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  • richardmitnick 3:15 pm on May 17, 2016 Permalink | Reply
    Tags: , , , HR 8799, , Radio Astronomy   

    From ALMA: “Cometary Belt around Distant Multi-Planet System Hints at Hidden or Wandering Planets” 

    ESO/NRAO/NAOJ ALMA Array
    ESO/NRAO/NAOJ ALMA Array

    ALMA

    17 May 2016
    Valeria Foncea

    Education and Public Outreach Officer

    Joint ALMA Observatory

    Santiago, Chile

    Tel: +56 2 467 6258

    Cell: +56 9 75871963
    Email: valeria.foncea@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
    ALMA image of dusty cometary ring around HR 8799, the only star where multiple planets have been imaged. The new data suggest the planets either migrated or another undiscovered planet is present. The zoom-in portion of the image, taken with ESO’s Very Large Telescope, shows the location of the known planets in this system in relation to a graphical representation of the central star. Credit: Booth et al., ALMA (NRAO/ESO/NAOJ); A. Zurlo, et al
    ___________________________________________________________

    Astronomers using the Atacama Large Millimeter/submillimeter Array (ALMA) have made the first high-resolution image of the cometary belt (a region analogous to our own Kuiper belt) around HR 8799, the only star where multiple planets have been imaged directly.

    Kuiper Belt. Minor Planet Center
    Kuiper Belt. Minor Planet Center

    The shape of this dusty disk, particularly its inner edge, is surprisingly inconsistent with the orbits of the planets, suggesting that either they changed position over time or there is at least one more planet in the system yet to be discovered.

    “This data really allow us to see the inner edge of this disk for the first time,” explains Mark Booth from Pontificia Universidad Católica de Chile and lead author of the study. “By studying the interactions between the planets and the disk, this new observation shows that either the planets that we see have had different orbits in the past or there is at least one more planet in the system that is too small to have been detected.”

    The disk, which fills a region 150 to 420 times the Sun-Earth distance, is produced by the ongoing collisions of cometary bodies in the outer reaches of this star system. ALMA was able to image the emission from millimeter-size debris in the disk; according to the researchers, the small size of these dust grains suggests that the planets in the system are larger than Jupiter. Previous observations with other telescopes at shorter wavelengths did not detect this discrepancy in the disk. It is not clear if this difference is due to the low resolution of the previous observations or because different wavelengths are sensitive to different grain sizes, which would be distributed slightly differently.

    HR 8799 is a young star approximately 1.5 times the mass of the Sun located 129 light-years from Earth in the direction of the constellation Pegasus.

    “This is the very first time that a multi-planet system with orbiting dust is imaged, allowing for direct comparison with the formation and dynamics of our own Solar System,” explains Antonio Hales, co-author of the study from the National Radio Astronomy Observatory in Charlottesville, Virginia.

    Additional information

    These results were published in the Monthly Notices of the Royal Astronomical Society titled Resolving the Planetesimal Belt of HR 8799 with ALMA by Booth et al., May 2016.
    Preprint: http://arxiv.org/abs/1603.04853

    The research team was composed by Mark Booth ([1], [2]), Andrés Jordán ([1], [3]), Simón Casassus ([2], [4]), Antonio S. Hales ([5], [6]), William R. F. Dent ([5]), Virginie Faramaz ([1]), Luca Matrà ([7], [8]), Denis Barkats ([9]), Rafael Brahm ([1], [3]) Jorge Cuadra ([1], [2]).

    [1] Instituto de Astrofísica, Pontificia Universidad Católica de Chile, Vicuña Mackenna 4860, Santiago, Chile
    [2] Millennium Nucleus “Protoplanetary Disks”
    [3] Millennium Institute of Astrophysics, Vicuña Mackenna 4860, Santiago, Chile
    [4] Departamento de Astronomía, Universidad de Chile, Casilla 36-D, Santiago, Chile
    [5] Joint ALMA Observatory, Alonso de Córdova 3107, Vitacura 763-0355, Santiago, Chile
    [6] National Radio Astronomy Observatory, 520 Edgemont Road, Charlottesville, Virginia, 22903-2475, USA
    [7] Institute of Astronomy, University of Cambridge, Madingley Road, Cambridge CB3 0HA, UK
    [8] European Southern Observatory, Alonso de Córdova 3107, Vitacura, Casilla 19001, Santiago, Chile
    [9] Harvard University, 60 Garden Street, Cambridge, MA 02138, USA

    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.

