but now on its own
    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 3:40 pm on April 10, 2017 Permalink | Reply
    Tags: , , , , Radio Astronomy,   

    From NJIT: Putting Students Closer to Explosive Solar Events 

    NJIT Bloc

    New Jersey Institute of Technology

    1

    April 6, 2017

    NJIT has a long-established reputation as a leader in researching phenomena originating on the star closest to Earth — the Sun. NJIT’s optical telescope at Big Bear Solar Observatory and radio telescope array at Owens Valley, both in California, have greatly expanded our understanding of solar events that periodically impact our home planet, events such as solar flares and coronal mass ejections (CMEs) that can disrupt terrestrial communications and power infrastructure in addition to other effects.

    NJIT Big Bear Solar Observatory, located on the north side of Big Bear Lake in the San Bernardino Mountains of southwestern San Bernardino County, California, approximately 120 kilometers east of downtown Los Angeles

    Ten antennas of NJIT’s 13-antenna Expanded Owens Valley Solar Array (EOVSA)

    Under the auspices of the university’s Center for Solar-Terrestrial Research (CSTR), NJIT investigators are collaborating with colleagues in the U.S. and other countries to gain even more critical knowledge of solar physics. It’s knowledge essential not only for better basic understanding of the Sun but also to improve prediction of the solar explosions that threaten our technologies and to devise better countermeasures.

    What’s more, NJIT researchers are committed to fully engaging students in the search for this knowledge — researchers like Assistant Professor of Physics Bin Chen, who joined the NJIT faculty in 2016. Chen was recently awarded a five-year CAREER grant totaling more than $700,000 by the National Science Foundation (NSF). The NSF’s Faculty Early Career Development (CAREER) program offers the foundation’s most prestigious awards in support of younger faculty who, in building their academic careers, have demonstrated outstanding potential as both educators and researchers.

    Chen completed his Ph.D. at the University of Virginia in 2013 with a focus on solar radio astronomy. His Ph.D. advisor introduced him to fellow solar astronomer, and now NJIT colleague, Distinguished Professor of Physics Dale Gary. Through his acquaintance with Gary, and the opportunity to collaborate on a research project using observational data from NJIT’s Owens Valley Solar Array, Chen learned about the university’s leading-edge efforts in solar radio physics. But before he joined NJIT after receiving his doctorate, Chen added to his research experience through a postdoctoral fellowship under NASA’s Living With a Star program and as an astrophysicist at the Harvard Smithsonian Center for Astrophysics, where he worked on space missions dedicated primarily to solar science.

    Shocking Insights

    Although not yet fellow faculty members at NJIT, Chen and Gary did collaborate with researchers from the National Radio Astronomy Observatory, the University of California, the University of Applied Sciences and Arts Northwestern Switzerland and the University of Minnesota on an article for the journal Science published in 2015, Particle Acceleration by a Solar Flare Termination Shock. The article presented radio imaging data that provides new insights into how a phenomenon known as termination shock associated with solar flares, the most powerful explosions in the solar system, helps to accelerate energetic electrons in the flares to relativistic speeds — propelling these particles into space at nearly the speed of light.

    Chen is now continuing this investigation at NJIT. “There is a lot we don’t know about the ‘inside’ of these solar explosions and how they release so much energy so quickly and so catastrophically,” he says. “For example, how is the energy stored and suddenly released, often in a matter of seconds?

    “The relativistic particle acceleration that we are also studying as part of this research is a process taking place across the universe and is a phenomenon associated with, for example, the massive star explosions known as supernovae. The Sun is a good place to research this phenomenon because its nearness in astronomical terms allows us to acquire a volume of high-resolution data impossible to obtain from observing vastly more distant stars.”

    For his research, Chen is drawing on streams of radio data from a number of sources. In addition to NJIT’s radio observatory at Owens Valley, these include the Karl G. Jansky Very Large Array in New Mexico operated by the National Radio Astronomy Observatory and the Atacama Large Millimeter/Submillimeter Array in Chile.

    NRAO/VLA, on the Plains of San Agustin fifty miles west of Socorro, NM, USA

    ESO/NRAO/NAOJ ALMA Array in Chile in the Atacama at Chajnantor plateau, at 5,000 metres

    Recent upgrades at Owens Valley put it at the forefront of this research as a “new-generation” radio telescope. Another very important advantage afforded by Owens Valley, as Chen emphasizes, is that it is a facility dedicated full-time to solar research.

    Chen is one of the few researchers seeking new knowledge of the Sun by taking advantage of an observing technique called dynamic spectroscopy imaging. This technique allows capturing an image of the Sun every 50 milliseconds at more than a thousand frequencies, and at two different polarizations. This adds up to 40,000 images per second and terabytes of raw data in a day that can be converted into 3D images with resolution far greater than previously obtainable. “This gives us the potential to learn so much more about what is going on in the heart of solar explosions,” Chen says.

    Beyond greater understanding of the fundamental physics involved, Chen adds that his research is very much supportive of the goals of the U.S. National Space Weather Strategy and Action Plan, which reflects critical awareness of how space weather generated by solar phenomena impacts many aspects of terrestrial life and infrastructure. He says, “Solar flares and CMEs are the main drivers of space weather. Better understanding of these drivers is essential for better prediction of such events and the implementation of protective measures.”

    Bringing the Sun to Campus

    In Chen’s estimation, NJIT is uniquely experienced in building, operating and maintaining facilities dedicated to radio observation of the Sun. Potentially, for students, this presents exceptional opportunities to learn at the frontier of the many disciplines relevant to investigating the Sun in the radio spectrum — including hands-on familiarity with the equipment involved. While a limited number of students do have a chance to work at Owens Valley, as well as at Big Bear, distance and lack of appropriate accommodations prevent many more from participating in solar research on site. That’s why Chen also plans to apply a portion of his CAREER funding to creating a Solar Radio Laboratory on campus in Newark.

