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  • richardmitnick 7:09 am on June 16, 2015 Permalink | Reply
    Tags: , , , Radio Astronomy   

    From NOVA: “A Window into New Physics” 

    PBS NOVA

    NOVA

    10 Jun 2015
    Kate Becker

    In 2007, David Narkevic was using a new algorithm to chug through 480 hours of archived data collected by the Parkes radio telescope in Australia. The data was already six years old and had been thoroughly combed for the repeating drumbeat signals that come from rapidly-rotating dead stars called pulsars.

    But Narkevic, a West Virginia University undergrad working under the supervision of astrophysicist Duncan Lorimer, was scouring these leftovers for a different animal: single pulses of unusually bright radio waves that are known to punctuate the rhythm of the most energetic pulsars.

    1
    The Parkes Observatory hosts a large radio telescope in central New South Wales, Australia.

    Radio astronomers have an arsenal of well-honed tricks for teasing out faint signals including correcting for “dispersion.” Dispersion is when signals traveling through space arrive slightly earlier at high frequencies than they do at low frequencies according to a precise formula that describes how electromagnetic radiation is delayed by free-floating electrons. The more interstellar stuff the signals have to traverse, the more dispersed they are, so “dispersion measure” functions as a rough proxy for distance.

    Distant, and therefore highly dispersed signals, are difficult to pick up because their energy is smeared out across frequency and time. So, astrophysicists design search algorithms that apply one correction factor after another, with the hope that, by trial and error, they might hit on the right one and pluck a signal out from the noise. The process requires a lot of computing time, so astronomers typically only use common-sense dispersion corrections. But with all the common-sense results already wrung out from the data set, Narkevic was trying out correction factors corresponding to distances far beyond the Milky Way and its neighboring galaxies.

    To his surprise, it worked: He discovered a bright burst of radio waves, lasting less than five milliseconds, coming from a point on the sky a few degrees away from the Small Magellanic Cloud but that seemed to originate from far beyond it.

    2
    NASA/ESA Hubble and Digitized Sky Survey 2

    It was impossible to pin down its precise location and distance but, based on the dispersion, Lorimer and his team calculated that it had to be far: billions of light years beyond the Milky Way.

    Lorimer’s team trained the Parkes telescope on the site for 90 more hours but never picked up another burst. Whatever Narkevic had found, it didn’t look like one of the pulsar pulses Lorimer had originally set out to find.

    That left plenty of other possibilities. It could be some human-made interference masquerading as a mysterious cosmic object: military radar, microwave ovens, bug zappers, and even electric blankets all produce electromagnetic radiation that can confuse readings from radio telescopes. But the “Lorimer burst” didn’t look like it was coming from one of these sources. For one thing, the dispersion was by-the-book: that is, the signal “swept” in at high frequencies first, and low frequencies later. For another, it was picked up by just three of the telescope’s 13 “beams,” each of which corresponds to a single pixel on a sky map, suggesting that it was localized out there, somewhere in the sky, rather than coming from a nearby source of interference, which would swamp the whole telescope.

    “We couldn’t think of any radio-frequency interference that would mimic those characteristics,” says astrophysicist Maura McLaughlin, also of West Virginia University, who was part of the discovery team. The researchers also ruled out some of the usual cosmic suspects: The burst was too bright to be a spasmodic eruption from a pulsar and too high-frequency to be the radio counterpart to a gamma-ray burst. Magnetars, highly magnetized neutron stars that sizzle with X-rays and gamma-rays, remained a strong possibility. “I tend to go with the least exotic things,” McLaughlin says, citing Occam’s razor: “The simplest thing is always the best. But I wouldn’t be surprised if it was something really strange and exotic, too.”

    Such observational puzzles are candy for theorists, and fast radio bursts, or FRBs as they are called, present a particularly sweet mystery: Their extreme properties hint that they might be able to reveal phenomena that push the boundaries of known physics, perhaps probing the properties of dark matter or quantum gravity theories beyond the Standard Model.

    3
    Standard Model of Particle Physics. The diagram shows the elementary particles of the Standard Model (the Higgs boson, the three generations of quarks and leptons, and the gauge bosons), including their names, masses, spins, charges, chiralities, and interactions with the strong, weak and electromagnetic forces. It also depicts the crucial role of the Higgs boson in electroweak symmetry breaking, and shows how the properties of the various particles differ in the (high-energy) symmetric phase (top) and the (low-energy) broken-symmetry phase (bottom).

    So while observational astronomers kept searching for more FRBs, theorists began speculating about what they might be.

    Imploding Neutron Stars

    There were three clues: The burst was short, powerful, and distant. To astrophysicists, a short signal points to a small source—in this case, one so small that a light beam could cross it in the duration of the burst, just a few milliseconds. That means that FRB “progenitors,” whatever they are, probably measure less than one thousandth the width of the sun. What could pack such a huge amount of energy into that tiny package? “The only things that can produce that much energy are neutron stars and black holes,” says Jim Fuller, a theorist at Caltech.

    Fuller started thinking seriously about fast radio bursts in 2014, just as they were enjoying a scientific comeback. Studies of the Lorimer burst had languished for years after a group led by Sarah Burke-Spolaor, then a postdoc at the Commonwealth Scientific and Industrial Research Organisation in Australia, detected 16 similar bursts and was able to unambiguously chalk them up to earthly interference. But then, in 2013, Burke-Spolaor found a Lorimer burst of her own. A handful more followed. FRBs were back from the dead.

    Meanwhile, Fuller had a different astronomical mystery on his mind: the apparent scarcity of pulsars near the center of the Milky Way. There should be plenty of pulsars within a few light years of the galactic center, Fuller says, but despite years of searching, astronomers have found just one. What happened to the rest of them? Astrophysicists call this the “missing pulsar problem.”

    2
    The FRBs seemed to be coming from a few degrees away from the Small Magellanic Cloud.

    Last year, a pair of astronomers proposed an unconventional answer: those missing pulsars might have “imploded” under the weight of dark matter, which is abundant in the center of the galaxy. Though dark matter passes easily through planets and stars, it could get trapped in the dense meat of a neutron star, they argued. Once there, it would slowly sink down to the star’s center. Over time, dark matter would pile up in the core, eventually collapsing into a tiny black hole that would eat away at the neutron star from the inside out. The star would gradually erode over thousands or millions of years until, in one great slurp, the black hole would devour nearly the whole mass of the neutron star in a matter of milliseconds.

    “Probably, it will be a very violent event, where the magnetic field is totally expelled from the black hole and reconnects with itself,” Fuller says. Some of the energy of the ravaged magnetic field would be turned into electromagnetic radiation: a blast of radio waves that might look a lot like an FRB.

    “It’s a pretty crazy idea,” Fuller admits. But it does make some predictions that we can observe. If Fuller’s model is right, neutron star implosions should have left behind lots of small black holes near the center of the galaxy, each holding about one-and-a-half times the mass of our sun. Though astronomers can’t see a black hole directly, if the black hole happens to be drawing matter from a companion star, as is relatively common, it will give off characteristic bursts of X-rays. A different kind of X-ray burst, on the other hand, could signal the presence of a neutron star, not a black hole. If there are lots of neutron stars hanging out around the galactic center, that would challenge Fuller’s scenario. (Some recent X-ray observations point toward the existence of those neutron stars, though the evidence is not yet definitive, Fuller says.)

    Fuller’s argument also predicts that FRBs should be coming from very close to the center of other galaxies. So far, astronomers haven’t pinpointed the location of a single FRB, and localizing one within a galaxy is an added challenge.

    If Fuller’s predictions hold up, they will yield fresh insight into the nature of dark matter, which is still almost totally a blank. First, it will mean that dark matter particles don’t annihilate each other, as some recent observations have hinted. It would also reveal dark matter’s “cross section”—that is, the likelihood that a particle of dark matter will interact with normal matter, as opposed to passing straight through it. For the neutron star implosion scenario to hold up, dark matter’s cross section must be just somewhere in a very narrow range of possibilities, Fuller says.