    NRAO Small

    ESO 50

    NAOJ

     
  • richardmitnick 11:36 am on May 16, 2016 Permalink | Reply
    Tags: , , , , Radio Astronomy,   

    From NOVA: “Revealing the Universe’s Mysterious Dark Age” 

    PBS NOVA

    NOVA

    06 Apr 2016 [They just put this in social media]
    Marcus Woo

    The universe wasn’t always like this. Today it’s filled with glittering galaxies, scattered across space like city lights seen from above. But there was a time when all was dark. Really dark.

    Dark Ages Universe ESO
    Dark Ages Universe ESO

    1
    A time-lapse visualization of what the cosmic web’s emergence might have looked like. No image credit

    First, a very brief history of time: from the Big Bang, the universe burst onto the scene as a tiny but glowing inferno of energy. Immediately, it expanded and cooled, dimming into darkness as particles condensed out of the hot soup like droplets of morning dew. Electrons and protons coalesced into atoms, which formed stars, galaxies, planets, and eventually us.

    Inflationary Universe. NASA/WMAP
    Inflationary Universe. NASA/WMAP

    Universe map Sloan Digital Sky Survey (SDSS) 2dF Galaxy Redshift Survey
    Universe map Sloan Digital Sky Survey (SDSS) 2dF Galaxy Redshift Survey

    But a crucial piece still eludes scientists. It’s a gap of several hundred million years that was filled with darkness—a darkness both literal and metaphorical. Astronomers call this period the dark ages, a time that’s not just bereft of illumination, but also devoid of data.

    The Big Bang left a glowing imprint on the entire sky called the cosmic microwave background,,,

    Cosmic Microwave Background per ESA/Planck
    Cosmic Microwave Background per ESA/Planck

    ESA/Planck
    ESA/Planck
    ,,,representing the universe when it was 380,000 years old. Increasingly precise measurements of this radiation have revealed unprecedented details about the earliest cosmic moments. But from then until the emergence of galaxies big and bright enough for today’s telescopes, scientists don’t have any information. Ever mysterious, these dark ages are the final frontier of cosmology.

    And it’s a fundamental frontier. It represents the universe’s most formative years, when it matured from a primordial soup to the cosmos we recognize today.

    Even without much direct data about this era, researchers have made great strides with theory and computer models, simulating the universe through the birth of the first stars. Soon, they may be able to put those theories to the test. In a few years, a suite of new telescopes with new capabilities will start peering into the darkness, and for the first time, astronomers will reach into the unknown.

    The Final Frontier

    Considering that it’s the entire universe they’re trying to understand, cosmologists have done a pretty good job. Increasingly powerful telescopes have allowed them to peer to greater distances, and because the light takes so long to reach the telescopes, astronomers can see farther back in time, capturing snapshots of a universe only a few hundred million years old, just as it emerged from the dark ages. Given that the universe is now 13.7 billion years old, that’s like taking a picture of the cosmos as a toddler.

    That makes the cosmic microwave background, or CMB, clike a detailed ultrasound. This radiation contains the first photons that escaped the yoke of the universe’s primordial plasma. When the universe was a sea of radiation and particles, photons couldn’t travel freely because they kept running into electrons. But about 380,000 years after the Big Bang, the universe had cooled enough that protons were able to lasso electrons into an orbit to form hydrogen atoms. Without electrons in their way, the newly liberated photons could now fly through the cosmos and, more than 13 billion years later, enter the detectors of instruments like the Planck satellite, giving cosmologists the earliest picture of the universe.