    “The idea behind the Solar Radio Laboratory is to have a facility on campus with the same state-of-the-art technology found at Owens Valley, just without the antennas,” Chen explains. “We’ll have all the electronics, the radio technology, the data-science capability for processing data streaming from California. This will give students the same hands-on opportunities for working and experimenting with the instrumentation that NJIT has at Owens Valley, instrumentation that is really unique in the United States. Another goal is to use this as a test bed for future improvements at Owens Valley, and to engage students in developing those improvements.”

    For Chen, a complementary educational goal is to also advance the Hale COLLAborative Graduate Education (COLLAGE) program in solar physics, which commemorates the name of the pioneering American solar astronomer George Ellery Hale. There are very few graduate programs in this field in the U.S. and the necessary faculty and physical resources are widely distributed across educational institutions as well as geography. To address this situation, Philip Goode, NJIT distinguished research professor of physics and former CSTR director, proposed that NJIT join with the University of Colorado-Boulder and several other institutions that had solar physics programs in what is now known as the COLLAGE program.

    “COLLAGE gives more students in different parts of the country access to the instruction and resources that allow them to complete master’s and Ph.D. degrees in solar physics,” Chen says. “I am already working with some 20 students, and that’s actually quite a large number for our field. But not only are we increasing opportunities to study solar physics at the graduate level, we’re learning more about coordinating resources among schools and teaching effectively online, which will benefit students who want to study many different complex subjects.”

    See the full article here .

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    NJIT campus

    Welcome to the New Jersey Institute of Technology. We’re proud of our 130 years of history, but that’s only the beginning of our story – we’ve doubled the size of our campus in the last decade, pouring millions into major new research facilities to give our students the edge they need in today’s demanding high-tech marketplace.

    NJIT offers 125 undergraduate and graduate degree programs in six specialized schools instructed by expert faculty, 98 percent of whom hold the highest degree in their field.

    Our academic programs are fully accredited by the appropriate accrediting boards, commissions and associations such as Middle States, ABET, and NAAB.

     
  • richardmitnick 2:13 pm on April 5, 2017 Permalink | Reply
    Tags: , , Radio Astronomy, Spring Cleaning in an Infant Star System   

    From ALMA: “Spring Cleaning in an Infant Star System” 

    ESO/NRAO/NAOJ ALMA Array
    ESO/NRAO/NAOJ ALMA Array in Chile in the Atacama at Chajnantor plateau, at 5,000 metres
    ALMA

    03 April 2017
    Nicolás Lira T.
    Press Coordinator
    Joint ALMA Observatory
    Santiago, Chile
    Tel: +56 2 24 67 65 19
    Cell: +56 9 94 45 77 26
    Email: nicolas.lira@alma.cl

    Richard Hook
    Public Information Officer, ESO

    Garching bei München, Germany

    Tel: +49 89 3200 6655

    Cell: +49 151 1537 3591
    Email: rhook@eso.org

    Masaaki Hiramatsu

    Education and Public Outreach Officer, NAOJ Chile
    Observatory
Tokyo, Japan

    Tel: +81 422 34 3630

    E-mail: hiramatsu.masaaki@nao.ac.jp

    Charles E. Blue
    Public Information Officer
    National Radio Astronomy Observatory
    Charlottesville, Virginia, USA
    Tel: +1 434 296 0314
    Cell: +1 202 236 6324
    E-mail: cblue@nrao.edu

    1
    Credit: ALMA (ESO/NAOJ/NRAO)/ Fedele et al.

    This image depicts the dusty disc encircling the young, isolated star HD 169142. The Atacama Large Millimeter/submillimeter Array (ALMA) imaged this disc in high resolution by picking up faint signals from its constituent millimetre-sized dust grains. The vivid rings are thick bands of dust, separated by deep gaps.

    Optimised to study the cold gas and dust of systems like HD 169142, ALMA’s sharp eyes have revealed the structure of many infant solar systems with similar cavities and gaps. A variety of theories have been proposed to explain them — such as turbulence caused by magnetorotational instability, or the fusing of dust grains — but the most plausible explanation is that these pronounced gaps were carved out by giant protoplanets.

    When solar systems form gas and dust coalesce into planets. These planets then effectively spring clean their orbits, clearing them of gas and dust and herding the remaining material into well-defined bands. The deep gaps seen in this image are consistent with the presence of multiple protoplanets — a finding that agrees with other optical and infrared studies of the same system.

    Observing such dusty protoplanetary discs with ALMA allows scientists to investigate the first steps of planet formation in a bid to unveil the evolutionary paths of these infant systems.

    See the full article here .

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    The Atacama Large Millimeter/submillimeter Array (ALMA), an international astronomy facility, is a partnership of Europe, North America and East Asia in cooperation with the Republic of Chile. ALMA is funded in Europe by the European Organization for Astronomical Research in the Southern Hemisphere (ESO), in North America by the U.S. National Science Foundation (NSF) in cooperation with the National Research Council of Canada (NRC) and the National Science Council of Taiwan (NSC) and in East Asia by the National Institutes of Natural Sciences (NINS) of Japan in cooperation with the Academia Sinica (AS) in Taiwan.

    ALMA construction and operations are led on behalf of Europe by ESO, on behalf of North America by the National Radio Astronomy Observatory (NRAO), which is managed by Associated Universities, Inc. (AUI) 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.

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