    Bouncing Black Holes

    Another possibility for what’s causing FRBs comes from the leading edge of black hole physics, where theorists are puzzling over the difficult answer to an apparently simple question: What happens to the stuff that falls into a black hole? Physicists once thought that it was inevitably compressed into an infinitely small, infinitely dense point called a singularity. But because the known laws of physics break down at this point, the singularity has always been a raw nerve for physicists.

    Many physicists would like to find a way to sidestep the singularity, and theorists working on a theory called loop quantum gravity think they have found a way to do so. Loop quantum gravity proposes that the fabric of spacetime is woven of tiny—you guessed it—loops. These loops can’t be compressed indefinitely—push them too far, and they push back. In the universe of loop quantum gravity, a would-be black hole can collapse only until gravity is overcome by the outward pressure generated by the loops, which then hurtles the black hole’s innards back out into space, transforming it into its mathematical opposite, a white hole.

    Abruptly, the contents of the black hole would be converted into a tremendous blast of energy concentrated at a wavelength of a few millimeters, according to Carlo Rovelli, a theorist at Aix-Marseille University, and his colleagues in France and the Netherlands. We might be able to pick up the first of these cosmic kabooms today, coming from some of the universe’s earliest black holes, Rovelli says, and they might look a lot like fast radio bursts. It’s not a perfect match: fast radio bursts emit at a lower frequency, corresponding to a wavelength of about 20 centimeters, and they don’t give off as much energy as the theorists predict for a “quantum bounce.” But, Rovelli says, the model’s predictions are still very crude and don’t account for the black hole’s motion, interactions between the matter it contains, or even the fact that the black hole has mass.

    Rovelli says the model does make one clear, testable prediction: a peculiar correlation between the wavelength at which the signal is received and the distance to the black hole. That’s because the wavelength of the emitted energy depends on two things: the size of the black hole and its distance from Earth. The most distant explosions should be coming from the youngest, and therefore smallest, black holes, meaning that their energy will be skewed toward shorter wavelengths. But as the radiation travels across the expanding universe, it will be stretched out, or “redshifted,” so that the signals we pick up on Earth register at a longer wavelength than they were emitted. Add up the effects and you should see the specific curve that Rovelli and his colleagues predict. As astronomers find more fast radio bursts, they will be able to test whether they match the predicted curve.

    It may sound like a long shot. But, if it’s right, the payoff would be huge: “If the observed Fast Radio Bursts are connected to this phenomenon, they represent the first known direct observation of a quantum gravity effect,” wrote Rovelli and his colleagues.

    It could also get physicists out of a theoretical jam called the black hole information paradox, which pits two unshakable tenets of physics against each other. On one side, the principle of unitarity holds that information can never be lost; on the other, according to the rules of black hole thermodynamics, the only thing that ever escapes from a black hole, Hawking radiation, is randomly scrambled and preserves no information. To solve the paradox, some physicists have proposed that the entanglement between incoming particles and those radiated out as Hawking radiation could be spontaneously broken, putting up a “firewall” of energy at the black hole’s horizon. But the concept is still controversial: plenty of ideas in modern physics violate our intuition about how the world is supposed to work, but a sizzling wall of energy floating around a black hole? Really?

    The quantum bounce effect could resolve the information paradox and neutralize the need for a firewall, argue Rovelli and his colleagues. The information inside the black hole isn’t lost: it just comes out later.

    Superconducting Cosmic Strings

    Fast radio bursts could also be a modern manifestation of something that happened 13.7 billion years ago, just after the Big Bang, when the baby universe was roiling with so much energy that all the fundamental physical forces acted as one. At this moment, the Higgs field had not yet switched on and nothing in the universe had mass. Then, on came the Higgs field, unfurling through space and pinging every particle it encountered with its magic wand, bestowing the gift of mass.

    Some theorists think that the field associated with the Higgs boson, discovered in 2012 at the Large Hadron Collider [LHC], is just one of many similar fields, each of which plays a role in giving particles mass.

    CERN LHC Map
    CERN LHC Grand Tunnel
    CERN LHC particles
    LHC

    But many models predict that these fields would not diffuse perfectly through all of space. Instead, they would miss a few spots. These gaps, the thinking goes, would become defects called cosmic strings, skinny tubes of space that, like springy rubber bands, are tense with stored energy. Extending over millions of light years and traveling close to the speed of light, these hypothetical strings would be so massive that a single centimeter-long snippet would contain a mountain’s-worth of mass, says Tanmay Vachaspati, a physicist at Arizona State University who, along with Alexander Vilenkin at Tufts University, did early work on the formation and evolution of cosmic strings.

    Invisible to most telescopes, cosmic strings could be detected via the gravitational waves they emit as they shimmy through space and crash into other cosmic strings. So far, astronomers haven’t made any affirmative detection of these gravitational waves, though the fact that they haven’t shown up yet allows physicists to put some limits on the maximum mass of the strings.

    A still-more-exotic breed of cosmic strings called superconducting cosmic strings, which carry an electrical current, could turn out to be easier for astronomers to observe. First proposed by theorist Edward Witten, these electrified strings should give off detectable electromagnetic radiation as they move through space, Vachaspati says. The emission would look like a constant hum of very-low-frequency radio waves, occasionally spiked with brief, higher-frequency bursts from dramatic events called kinks and cusps. Kinks happen when two strings meet and reconnect at their point of intersection, Vachaspati says. Cusps are like the end of a whip, lashing out into space at close to the speed of light. What, exactly, their radio emission might look like depends on many still-unknown parameters of the strings, Vachaspati says. But it is possible that they would look very much like fast radio bursts.

    There is one problem, though. Vachaspati and his colleagues predict that the radio emission from superconducting cosmic strings should be linearly polarized: that is, it should oscillate in a plane. So far, polarization has only been measured for one fast radio burst, but that was circularly polarized, meaning that its electric field draws out a spiral around the direction its traveling.

    Some theorists, including Vilenkin, think it might be possible for a superconducting cosmic string to produce a circularly polarized signal under certain conditions. And with polarization measured for just one FRB so far, it’s too soon to discount the hypothesis entirely.

    Future Observations

    Today, astronomers have detected about a dozen fast radio bursts. (A group of apparently similar signals, curiously clustered around lunchtime, were recently traced to a more mundane source: the Parkes observatory microwave oven.) But observers and theorists in every camp agree on this: to figure out what is causing FRBs, they need to find more of them.

    “Right now, there are far more theories about what’s causing FRBs than FRBs themselves,” says Burke-Spolaor, who is now leading up a search for FRBs with the Very Large Array (VLA), a network of radio telescopes in New Mexico.

    NRAO VLA
    NRAO VLA

    With more bursts in their catalog, astronomers will be able to draw more meaningful conclusions about how common FRBs are and how they are distributed across the sky. They will also be able to answer two critical questions: where the bursts are coming from, and what they look like in other parts of the electromagnetic spectrum.

    So far, astronomers have localized each Parkes burst to a disc of sky that’s about a half-degree across—about the size of the full moon. To astronomers, that’s an enormous region: extend your vision out to the distance at which FRBs are expecting to be going off, and that little patch of sky could contain hundreds of galaxies. Using the VLA, Burke-Spolaor should be able to pin down a burst’s location to a single galaxy. But first, she has to find one. Based on the number of FRBs that have been seen so far, she estimates that it will take about 600 hours of skywatching to have a solid chance of observing one. So far, she has a little under 200 hours down.