    But from this point on, until the universe was a few hundred million years old—the limit of today’s telescopes—astronomers have nothing. It’s as if they have a photo album documenting a person’s entire life, with pictures of young adulthood, adolescence, childhood, and even before birth, but nothing from when the person learned to talk or walk—years of drastic changes.

    That doesn’t mean astronomers have no clue about this period. “People have thought about the first stars since the 1950s,” says Volker Bromm, a professor of astronomy at the University of Texas, Austin. “But they were very speculative because we did not know enough cosmology.” Not until the 1980s did researchers develop more accurate theories that incorporated dark matter, the still-unknown type of particle or particles that comprises about 85% of the matter in the universe. But the first key breakthrough came in 1993, when NASA’s COBE satellite measured the CMB for the first time, collecting basic but crucial data about what the universe was like at the very beginning—the so-called initial conditions of the cosmos. Theorists such as Martin Rees, now the Astronomer Royal of the United Kingdom, and Avi Loeb, a professor of astrophysics at Harvard, realized you could plug these numbers into the equations that govern how the first gas clouds and stars could form. “You could feed them into a computer simulation,” Loeb says. “It’s a well-defined problem.”

    Both Rees and Loeb would influence Bromm, then a graduate student at Yale. Rees and his early work in the 1980s, in particular, inspired Tom Abel, who was a visiting scientist during the 1990s at the University of Illinois, Urbana-Champaign. Independently, Abel and Bromm would make some of the first computer models of their kind to simulate the first stars. “That really opened the field,” Loeb says. “When I started, there were maybe one or a few people even willing to discuss this subject.”

    Theorists like Bromm and Abel, now a professor at Stanford, have since pieced together a blow-by-blow account of the dark ages. Here’s how they think it all went down.

    Then There Was Light

    In the earliest days, during the time that we see in the CMB, the entire universe was bright and as hot as the surface of the sun. But the universe kept expanding and cooling, and after nearly 15 million years, it was as cool as room temperature. “In principle, if there were planets back then, you could’ve had life on them if they had liquid water on their surface,” Loeb says. The temperature continued to fall, and the infrared radiation that suffused the universe lengthened, shifting to radio waves. “Once you cool even further, the universe became a very dark place,” Loeb says. The dark ages had officially begun.

    Meanwhile, the simulations show, things began to stir. The universe was bumpy, with regions of slightly higher and lower densities, which grew from the random quantum fluctuations that emerged in the Big Bang. These denser regions coaxed dark matter to start clumping together, forming a network of sheets and filaments that crisscrossed the universe. At the intersections, denser globs of dark matter formed. Once these roundish halos grew to about 10,000 times the mass of the Sun, Abel says—a few tens of millions of years after the Big Bang—they had enough gravity to corral hydrogen atoms into the first gas clouds.

    Those clouds could then accumulate more gas, heating up to hundreds of degrees. The heat generated enough pressure to prevent further contraction. Soon, the clouds settled into enormous, but rather dull, balls of gas about 100 light years in diameter, Abel says.

    But if the dark matter halos reached masses 100,000 times that of the sun, they could accrue enough gas that the clouds could heat up to about 1000 degrees—and that’s when things got interesting. The surplus energy allowed hydrogen atoms to merge two at a time and form hydrogen molecules—picture two balls attached with a spring. When two hydrogen molecules collide, they vibrate and emit photons that carry away energy.

    When that happens, the molecules are converting the vibrating energy that is heat into radiation that’s lost into space. These interactions cooled the gas, slowing down the molecules and allowing the clouds to collapse. As the clouds grew denser, their temperatures and pressures soared, igniting nuclear fusion. That’s how the first stars were born.

    These first stars, which formed by the time the universe was a couple hundred million years old, were much bigger than those in today’s universe. By the early 2000s, Abel’s simulations, which he says are the most realistic and advanced yet, showed that the first stars weighed about 30 to 300 times the mass of the sun. Using different techniques and algorithms, Bromm says he arrived at a similar answer. For the first time, researchers had a good idea as to what the first objects in the universe were like.

    Massive stars consume fuel like gas-guzzling SUVs. They live fast and die young, collapsing into supernovae after only a few million years.

    Supernova remnant Crab nebula. NASA/ESA Hubble
    Supernova remnant Crab nebula. NASA/ESA Hubble

    NASA/ESA Hubble Telescope
    NASA/ESA Hubble Telescope

    In cosmic timescales, that’s the blink of an eye. “You really want to think of fireworks at these early times,” Abel says. “Just flashing everywhere.”

    In general, the first stars were sparse, separated by thousands of light years. Over the next couple hundred million years, though, guided by the clustering of dark matter, the stars started grouping together to form baby galaxies. During this cosmic dawn, as astronomers call it, galaxies merged with one another and became bigger galaxies. Only after billions and billions of years would they grow into those like our own Milky Way, with hundreds of billions of stars.

    Lifting the Fog

    But there’s more to the story. The first stars shone in many wavelengths, and especially strongly in ultraviolet. The universe’s expansion would’ve stretched this light to visible and infrared wavelengths, which many of our best telescopes are designed to detect. Problem is, during the time of the first stars, a thick fog of neutral hydrogen gas blanketed the whole universe. This gas absorbed shorter-wavelength ultraviolet light, obscuring the view from telescopes. Fortunately, though, this fog would soon lift.

    “This state of affairs can’t last for very long,” says Richard Ellis, an astronomer at the European Southern Observatory in Germany.

    ESO 50 Large
    ESO

    “These ultraviolet photons have sufficient energy to break apart the hydrogen atom back into an electron and a proton.” The hydrogen was ionized, turning into a lone proton that could no longer absorb ultraviolet. The gas was now transparent.

    During this so-called period of reionization, galaxies continued to grow, producing more ultraviolet light that ionized the hydrogen surrounding them, clearing out holes in the fog. “You can imagine the hydrogen like Swiss cheese,” Loeb says. Those bubbles grew, and by the time the universe was around 800 million years old, the ultraviolet radiation ionized the hydrogen between the galaxies, leaving the entire cosmos clear and open to the gaze of telescopes. The dark ages were over, revealing a universe that looked more or less like it does today.

    Seeing into the Dark

    Of course, many details have to be worked out. Astronomers like Ellis are focusing on the latter stages of the dark ages, using the most powerful telescopes to extract clues about this reionization epoch.

    One big question has been whether the ultraviolet light from early galaxies was enough to ionize the whole universe. If it wasn’t, astronomers would have to find another exotic source—like black holes that blast powerful, ionizing jets of radiation—that would have finished the job.

    To find the answer, Ellis and a team of astronomers stretched the Hubble Space Telescope to its limits, extracting as much light as possible from one small patch of sky. These observations reached some of the most distant corners of the universe, discovering some of the earliest galaxies ever seen, during the heart of this reionization era. Their observations suggested that galaxies—large populations of small galaxies, in particular—did seem to have enough ultraviolet light to ionize the universe. Maybe nothing exotic is needed.

    NASA/ESA  Hubble Deep Field
    NASA/ESA Hubble Deep Field

    But to know exactly how it happened, astronomers need new telescopes, like the James Webb Space Telescope set for launch in 2018.

    NASA/ESA/CSA Webb Telescope annotated
    “NASA/ESA/CSA Webb Telescope annotated

    “With the current facilities, it’s just an imponderable,” Ellis says. “We don’t have the power to study these galaxies in any detail.”

    Other astronomers are focusing not on the galaxies, but the hydrogen fog itself. It turns out that the spins of a hydrogen atom’s proton and electron can flip-flop in direction. When the spins go from being aligned to unaligned, the atom releases radiation at a wavelength of 21 centimeters, or 8.27 inches, a telltale signal of neutral hydrogen that astronomers call the 21-cm line. The expanding universe would have stretched this signal to the point where it became a collection of radio waves. The more distant the source of light, the more the radiation gets stretched. By using arrays of radio telescopes to measure the extent of this stretching, astronomers can map the distribution of hydrogen at different points in time. They could then track how those holes in the gas grew and grew until the gas was all ionized.