    Unlike the archival search that turned up the first FRB, Burke-Spolaor’s search campaign is attempting to catch FRBs in the act. That will give astronomers a chance to quickly swivel other telescopes to the same spot and potentially see the bursts giving off energy at other wavelengths. So far, only three FRBs have been caught in real time, including a May 14, 2014, burst observed at Parkes by a team of astronomers including Emily Petroff, a PhD student in astrophysics at Swinburne University of Technology in Melbourne, Australia. Within a few hours, a dozen other telescopes were watching the source of the burst at wavelengths ranging from X-rays to radio waves. But not one of them saw anything unusual. Papers on two more bursts, observed in February and April of this year, are currently being prepared for publication; astronomers followed up on those bursts with observations at multiple wavelengths, too, but haven’t yet announced the result of those studies.

    Meanwhile, Jayanth Chennamangalam, a former student of Lorimer’s who is now a post-doc at Oxford, is putting the finishes touches on a system that will scan every 100 microseconds of incoming radio data at the Arecibo dish in Puerto Rico for sudden, short pulses.

    Arecibo
    Arecibo

    The system, called ALFABURST, will piggyback on the latest iteration of SERENDIP, a spectrometer that’s been tapping the Arecibo’s feed for years, listening for signals from extraterrestrial civilizations. Ultimately, it will be able to alert astronomers to unusual bursts within seconds—fast enough for rapid follow-up at other wavelengths.

    Will fast radio bursts turn out to be a window into new physics or just a new perspective on something more familiar? It’s too early to say. But for now, researchers can relish the moment of being maybe, just possibly, on the verge of finding something genuinely new to science.

    See the full article here.

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    NOVA is the highest rated science series on television and the most watched documentary series on public television. It is also one of television’s most acclaimed series, having won every major television award, most of them many times over.

     
  • richardmitnick 8:28 am on June 6, 2015 Permalink | Reply
    Tags: , , Center for Astrophysics, Radio Astronomy   

    From CfA: “The Ages of Extragalactic Jets” 

    Smithsonian Astrophysical Observatory
    Smithsonian Astrophysical Observatory

    June 5, 2015
    No Writer Credit

    1
    The bright radio galaxy NGC 4261 as seen in visible light (white) and radio (orange), showing a pair of opposed jets emanating from the nucleus. Astronomers have determined that the lobes are about thirty million years old, and were produced from multiple outbursts from around the nuclear black hole. Wide-Field and Planetary Camera of the Hubble Space Telescope, and National Radio Astronomy Observatory.

    The longest known highly collimated structures in the universe are the narrow jets that emanate from the vicinity of powerful black holes in certain types of galactic nuclei. These narrow beams, often in pairs propagating in opposite directions, can stretch across millions of light-years. They transport huge amounts of energy from the nuclear black hole regions where they originate into intergalactic space. The jets were discovered at radio wavelengths but they emit at X-ray wavelengths as well because the electrons in the jets move at close to the speed of light. These galaxies are active areas of research both because they are among the most energetic phenomena in the universe and because they are the primary mechanism that injects energy into the clusters of galaxies in which these radio monsters reside.

    The development of these jets, their ages, and their ultimate dispositions are only vaguely understood. Astronomers suspect their lives have three phases, starting with the supersonic inflation of lobes of hot gas around the particle jets. It appears that in most sources this first phase is brief. Afterwards, the lobes expand gradually until their internal temperatures and pressures drop down to the values of the ambient gas. In the final phase, the jet ejection mechanisms shut down and the associated lobes become unobservable. There are numerous examples of galaxies at these various stages that provide the basis for these notions.

    CfA astronomers Ewan O’Sullivan, Diana Worrall, and Mark Birkinshaw, together with four colleagues, examined the jets in the powerful radio galaxy 3C270 (also known as NGC 4261).

    2
    A Hubble Space Telescope (HST) image of the gas and dust disk in the active galactic nucleus of NGC 4261. Credit: HST/NASA/ESA.

    NASA Hubble Telescope
    NASA/ESA Hubble

    This source has its brightest radio emission knots closest to the black hole nucleus (the other common type of radio jet galaxy has its brightest regions farthest away from the nucleus). The projected linear scale for the lobes in this source is about 250 thousand light-years at its maximum extent. The scientists used new and archival radio observations of the lobes, taken at twelve different wavelengths, combined with X-ray observations, to model the emission mechanisms throughout the lobes more precisely than previously done. The multi-wavelength data allow them to map how the character of the emission (i.e., its relative strength at different wavelengths) varies, and to model those variations. They conclude that the two lobes are respectively about twenty-nine and thirty-seven million years old, contrary to the conventional wisdom that they are about twice as old based on dynamical models. They also conclude that the lobes are the result of multiple outbursts of activity from the vicinity of black hole. The total energy needed to heat these lobes is stupendous, roughly equivalent to the Sun’s total power output over a million billion years, more than the age of the universe.

    Reference(s):

    New Insights into the Evolution of the FR I Radio Galaxy 3C 270 (NGC 4261) from VLA and GMRT Radio Observations, Kolokythas, Konstantinos, O’Sullivan, Ewan, Giacintucci, Simona, Raychaudhury, Somak, Ishwara-Chandra, C. H., Worrall, Diana M., Birkinshaw, Mark, MNRAS, 450, 1732, 2015.

    NRAO VLA
    NRAO VLA

    Giant Metrewave Radio Telescope
    GMRT, Maharashtra, INDIA

    See the full article here.

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    About CfA

    The Center for Astrophysics combines the resources and research facilities of the Harvard College Observatory and the Smithsonian Astrophysical Observatory under a single director to pursue studies of those basic physical processes that determine the nature and evolution of the universe. The Smithsonian Astrophysical Observatory (SAO) is a bureau of the Smithsonian Institution, founded in 1890. The Harvard College Observatory (HCO), founded in 1839, is a research institution of the Faculty of Arts and Sciences, Harvard University, and provides facilities and substantial other support for teaching activities of the Department of Astronomy. The long relationship between the two organizations, which began when the SAO moved its headquarters to Cambridge in 1955, was formalized by the establishment of a joint center in 1973. The CfA’s history of accomplishments in astronomy and astrophysics is reflected in a wide range of awards and prizes received by individual CfA scientists.

    Today, some 300 Smithsonian and Harvard scientists cooperate in broad programs of astrophysical research supported by Federal appropriations and University funds as well as contracts and grants from government agencies. These scientific investigations, touching on almost all major topics in astronomy, are organized into the following divisions, scientific departments and service groups.

     
  • richardmitnick 3:43 pm on June 1, 2015 Permalink | Reply
    Tags: , , , Radio Astronomy   

    From Dunlap: “Distant Radio Galaxies Reveal Hidden Structures Right Above Our Heads” 

    Dunlap Institute bloc
    Dunlap Institute for Astronomy and Astrophysics

    1 June 2015
    Contact details:
    Cleo Loi, University of Sydney, phone +61 2 9114 2289, cell +61 434 980 778, email sloi5113@uni.sydney.edu.au
    Prof Bryan Gaensler, Dunlap Institute for Astronomy & Astrophysics, University of Toronto, cell 416 522 0887, email bgaensler@dunlap.utoronto.ca
    Media:
    Chris Sasaki, Dunlap Institute for Astronomy & Astrophysics, University of Toronto, phone +1 416 978 6613, email csasaki@dunlap.utoronto.ca
    Dr. Wiebke Ebeling, CAASTRO, phone +61 8 9266 9174, cell +61 423 933 444, email wiebke.ebeling@curtin.edu.au
    Verity Leatherdale, University of Sydney, phone +61 2 9351 4312, cell +61 403 067 342, email verity.leatherdale@sydney.edu.au

    1
    Credit: CAASTRO / Mats Björklund (Magipics)

    By observing galaxies billions of light-years away, a team of astronomers has detected tube-like structures mere hundreds of kilometres above the Earth’s surface.

    “For over 60 years, scientists believed these structures existed but by imaging them for the first time, we’ve provided visual evidence that they are really there,” said Cleo Loi of the ARC Centre of Excellence for All-sky Astrophysics (CAASTRO) at the University of Sydney and lead author of a paper published in Geophysical Research Letters last week.

    The astronomers—including Prof. Bryan Gaensler, former director of CAASTRO and the current director of the Dunlap Institute at the University of Toronto—made their observations with the Murchison Widefield Array [MWA].

    SKA Murchison Widefield Array
    MWA

    The MWA is a radio telescope in Western Australia designed to observe the early Universe and distant galaxies, as well as stars and nebulae within our own Milky Way Galaxy.

    As light from a galaxy passes through layers in the Earth’s magnetosphere, the light’s path—and hence the galaxy’s apparent position—is altered by variations in density in the layers. The effect is like looking up from the bottom of a swimming pool at the distortions caused by waves on the surface.

    Mapping the variations in the positions of multiple radio sources over the course of a night revealed the shape and dimensions of the tube structures. As well, by exploiting the MWA’s rapid “snapshot” capabilities, Loi and her colleagues created a movie—effectively capturing the real-time motions of the tubes.

    According to Gaensler, “We were trying to understand if the motions of the ionosphere were random or had a pattern, both to see if the MWA could be used to study the ionosphere, and also to be able to correct for its effect and study the sources behind it.”

    In addition, the astronomers made their observations using the east and west halves of the MWA’s array of antennas as separate instruments. “This is like turning the telescope into a pair of eyes, and by doing that we were able to probe the 3D nature of these structures and watch them move around,” said Loi.

    The observations revealed that the tubes above the MWA are 500 to 700 km above the surface and are aligned with the Earth’s magnetic field. The tubes are at an angle to the surface because they follow the field as it angles down into the planet.

    The insight into our own world is just one part of the accomplishment. According to Gaensler, “This work highlights the new frontier that the MWA is opening up. By operating at low radio frequencies and covering such an enormous field of view, we can study subtle and complicated processes that we had only ever caught fleeting glimpses of previously.”

    See the full article here.

    Please help promote STEM in your local schools.

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    Dunlap Institute campus

    The Dunlap Institute is committed to sharing astronomical discovery with the public. Through lectures, the web, social and new media, an interactive planetarium, and major events like the Toronto Science Festival, we are helping to answer the public’s questions about the Universe.
    Our work is greatly enhanced through collaborations with the Department of Astronomy & Astrophysics, Canadian Institute for Theoretical Astrophysics, David Dunlap Observatory, Ontario Science Centre, Royal Astronomical Society of Canada, the Toronto Public Library, and many other partners.

     
  • richardmitnick 8:32 pm on May 19, 2015 Permalink | Reply
    Tags: , , , , Radio Astronomy   

    From ALMA: “ALMA Reveals the Cradles of Dense Cores: the Birthplace of Massive Stars” 

    ESO ALMA Array
    ALMA

    19 May 2015
    Valeria Foncea
    Education and Public Outreach Officer
    Joint ALMA Observatory
    Santiago, Chile
    Tel: +56 2 467 6258
    Cell: +56 9 75871963
    Email: vfoncea@alma.cl

    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: +1 434.242.9559
    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

    A Taiwanese research team used the Atacama Large Millimeter/submillimeter Array (ALMA) to observe a large molecular gas clump [1] named G33.92+0.11, where a cluster with massive stars is forming. The excellent imaging power of ALMA allowed to reveal with unprecedented detail, the fine structure of the molecular gas at the center of the region, where two surprisingly large molecular gas arms, with sizes of ~ 3.2 light years [2], appear to be spiraling around two massive molecular cores. These results showed that the large molecular arms are indeed the cradles of dense cores, which are current or future birthplaces of massive stars. This is a crucial step forward in the understanding of how mass distributes to form both massive cores and massive stars.

    How the gravitationally bound stellar clusters, for example, the young massive clusters (YMCs) and globular clusters (GCs) come to the existence, remains a fundamental problem in astrophysics. To form such complex systems, it is required that massive amounts of gas can be converted with little losses, into stars, before they start to disperse the gas by the action of their winds —the so called stellar feedback—, and such process is far from trivial. Current models propose that in order to quench the action of stellar feedback, the global collapse of the parent molecular cloud has to be very rapid.

    However, this global collapse of giant [3] molecular clouds (GMC) represents an observational challenge for astronomers, because they cannot measure distances along their line of sight (data is projected in two dimensions) and because it is near impossible to measure gas velocities in the transverse directions. Nevertheless, the amplified effects of the initial rotation (angular momentum) of the clouds may translate into the formation of massive molecular clumps that are supported by centrifugal forces at the center of the collapsing GMC.

    1
    Figure 1: An overview of a massive stellar cluster-forming molecular cloud from numerical hydrodynamical simulations (courtesy from James Dale [5]), and the context of the scale of the ALMA observations for the deeply embedded central few light-years region. Credit: ALMA(ESO/NAOJ/NRAO), H. B. Liu, J. Dale.

    The identification of rotating structures at scales larger than the cores, may serve as evidence of such an outcome of global collapse. Also, because the massive molecular clumps are the densest regions in a collapsing GMC, they are likely the sites where the most massive stars of stellar clusters can form. To resolve the details of the morphology and kinematics of these systems will be key to understand how mass distributes in the sites of star cluster formation, such that it can form both massive and not massive stars.

    A research team led by Hauyu Baobab Liu at the Academia Sinica Institute of Astronomy and Astrophysics (ASIAA) observed with ALMA the luminous OB cluster-forming region G33.92+0.11, located at a distance of about 23.000 lightyears. This source is at a beginning phase of forming an OB association, which has a contained luminosity of 250 thousand times the luminosity of the Sun. Most of this light is provided by a few embedded massive stars. The research team used the archival Herschel 350 μm, which were combined with another 350 μm image from the Caltech Submillimeter Observatory(CSO) with a higher angular resolution.

    Caltech Submillimeter Observatory
    CSO

    “The Herschel Space Telescope archive images provided a high quality map of the 350 μm thermal emission of the external dusty gas structures around G33.92+0.11.

    ESA Herschel
    ESA/Herschel

    We completed the missing small-scale pixels of this map with data from the Caltech Submillimeter Observatory. The final map revealed two molecular arms twisted in opposite directions, north and south of the cluster, converging at the central molecular clumps, indicating that perhaps the gas is being transported toward the central cluster along these spiral arms from distances as large as 20 light years,” says co-author Román-Zúñiga, from the Astronomy Institute of the Universidad Nacional Autónoma de México.

    2
    Figure 2: The central part of the OB cluster-forming region G33.92+0.11, observed by ALMA. Left: Dust continuum image taken at 1.3 mm. Right: False color image showing the integrated emission of three molecules: CH3CN in yellow, 13CS in green, and DCN in magenta, respectively. The CH3CN emission mainly traces the hot molecular cores, which harbor massive stars. The 13CS emission traces warm dense gas and shocks. The DCN emission appears to follow the bulk of dense gas traced by the dust continuum emission. Credit: ALMA(ESO/NAOJ/NRAO), H. B. Liu et al.

    The unprecedented high angular resolution and high imaging fidelity of ALMA allowed the astronomers to reveal in G33.92+0.11 A two centrally located massive molecular cores (~100-300 solar masses), connected by several spiraling dense molecular gas arms. This kind of morphology resembles the previous ALMA images of molecular gas arms surrounding the low-mass protostellar binary L1551 NE [4], however, but linearly scaled-up by a factor between 100 and 1000 (Figure 1). In addition, the observed gas arms in G33.92+0.11 A appear to be fragmenting, which results in the formation of multiple satellite cores orbiting the central two highest mass cores. Comparing the simultaneously observed molecular gas tracers including CH3CN, 13CS, and DCN shows that the gas excitation conditions in these molecular arms and cores far from being uniform across the system (Figure 2). For instance, the two highest mass cores at the center already harbor massive stars and present bright CH3CN emission. The molecular arms embedded with satellite cores in the north may be relatively cool, indicated by the good correlation between the DCN line and the 1.3 mm dust continuum emission. Finally the molecular arms connecting the central massive molecular cores from the west may contain gas that is shocked to a higher temperature or are subject to stellar heating and show stronger 13CS emission.