    “It’s surveying the volume of the universe on a scale that you can’t imagine doing in any way other than through this method—it’s really quite incredible,” says Aaron Parsons, an astronomer at the University of California, Berkeley, who’s leading a project called HERA, which will consist of 352 radio antennae in South Africa.

    HERA NSF
    NSF HERA, South Africa

    Once online, the telescope could give an unprecedented view of reionization. “You can almost imagine making a movie of how the first stars galaxies formed, how they interacted, heated up, ionized, and turned into the galaxies we recognize today.”

    Other telescopes like LOFAR in the Netherlands and the Murchison Widefield Array in Australia will make similar measurements.

    ASTRON LOFAR Map
    ASTRON LOFAR Map

    ASTRON LOFAR Radio Antenna Bank
    ASTRON LOFAR Radio Antenna Bank

    SKA Murchison Widefield Array
    SKA Murchison Widefield Array

    But HERA will be more sensitive, Parsons says. And already with 19 working antennae in place, it might be closest to success, adds Loeb, who isn’t part of the HERA team. “Within a couple years, we should have the first detection of the 21-cm line from this epoch of reionization, which would be fantastic because it would allow us to see the environmental effect of ultraviolet radiation from the first stars and first galaxies on the rest of the universe.”

    This kind of data is crucial for informing computer models like the kind that Abel and Bromm have developed. But despite their successes, theorists are at the point where they need data to test whether their models are accurate.

    Unfortunately, that data won’t be pictures of the first stars. Even the most powerful telescopes won’t be able to see the brightest of them. The first galaxies contain only a few hundred stars and are just too small and faint. “We’ll come ever closer,” Abel says. “It’s very difficult to imagine we’ll actually see those in the near future, but we’ll see their brighter cousins.”

    In fact, the darkest of times, during the couple hundred million years between the CMB and the appearance of the first stars, may always remain beyond astronomers’ grasp. “We currently don’t have any idea of how you could get any direct information about that period,” he says.

    Still, new telescopes over the next few decades promise to reveal much of the dark ages and whether the story theorists are telling is true or even more fantastic than they had thought. “Even though I’m a theorist, I’m modest enough to acknowledge the fact that nature is sometimes more imaginative than we are,” Loeb says. “I’m open to surprises.”

    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 11:35 am on May 13, 2016 Permalink | Reply
    Tags: , , Radio Astronomy, , SKA selects the final design of the SKA dish   

    From SKA: “SKA selects the final design of the SKA dish” 

    SKA Square Kilometer Array

    SKA

    5.13.16
    No writer credit found

    SKA dishes final design
    SKA dishes final design
    An artist impression of the full SKA at night, with the selected Panel Space-frame supported Metal (PSM) SKA dish design in the foreground.

    [Unless the dish in the foreground of this photo is the final selection, we do not actually find any other image of the final selection.]

    SKA Global Headquarters, UK – The Square Kilometre Array (SKA) Project has selected the design for its dish, opening up the way for the eventual production of hundreds of dishes that will make up the world’s largest radio telescope.

    “This decision is a major milestone towards delivering the SKA,” said Alistair McPherson, Head of Project at SKA Organisation “Being able to “see” what the SKA dishes will look like for the first time is a big satisfaction for all involved.”

    Three antenna concepts were built to be considered for the design of the SKA dish: DVA-1 in Canada, DVA-C in China, and MeerKAT-1 in South Africa. All three were constructed using different technology from the different partners, representing the very best in radio telescope dish technology currently available.

    1
    DVA-1 in Canada

    3
    DVA-C in China

    SKA Meerkat telescope, South African design
    MeerKAT-1 in South Africa

    A five-strong selection panel of engineering experts in the fields of composites, radio telescope antennas and systems engineering assessed both designs on a series of indicators including surface accuracy, feasibility of on-site manufacturing and ability to maintain structural integrity over long time-frames and made a unanimous recommendation that the Chinese PSM concept should be selected for the SKA dishes, a recommendation that was then approved by the SKA Dish Consortium Board.