    This team propose that the central ~1 pc scale region of G33.92+0.11 A is a flattened, massive molecular clump that is currently accreting material, which is being fed by the exterior gas filaments, and is marginally supported by centrifugal forces. At all spatial scales, the regions of higher density, that contain larger amounts of mass, form at the center of the system. Accretion may be prohibited by the angular momentum, but might be alleviated by fragmentation. The authors further propose that in the dense eccentric accretion flows, the formation of spiraling arm-like structures may be essential to the process. The subsequent fragmentation of the dense molecular arms may lead to the formation of the second generation high-mass stars.

    “Gas structures similar to spiral arms should be common in many systems at many different scales, as long as they are unstable to gravity and have non-negligible rotation. The superb images made with ALMA are starting to show this,” says co-author Galván-Madrid.

    Notes

    [1] In our nomenclature, massive molecular clumps refer to dense molecular gas structures with sizes of ∼0.5-1 pc, massive molecular cores refer to the <0.1 pc size overdensities embedded within a clump, and condensations refer to the distinct molecular substructures within a core. Fragmentation refers to the dynamical process that produces or enhances the formation of multiple objects.

    [2] 1 parsec (pc) ~ 3.2 light years ~ 3.086×1016 meters.

    [3] The typical spatial scales of stellar cluster-forming molecular clouds are 101-2 pc.

    [4] More in the press release Dec 04, 2014: Astronomers Identify Gas Spirals as a Nursery of Twin Stars through ALMA Observation

    [5] For details, please see Dale, J. E., Ngoumou, J., Ercolano, B., Bonnell, I. A., 2014, MNRAS, 442, 694

    More information

    These observational results were published in the Astrophysical Journal (ApJ, 804, 37) by Liu et al. as ALMA resolves the spiraling accretion flow in the luminous OB cluster forming region G33.92+0.11.

    This research was conducted by Hauyu Baobab Liu (Academia Sinica Institute of Astronomy and Astrophysics); Roberto Galván-Madrid (Centro de Radioastronomía y Astrofísica, Universidad Nacional Autónoma de México); Izaskun Jiménez-Serra (Department of Physics and Astronomy, University College London and European Southern Observatory, Garching Germany); Carlos Román-Zúñiga (Instituto de Astronomía, Universidad Nacional Autónoma de México); Qizhou Zhang (Harvard-Smithsonian Center for Astrophysics); Zhiyun Li (Department of Astronomy, University of Virginia); Huei-Ru Chen (Institute of Astronomy and Department of Physics, National Tsing Hua University).

    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 8:42 pm on May 11, 2015 Permalink | Reply
    Tags: , , , Radio Astronomy   

    From JPL: “Astronomers Take a New Kind of Pulse From the Sky” 

    JPL

    May 11, 2015
    Media Contact
    Whitney Clavin
    Jet Propulsion Laboratory, Pasadena, Calif.
    818-354-4673
    whitney.clavin@jpl.nasa.gov

    Fast Facts:

    › Enormous telescope array produces videos of flickering, flashing night sky

    › Produces 5,000 DVDs worth of data every day

    Every night, our sky beats with the pulses of radio light waves, most of which go unseen. A new array of radio antennas in California, called the Owens Valley Long Wavelength Array, is gearing up to catch some of this action, aiming to pick up signals from flaring stars, flashing planets and potentially even more exotic objects.

    The array has already produced a new video of the radio sky, showing how it flickers and morphs over 24 hours.

    “Our new telescope lets us see the entire sky all at once, and we can image everything instantaneously,” said Gregg Hallinan, an assistant professor of astronomy at the California Institute of Technology in Pasadena, and the principal investigator of the Owens Valley Long Wavelength Array.

    One of the key goals of the project is to monitor extrasolar space weather — the interaction between nearby stars and their orbiting planets. Our sun flares with radiation and hurtles particles and magnetic fields outward. Spectacular light displays, or auroras, are produced on the planets in our solar system when those particles interact with chemical elements in the planets’ atmospheres. The same is true for stars beyond our sun, and, if those stars have planets, they too would, in theory, have auroras.

    Measurements of these interactions in other star systems could reveal new information about the strength of planets’ magnetic fields — and thus their potential for harboring life. Magnetic fields were a critical factor in the development of life on Earth, offering protection from dangerous radiation and particles.

    The radio antennas, which combine to form a powerful radio telescope, are based at Caltech’s Owens Valley Radio Observatory, near Big Pine, California. Other partners include: NASA’s Jet Propulsion Laboratory, Pasadena, California; Harvard University, Cambridge, Massachusetts; the University of New Mexico, Albuquerque; Virginia Tech, Blacksburg; and the U.S. Naval Research Laboratory, headquartered in Washington.

    NASA JPL Owens Valley Low Frequency Radio Observatory
    JPL Caltech Owens Valley Low Frequency Radio Observatory

    The array’s station consists of 250 low-cost antennas, each about 3 feet (1 meter) in size, spread out in the Owens Valley. Future plans include thousands of additional antennas; the more antennas in the array, the greater the image sensitivity. The small size of the antennas has benefits as well, leading to a huge field of view in the same way that binoculars can see a large patch of sky. The array covers the entire viewable sky all at once.

    “Just as the antenna of your car radio can detect local radio stations no matter where they are around the car, these antennas can detect signals anywhere in the sky,” said Joseph Lazio, an astronomer on the project from JPL.

    The Owens Valley Long Wavelength Array might also be able to gather traces of radio light from the very first stars and galaxies.

    “The biggest challenge is that this weak radiation from the early universe is obscured by the radio emission from our own Milky Way galaxy, which is about a million times brighter than the signal itself, so you have to have very carefully calibrated data to see it,” said Hallinan. “That’s one of the primary goals of our collaboration — to try to get the first statistical measure of that weak signal from our cosmic dawn.”

    Lazio said the array will help in the design of future space missions. Some radio wavelengths are blocked or reflected off Earth’s atmosphere, but in space the whole radio spectrum can be observed.

    “Ultimately, we will likely need to construct a similar array of simple antennas and put it in space, or on the moon,” he said.

    One challenge of a project like this is managing the deluge of data. The array produces more than 5,000 DVDs worth of data every day. A supercomputer developed by a group led by Lincoln Greenhill of Harvard University for the National Science Foundation-funded Large-Aperture Experiment to Detect the Dark Ages delivers this torrent of data. It uses graphics processing units similar to those used in modern computer games to combine signals from all the antennas in real time. These combined signals are then sent to a second computer cluster, the All-Sky Transient Monitor, developed at Caltech and JPL, which produces all-sky images in real-time.

    The project is funded by Caltech, JPL, NASA and the National Science Foundation.

    A more detailed feature story about the project from Caltech is online at:

    http://www.caltech.edu/news/powerful-new-radio-telescope-array-searches-entire-sky-247-46754

    More information on the Long Wavelength Array is also online at:

    http://lwa.unm.edu

    See the full article here.

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    NASA JPL Campus

    Jet Propulsion Laboratory (JPL) is a federally funded research and development center and NASA field center located in the San Gabriel Valley area of Los Angeles County, California, United States. Although the facility has a Pasadena postal address, it is actually headquartered in the city of La Cañada Flintridge [1], on the northwest border of Pasadena. JPL is managed by the nearby California Institute of Technology (Caltech) for the National Aeronautics and Space Administration. The Laboratory’s primary function is the construction and operation of robotic planetary spacecraft, though it also conducts Earth-orbit and astronomy missions. It is also responsible for operating NASA’s Deep Space Network.

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  • richardmitnick 9:05 am on April 30, 2015 Permalink | Reply
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    From SKA: “World’s largest radio telescope has a permanent home for its headquarters” 

    SKA Square Kilometer Array

    SKA

    April 29, 2015
    William Garnier
    SKA Organisation Communications and Outreach Manager
    Email: w.garnier@skatelescope.org
    Mob.: +44 7814 908932

    At their meeting yesterday Wednesday 29 April, the Members of the Square Kilometre Array (SKA) Organisation decided that negotiations should start with the UK government to locate the permanent headquarters of the SKA project in the UK, at the University of Manchester’s Jodrell Bank site.

    Jodrell Bank houses the headquarters of the multinational SKA project for the current pre-construction phase. These premises will eventually be expanded to support the project as it transitions into the construction phase.

    “I am delighted that a permanent home for the SKA headquarters has been identified”, said Professor Philip Diamond, Director General of the SKA Organisation. “Clarity over the location of the headquarters is an important step for SKA, ahead of international negotiations to form an inter-governmental organisation and the beginning of construction in 2018.”

    The process for selecting the permanent headquarters began in 2014 when, following an agreed plan, Members were invited to submit bids. Two bids were received, from Italy and the United Kingdom, both of which were judged to be excellent and both suitable for the project’s needs. After thorough consideration, the Members of the SKA Organisation expressed their preference for the United Kingdom’s Jodrell Bank site as the future home for the SKA headquarters, thanks to the strong package offered by the UK government.

    The UK plan, backed by the UK government via the Science and Technology Facilities Council, the University of Manchester and Cheshire East Council, as well as Oxford and Cambridge Universities, envisages designing and constructing a unique campus for one of the most inspirational science projects of the 21st Century. The headquarters will be constructed to meet the needs of the SKA project and there is space to grow if the project requires it in the future.

    Members thanked the Italian government for submitting such a compelling bid, which demonstrates the very high profile the project has acquired in Italy. The SKA Director General and the SKA Board will work with Italian representatives to ensure that the high visibility and political support for the project in Italy can continue to maximise Italy’s engagement in the project.

    “Italy has been a key partner of the SKA since the early stages of the project”, said Professor Diamond. “I am confident they will maintain a high level of engagement on all fronts and I look forward to working with them as well as with all the other partner countries as we move into the next phase of the SKA.”

    See the full article here.

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    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.

     
  • richardmitnick 2:12 pm on April 29, 2015 Permalink | Reply
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    From ALMA: “Launch of ChiVO, the first Chilean Virtual Observatory” 

    ESO ALMA Array
    ALMA

    24 April 2015
    Valeria Foncea
    Education and Public Outreach Officer
    Joint ALMA Observatory
    Santiago, Chile
    Tel: +56 2 467 6258
    Cell: +56 9 75871963
    Email: vfoncea@alma.cl

    1

    After more than two years of work, today was launched the first Chilean Virtual Observatory (ChiVO), an astro-informatic platform for the administration and analysis of massive data coming from the observatories built across the country. Its implementation will provide advanced computing tools and research algorithms to the Chilean astronomical community.

    3
    The project designed to manage and analyze the almost 250 terabytes of data that the Atacama Millimeter/submillimeter Array (ALMA) will generate each year has joined the International Virtual Observatory Alliance, becoming a key initiative in Chile’s contribution to astroinformatics around the world.

    4

    “This project is a major contribution for Chilean astronomers -said Diego Mardones, an astronomer at Universidad de Chile- because besides being an excellent tool for exploring the huge quantity of astronomical data that will be generated in our country in the coming years, it opens new opportunities of interdisciplinary research.”

    2
    ChiVO main team. Left to right: Paulina Troncoso, Astronomer; Ricardo Contreras, U. of Concepción; Jorge Ibsen, ALMA; Mauricio Solar, ChiVO’s director, U. Técnica Federico Santa María (UFSM); Paola Arellano, REUNA; Victor Parada, U. of Santiago; Marcelo Mendoza, ChiVO’s alternate director, UFSM; Diego Mardones, U. of Chile; Mauricio Araya, UFSM; María; Guillermo Cabrera, U. of Chile.

    The project led by Universidad Técnica Federico Santa María (UTFSM) is a successful collaboration with four other universities in Chile (Universidad de Chile, Universidad Católica, Universidad de Concepción y Universidad de Santiago) and was funded by FONDEF, the Chilean Scientific and Technological Development Fund. Furthermore, both the Atacama Large Millimeter/submillimeter Array (ALMA) and REUNA, the National Universities Network, are associated to the project. Thanks to ChiVO, Chile will become a member of the International Virtual Observatories Alliance (IVOA) and it will be accessible for all astronomers making their research in the country through its website http://www.chivo.cl.

    For the project’s director, Mauricio Solar, “this innovation will allow astronomical data to be processed in Chile using high-quality, local human capital and integrating Chilean astro-informatics with the international community at the highest levels of development.”

    With new telescopes being constructed in Chile, the amount of astronomical data generated will only increase. As an example, once ALMA is operating at full capacity, it will produce close to 250 terabytes of data each year. ChiVO will enable Chilean astronomers to access this data with high transfer rates, provide the infrastructure for high storage capacity and access the analysis of the data.

    “ChiVO and the services provided by it will be a key tool for the Chilean astronomical community, added Jorge Ibsen, director of ALMA’s Department of Computing. “ALMA is proud to be part of this project that will boost the usage of the astronomical data generated in the country.

    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 12:37 pm on April 28, 2015 Permalink | Reply
    Tags: Amazon Web Services AstroCompute, , , Radio Astronomy,   

    From SKA: “Seeing stars through the Cloud” 

    SKA Square Kilometer Array

    SKA

    SKA & Amazon Web Services team up to offer AstroCompute in the Cloud grant

    Square Kilometre Array (SKA) Organisation is teaming up with Amazon Web Services (AWS) to use innovative cloud computing solutions to explore ever-increasing amounts of astronomy data in ways that were previously unimaginable. Located in Australia and Africa, the SKA will be the world’s largest radio telescope and is often considered to be the largest public science Big Data project, set to ultimately produce massive amounts of data – several times the global Internet traffic.

    28 April, 2015
    William Garnier
    SKA Organisation Communications and Outreach Manager
    w.garnier@skatelescope.org
    +44 7814 908932

    Today, SKA Organisation and AWS are launching the AstroCompute in the Cloud grant programme to accelerate the development of innovative tools and techniques for processing, storing and analysing the global astronomy community’s vast amounts of astronomic data in the cloud. Grant recipients will have access to credits for AWS cloud services over a two-year period and up to one petabyte (PB) of storage for data contributed by SKA partners, which AWS will make available as a public dataset. Anyone associated with or using radio astronomical telescopes or radio astronomical data resources around the world is welcome to apply.

    “With the SKA, we will be generating more data than the entire Internet traffic at any single time,” said Tim Cornwell, the SKA Organisation Architect and administrator of the grant. “So we’re looking into innovative cloud solutions to help us cope with never-before-seen volumes of data, using techniques that are yet to be invented.”

    “This is an exciting opportunity, not only for our partner institutions, but for all companies and research facilities around the world dealing with astronomy data,” said Professor Philip Diamond, SKA Organisation Director-General. “The call is to help us explore how cloud computing can help process the data deluge we are expecting in astronomy in the 21st century – and in particular with the SKA.”

    In its first phase of construction, SKA will include two game-changing telescopes, one consisting of more than one hundred thousand low frequency antennas, and one with about two hundred large dishes. Supercomputers will translate the enormous volume of raw data coming from the telescopes into a useable form for astronomers. With observations expected to run full-time, data will flow continuously and supercomputers will process it on the fly, transmitting useful data to an archive and deleting contaminated or otherwise unnecessary data in real time. To handle the data, and develop the know-how to process it, new smart algorithms and software will be required.