    The SKA Dish Consortium, made up of institutes from Australia (who leads the consortium), Canada, China, Germany, Italy and South Africa is responsible for the design and verification of the dish that will make up SKA-mid, one of two SKA instruments. In its first phase of deployment (SKA1), SKA-mid will be initially composed of 133 15-metre diameter dishes providing a continuous coverage from 350 MHz to 14 GHz.

    One of the greatest challenges faced by the consortium is the mass production of hundreds of these dishes, all with identical performance characteristics, and built to last and tolerate the harsh conditions of the remote arid areas in which they will operate for 50 years. Combined with achieving a large high precision collecting area at a competitive price, it’s a formidable technical and engineering challenge.

    “We’re confident the selected design will perform well in the harsh conditions of the Karoo in South Africa and will deliver the precision that the scientific community needs to answer the questions they’re trying to solve” said Roger Franzen, SKA Dish Consortium Lead.

    “The next step for us is to build and test a prototype at the South African site” he continued.

    The detailed design and manufacturing of such prototype, called SKA-P, is led by JLRAT/CETC54 in collaboration with the European companies MTM and Società Aerospaziale Mediterranea (SAM), and the Assembly, Integration and Verification of SKA-P will be done on site together with SKA SA team.

    “We expect the installation of SKA-P on the ground to happen by spring 2017”, said Roger Franzen. “Once satisfied with its performance, the project will be in a good position to go to tender and issue the contract for the mass production of 133 dishes to make up SKA1-mid.”

    Beyond the design of the dish structure, the consortium is also tasked with designing and testing optics, receivers and other elements of the dish. As part of that process, NRC continues its valuable contributions to single pixel feed (SPF) receivers/digitizers and cryogenic low noise amplifiers (LNAs).

    About the Design process

    In 2013, the SKA Organisation sent out requests to research organisations and commercial partners around the world to help design the SKA. Eleven international teams – called consortia – were established and each tasked with designing a critical element of the project, with each consortium composed of partners who are leaders in their fields.

    The consortium then presented the following designs for study:

    An innovative Single Skin, Rim supported Composite (SRC) concept led by the National Research Council of Canada (NRC), along with SED Systems of Canada and RPC Composites of Australia.
    An optimised Panel, Space-frame supported Metal (PSM) concept, led by a Shijiazhuang, China based team composed of JLRAT/CETC-54 along with their European partner, MT Mechatronics (MTM) of Mainz, Germany

    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 8:05 am on May 6, 2016 Permalink | Reply
    Tags: , , , , , Radio Astronomy   

    From Daily Galaxy: “China’s Journey to the Far Side of the Moon –“Will It Lead to the 1st Radio Telescope Beyond Earth?” 

    Daily Galaxy
    The Daily Galaxy

    May 05, 2016
    No writer credit found

    1
    Image credits: svs.gsfc.nasa.gov

    China’s Chang’e 4 mission to the far side of the moon, planned for sometime before 2020 could eventually lead to the placement of a radio telescope for use by astronomers, something that would help “fill a void” in man’s knowledge of the universe, according to Zou Yongliao with the Chinese Academy of Sciences’ moon exploration department during a September 2015 interview on state broadcaster CCTV.

    Chang'e 4 China
    Chang’e 4 China

    Radio transmissions from Earth are unable to reach the moon’s far side, making it an excellent location for sensitive instruments.China’s increasingly ambitious space program plans to attempt the first-ever landing of a lunar probe on the moon’s far side, a leading engineer said. Zou said the mission’s objective would be to study geological conditions on the moon’s far side.

    Topography of the near side (left) and far side (right) of moon shown below. On the map white and red colors represent high terrains and blue and purple are low terrains.

    2

    Meanwhile, back on Earth, China has constructed reflection panels for the world’s biggest radio telescope, the Five hundred meter Aperture Spherical Telescope (FAST).