    “Through our Scientific Computing program, our grants and our public datasets, we’ve found that when researchers have access to the tools and data they need, they find innovative ways of solving big data challenges,” said Jamie Kinney, senior manager for scientific computing, Amazon Web Services, Inc. “The SKA is an ambitious project which presents an unprecedented opportunity to leverage a tremendous amount of data to explore the Universe.”

    Beyond the field of astronomy the development of cloud processing and data analysis and visualisation tools is certain to have major applications in everyday life. Supercomputing is increasingly used by pharmaceutical companies to design better drugs, by weather forecasting to refine predictions up to a week in advance, and by engineers to design smarter infrastructure.

    “There’s an increasingly strong link between fundamental research and computing, with all the potential spinoffs benefitting society that come with it,” said Tim Cornwell. “CERN, the European Organisation for Nuclear Research, realised very early they would face a challenge to distribute the amount of data from their experiments to physicists around the world. To solve it, they created the World Wide Web. SKA is the next step.”

    Statements from SKA partners

    Peter Quinn, Executive Director of the International Centre for Radio Astronomy Research (ICRAR), Perth, Australia: “We’re pleased to see Amazon Web Services support the Square Kilometre Array project. ICRAR has been actively using AWS for several years to prototype data and processing systems for the SKA and to demonstrate the benefits of cloud technologies for radio astronomy. This is a great example of how the SKA and industry are working together to innovate in areas that will not only help science but also generate down-to-earth benefits for the global community.”

    Lewis Ball, Director of CSIRO Astronomy and Space Science, Marsfield, Australia: “The management of big data is now a challenge faced by researchers worldwide. For example, once fully operational, our ASKAP telescope (one of the SKA precursor telescopes) will generate about five petabytes of data per year. Big computing resources will support this vital scientific research, expand capabilities and enable exciting new discoveries – not only for astronomy but also other data-intensive investigations right across the scientific spectrum.”

    Justin Jonas, Associate Director at SKA South Africa: “The computing needs of the SKA and its pathfinder and precursor facilities present some problems that are unique to radio astronomy, but others are common with other Big Data and High Performance Computing applications. One of our current challenges is to identify the most appropriate compute platforms for these two classes of applications. Cloud computing is an attractive option that is already being used to good effect by MeerKAT (one of the SKA precursor telescopes) scientists, engineers and software developers. The AWS grant will allow us to fully explore the capabilities of cloud computing in the context of MeerKAT and SKA data processing and delivery. We foresee that students in our Human Capital Development Programme will also benefit from this grant, giving them first-hand experience in this cutting edge computing environment.”

    Mike Garrett, ASTRON Director, the Netherlands: “It makes sense for a globally distributed project like the SKA to be an early adopter of cloud technology. The cloud will impact every possible aspect of the project, from telescope maintenance and operations, to collaborative data sharing and the nature and process of scientific discovery itself.”

    Brian Glendenning, Head of the Data Management and Software Department at the NRAO: “The National Radio Astronomy Observatory (NRAO) is pleased that grants are available to all radio astronomy users, including users with NRAO data. NRAO has recently started a pilot project to configure and implement a supported instance of its radio interferometric data reduction software package (CASA) on AWS. NRAO will be able to assist (e.g., via providing supported CASA virtual machines with tuned parallelization parameters) the radio community as it makes the transition to this era of on-demand computing.”

    See the full article here.

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    About SKA

    SKA Pathfinder Radio Telescope
    SKA ASKAP Pathfinder

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    SKA Murchison Wide Field Array

    SKA Meerkat telescope
    SKA Meerkat Radio Telescope

    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.

     
  • richardmitnick 11:24 am on April 21, 2015 Permalink | Reply
    Tags: , , Event Horizon Telescope, , Radio Astronomy,   

    From U Arizona: “Virtual Telescope Expands to See Black Holes” 

    U Arizona bloc

    University of Arizona

    April 21, 2015
    Daniel Stolte

    1
    The 10-meter South Pole Telescope, at the National Science Foundation’s Amundsen-Scott South Pole Station, joined the global Event Horizon Telescope array in January. (Photo: Dan Marrone/UA)

    A team led by the UA has added Antarctica’s largest astronomical telescope to the Event Horizon Telescope — a virtual telescope as big as planet Earth — bringing the international EHT collaboration closer to taking detailed images of the very edge, or “event horizon,” of the supermassive black hole at the center of the Milky Way galaxy.

    2
    The South Pole Telescope and the Atacama Pathfinder Experiment joined together in a “Very Long Baseline Interferometry” experiment for the first time in January. The two telescopes simultaneously observed two sources — the black hole at the center of the Milky Way galaxy, Sagittarius A*, and the black hole at the center of the distant galaxy Centaurus A — and combined their signals to synthesize a telescope 5,000 miles across. (Image: Dan Marrone/UA)

    Astronomers building an Earth-size virtual telescope capable of photographing the event horizon of the black hole at the center of our Milky Way have extended their instrument to the bottom of the Earth — the South Pole — thanks to recent efforts by a team led by Dan Marrone of the University of Arizona.

    Marrone, an assistant professor in the UA’s Department of Astronomy and Steward Observatory, and several colleagues flew to the National Science Foundation’s Amundsen-Scott South Pole Station in December to bring the South Pole Telescope, or SPT, into the largest virtual telescope ever built — the Event Horizon Telescope, or EHT. By combining telescopes across the Earth, the EHT will take the first detailed pictures of black holes.

    The EHT is an array of radio telescopes connected using a technique known as Very Long Baseline Interferometry, or VLBI. Larger telescopes can make sharper observations, and interferometry allows multiple telescopes to act like a single telescope as large as the separation — or “baseline” — between them.

    ESO APEX
    The Atacama Pathfinder Experiment telescope sits atop the plateau of Chajnantor in the Chilean Andes, more than 16,000 feet high. The plane of our galaxy — the Milky Way — can be seen in the sky looking like a band of faint, glowing clouds. To the left of APEX is the central region of the Milky Way, where a supermassive black hole lurks at the core of our galaxy. (Photo: ESO/B. Tafreshi/TWAN/twanight.org)

    “Now that we’ve done VLBI with the SPT, the Event Horizon Telescope really does span the whole Earth, from the Submillimeter Telescope on Mount Graham in Arizona, to California, Hawaii, Chile, Mexico, Spain and the South Pole,” Marrone said. “The baselines to SPT give us two to three times more resolution than our past arrays, which is absolutely crucial to the goals of the EHT. To verify the existence of an event horizon, the ‘edge’ of a black hole, and more generally to test [Albert] Einstein’s theory of general relativity, we need a very detailed picture of a black hole. With the full EHT, we should be able to do this.”

    The prime EHT target is the Milky Way’s black hole, known as Sagittarius A* (pronounced “A-star”).

    4
    Sagittarius A*

    Even though it is 4 million times more massive than the sun, it is tiny to the eyes of astronomers. Because it is smaller than Mercury’s orbit around the sun, yet almost 26,000 light-years away, studying its event horizon in detail is equivalent to standing in California and reading the date on a penny in New York.

    With its unprecedented resolution, more than 1,000 times better than the Hubble Space Telescope, the EHT will see swirling gas on its final plunge over the event horizon, never to regain contact with the rest of the universe.

    NASA Hubble Telescope
    NASA/ESA Hubble

    If the theory of general relativity is correct, the black hole itself will be invisible because not even light can escape its immense gravity.

    First postulated by Albert Einstein’s general theory of relativity, the existence of black holes has since been supported by decades’ worth of astronomical observations. Most if not all galaxies are now believed to harbor a supermassive black hole at their center, and smaller ones formed from dying stars should be scattered among their stars. The Milky Way is known to be home to about 25 smallish black holes ranging from five to 10 times the sun’s mass. But never has it been possible to directly observe and image one of these cosmic oddities.

    Weighing 280 tons and standing 75 feet tall, the SPT sits at an elevation of 9,300 feet on the polar plateau at Amundsen-Scott, which is located at the geographic South Pole. The University of Chicago built SPT with funding and logistical support from the NSF’s Division of Polar Programs. The division manages the U.S. Antarctic Program, which coordinates all U.S. research on the southernmost continent.