    FAST Chinese Radio telescope under construction
    FAST Chinese Radio telescope under construction, Guizhou Province, China

    This radio telescope with an aperture of 500 meters is under construction in a natural basin in Guizhou Province. The telescope-under-construction has thousands of reflection panels; eventually the positions of these panels can be adjusted simultaneously to better receive radio waves from moving celestial bodies.

    The radio telescope will be twice as sensitive as the Arecibo Observatory operated by the United States.

    NAIC/Arecibo Observatory, Puerto Rico, USA
    NAIC/Arecibo Observatory, Puerto Rico, USA

    (Interestingly FAST was previously announced to become 3-times as sensitive, this is either a simple typing error or an adjustment in expectation.) The new telescope is also capable of collecting data even from the outer rim of the solar system. The telescope should be finished and installed by September 2016. As said, once successfully constructed the telescope will become the world’s largest and most sensitive radio telescope.

    It seems that the two sides of the moon have evolved differently since their formation, with the far side forming at cooler temperatures and remaining stiffer while the Earth side has been modified at higher temperatures and for longer. This information is extremely important for theories on the formation of the moon, of which the current favorite is the “Giant Impact” hypothesis.

    The Giant Impact idea is that four and a half billion years ago a planet the size of Mars [Theia] rammed Earth, kicking enough debris into orbit to accrete into an entirely new body. New research from geophysical scientist Junjun Zhang and colleagues at Origins Lab at the University of Chicago, suggests that the giant impact hypothesis of the creation of the Moon might be wrong. The team found that in comparing titanium isotopes from both the moon and the Earth, that the match is too close to support the theory that the moon could have been made partly of material from another planet.

    On the other hand, the researchers found that the Moon did show a similar composition of the silicon isotopic composition as the Earth. However, it, too, is much smaller than the Earth—about one-fiftieth as large as the Earth and about one percent of the Earth’s mass—making it even less likely to have been able to generate enough pressure to form an Earth-like iron core. This research was the first of its kind using isotopes in this manner and offers intriguing insights into the creation of Mars, the Earth, and the Moon. It may also help explain how life evolved on the Earth and whether or not it might have existed at some time on Mars..

    Because the moon is tidally locked (meaning the same side always faces Earth), it was not until 1959 that the farside was first imaged by the Soviet Luna 3 spacecraft (hence the Russian names for prominent farside features, such as Mare Moscoviense). And what a surprise -­ unlike the widespread maria on the nearside, basaltic volcanism was restricted to a relatively few, smaller regions on the farside, and the battered highlands crust dominated. A different world from what we saw from Earth.

    China’s next lunar mission is scheduled for 2017, when it will attempt to land an unmanned spaceship on the moon before returning to Earth with samples. If successful, that would make China only the third country after the United States and Russia to have carried out such a maneuver.

    See the full article here .

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  • richardmitnick 11:29 am on May 5, 2016 Permalink | Reply
    Tags: , , , , Radio Astronomy   

    From CSIRO: “Australian technology focal to the world’s largest telescope” 

    CSIRO bloc

    Commonwealth Scientific and Industrial Research Organisation

    5th May 2016
    Fiona McFarlane

    FAST Chinese Radio telescope under construction
    FAST Chinese Radio telescope under construction

    A powerful new 19-beam telescope receiver made and built by our engineers will lie at the heart of the world’s largest single-dish telescope.

    Half a kilometre wide, China’s new radio telescope is 195 metres wider than the Arecibo Observatory, famously used in several high profile movies throughout the 1990’s, including James Bond’s ‘GoldenEye’, and ‘Contact’, starring Jodie Foster as a SETI scientist. The ‘Five hundred metre Aperture Spherical Telescope’ (FAST) being developed by China’s leading astronomical research organisation (NAOC) will be the biggest ever created when it is completed later this year.

    2

    It will also be one of the most sensitive, able to receive weaker and more distant radio signals, helping to search for intelligent life outside of the galaxy and explore the origins of the universe. While the half-kilometre FAST dish might have been made in China, the receiver — the eye at its centre — was made here in Australia.