    The 10-meter SPT operates at millimeter wavelengths to make high-resolution images of cosmic microwave background radiation, the light left over from the Big Bang. Because of its location at the Earth’s axis and at high elevation where the polar air is largely free of water vapor, it can conduct long-term observations to explore some of the biggest questions in cosmology, such as the nature of dark energy and the process of inflation that is believed to have stretched the universe exponentially in a tiny fraction of the first second after the Big Bang.

    “We are thrilled that the SPT is part of the EHT,” said John Carlstrom, who leads the SPT collaboration. “The science, which addresses fundamental questions of space and time, is as exciting to us as peering back to the beginning of the universe.”

    To incorporate the SPT into the EHT, Marrone’s team constructed a special, single-pixel camera that can sense the microwaves hitting the telescope. The Academia Sinica Institute for Astronomy and Astrophysics in Taiwan provided the atomic clock needed to precisely track the arrival time of the light. Comparing recordings made at telescopes all over the world allows the astronomers to synthesize the immense telescope. The Smithsonian Astrophysical Observatory and Haystack Observatory of the Massachusetts Institute of Technology provided equipment to record the microwaves at incredibly high speeds, generating nearly 200 terabytes per day.

    “To extend the EHT to the South Pole required improving our data capture systems to record data much more quickly than ever before,” said Laura Vertatschitsch of the Smithsonian Astrophysical Observatory. A new “digital back end,” developed by Vertatschitsch and colleagues, can process data four times faster than its predecessor, which doubles the sensitivity of each telescope.

    For their preliminary observations, Marrone’s team trained its instrument on two known black holes, Sagittarius A* in our galaxy, and another, located 10 million light-years away in a galaxy named Centaurus A.

    5
    Centaurus A
    Colour composite image of Centaurus A, revealing the lobes and jets emanating from the active galaxy’s central black hole. This is a composite of images obtained with three instruments, operating at very different wavelengths. The 870-micron submillimetre data, from LABOCA on APEX, are shown in orange. X-ray data from the Chandra X-ray Observatory are shown in blue. Visible light data from the Wide Field Imager (WFI) on the MPG/ESO 2.2 m telescope located at La Silla, Chile, show the background stars and the galaxy’s characteristic dust lane in close to “true colour”.

    NASA Chandra Telescope
    NASA/Chandra

    ESO 2.2 meter telescope
    MPG/ESO 2.2 m telescope

    For this experiment, the SPT and the Atacama Pathfinder Experiment, or APEX, telescope in Chile observed together, despite being nearly 5,000 miles apart. These data constitute the highest- resolution observations ever made of Centaurus A (though the information from a single pair of telescopes cannot easily be converted to a picture).

    “VLBI is very technically challenging, and a whole system of components had to work perfectly at both SPT and APEX for us to detect our targets,” said Junhan Kim, a doctoral student at the UA who helped build and install the SPT EHT receiver. “Now that we know how to incorporate SPT, I cannot wait to see what we can learn from a telescope 10,000 miles across.”

    The next step will be to include the SPT in the annual EHT experiments that combine telescopes all over the world. Several new telescopes are prepared to join the EHT in the next year, meaning that the next experiment will be the largest both geographically and with regard to the number of telescopes involved. The expansion of the array is supported by the National Science Foundation Division of Astronomical Sciences through its new Mid-Scale Innovations Program, or MSIP.

    Shep Doeleman, who leads the EHT and the MSIP award, noted that “the supermassive black hole at the Milky Way’s center is always visible from the South Pole, so adding that station to the EHT is a major leap toward bringing an event horizon into focus.”

    This work was funded through NSF grants AST-1207752 to Marrone; AST-1207704 to Doeleman at MIT’s Haystack Observatory; and AST-1207730 to Carlstrom at the University of Chicago.

    An international research collaboration led by the University of Chicago manages the SPT. The NSF-funded Physics Frontier Center of the Kavli Institute for Cosmological Physics, the Kavli Foundation, and the Gordon and Betty Moore Foundation provide partial support.

    The APEX telescope, located in Chile’s Atacama Desert, is a collaboration of the European Southern Observatory, the Max Planck Institute for Radioastronomy and the Onsala Space Observatory in Sweden.

    See the full article here.

    Collaborators in the EHT

    ALMA
    ASIAA
    Arizona Radio Observatory (U. of Arizona)
    Caltech Submillimeter Observatory
    CARMA
    ESO
    Harvard Smithsonian Center for Astrophysics
    Submillimeter Array
    University of Massachusetts – Amherst
    IRAM
    MIT Haystack Observatory
    MPIfR
    NAOJ
    NRAO
    NSF – The EHT project gratefully acknowledges support from the National Science Foundation
    Onsala Space Observatory
    Universidad de Concepción
    University of California – Berkeley (RAL)
    University of Chicago (South Pole Telescope)

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

    U Arizona campus

    The University of Arizona (UA) is a place without limits-where teaching, research, service and innovation merge to improve lives in Arizona and beyond. We aren’t afraid to ask big questions, and find even better answers.

    In 1885, establishing Arizona’s first university in the middle of the Sonoran Desert was a bold move. But our founders were fearless, and we have never lost that spirit. To this day, we’re revolutionizing the fields of space sciences, optics, biosciences, medicine, arts and humanities, business, technology transfer and many others. Since it was founded, the UA has grown to cover more than 380 acres in central Tucson, a rich breeding ground for discovery.

    Where else in the world can you find an astronomical observatory mirror lab under a football stadium? An entire ecosystem under a glass dome? Visit our campus, just once, and you’ll quickly understand why the UA is a university unlike any other.

     
  • richardmitnick 9:29 am on April 13, 2015 Permalink | Reply
    Tags: , , Radio Astronomy,   

    From SKA via ZDNET: “The computers that will help scientists step closer to the Big Bang” 

    SKA Square Kilometer Array

    SKA

    q
    ZDNET

    March 20, 2015
    Nick Heath

    In the course of a day the Square Kilometre Array (SKA) is expected to gather more data than passes across the internet.

    The SKA will be an array of 3,000 radio telescopes that will gather cosmic emissions in an attempt to see the universe a few hundred of million years after the Big Bang – farther back in time than any telescope has glimpsed.

    Handling the 14 exabytes of data that will be gathered by the dishes in South Africa and Australia will require processing power equal to several million of today’s fastest computers.

    A high-performance computing architecture with data transfer links that far exceed current state-of-the-art technology must be developed to gather, store and analyse the 13 billion year old data.

    To meet this computing challenge IBM and its partners at ASTRON, the Netherlands Institute for Radio Astronomy, are coming up with some novel machines, including what they claim is the world’s first water-cooled, 64-bit microserver.

    The prototype microserver, on show at the CeBIT technology fair in Hannover in Germany, is roughly the size of a smartphone, between four and 10 times smaller than traditional rack mounted servers.

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    3

    The researchers are planning to pack 128 of the microserver boards, using the newest T4240 chips, into a 2U rack unit with 1536 cores and 3072 threads, with up to 6TB of DRAM.

    The microservers have been developed under a €35.9m project called Dome, which is run by IBM and Astron to try to solve the exascale computing challenges posed by the SKA.

    When it goes live in 2024, the SKA will be the world’s most sensitive radio telescope, collecting a deluge of radio signals from deep space and storing one petabyte of data each day.

    “With the SKA we will be able to fill big gaps in our knowledge of the universe,” says Albert-Jan Boonstra, the scientific director of ASTRON.”We’ll be able to map the so-called ‘dark ages,’ the epoch of reionization, when the stars and galaxies formed.”

    See the full article here.

    Please help promote STEM in your local schools.
    STEM Icon

    Stem Education Coalition

    SKA Banner

    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.

     
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