    3
    A fish-eye of the FAST reflector cable-net.

    The receiver detects the radio waves and was built by our engineers, following an agreement with the National Astronomical Observatories of the Chinese Academy of Sciences (NAOC) in China. Most radio telescopes use receivers that can only see one piece of the sky at a time but our scientists have designed receivers with many separate, simultaneous beams making it practical to search a large portion of the sky for faint and hidden galaxies.

    “The powerful 19-beam design we’ve created for FAST was possible because of our previous experience in designing and building receivers, including the 13 beam receiver developed for our own Parkes telescope,” Dr Douglas Bock, Acting Director at CSIRO Astronomy and Space Science said.

    “Working with China to design the centrepiece receiver system for FAST is not the first time we have worked with an international partner. We designed and delivered a multi-pixel receiver for Cornell University’s Arecibo radio telescope in Puerto Rico, which made it possible to scan the heavens seven times faster than before.”

    “Once FAST is finished and the receiver installed, it will be the most sensitive radio telescope in the world, three times more sensitive than the Arecibo Observatory,” Dr Bock said.

    NAIC/Arecibo Observatory
    NAIC/Arecibo Observatory

    FAST provides China with the technology to search for a range of signals including detecting thousands of new pulsars in our Galaxy and possibly the first radio pulsars in other galaxies.

    Our collaboration with China follows a similar agreement with Germany, where our award-winning Phased Array Feed (PAF) receiver technology will soon adorn the Max Planck Institute for Radioastronomy’s (MPIfR) Effelsberg telescope in Germany, the largest single-dish antenna in Europe.

    Parkes Phased Array Feed
    Parkes Phased Array Feed

    MPIFR/Effelsberg Radio Telescope
    MPIFR/Effelsberg Radio Telescope

    It’s exciting that technology designed and made in Australia is helping to detect and amplify radio waves and turn them into signals that astronomers use to expand our understanding of the Universe. What wonders FAST will reveal, we can only imagine. Watch this space

    See the full article here .

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    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 11:13 am on May 5, 2016 Permalink | Reply
    Tags: , , , , , Radio Astronomy   

    From ALMA: “ALMA Measures Mass of Black Hole with Extreme Precision” 

    ALMA Array

    ALMA

    05 May 2016

    Nicolás Lira T.
    Education and Public Outreach Coordinator
    Joint ALMA Observatory
    Santiago, Chile
    Tel: +56 2 2467 6519
    Cell: +56 9 9445 7726
    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
    Combined image of NGC 1332 shows the central disk of gas surrounding the supermassive black hole at the center of the galaxy. New ALMA observations traced the motion of the disk, providing remarkably precise measurements of the black hole’s mass: 660 million times the mass of our Sun. The main image is from the Carnegie-Irvine Galaxy Survey. The box in the upper left is from the Hubble Space Telescope and shows the galaxy’s central region in infrared light and the dusty disk appears as a dark silhouette. The ALMA image, upper right box, shows the rotation of the disk, enabling astronomers to calculate its mass. The red region in the ALMA image represents emission that has been redshifted by gas rotating away from us; the blue represents blue-shifted gas rotating toward us. The range of colors represent rotational speeds up to 500 kilometers per second. Credit: A. Barth (UC Irvine), ALMA (NRAO/ESO/NAOJ); NASA/ESA Hubble; Carnegie-Irvine Galaxy Survey.

    3
    DSS image of lenticular galaxy NGC 1332 and part of elliptical galaxy NGC 1331. Celestial Atlas.

    Supermassive black holes, some weighing millions to billions of times the mass of the Sun, dominate the centers of their host galaxies. To determine the actual mass of a supermassive black hole, astronomers must measure the strength of its gravitational pull on the stars and clouds of gas that swarm around it.

    Using the Atacama Large Millimeter/submillimeter Array (ALMA), a team of astronomers has delved remarkably deep into the heart of a nearby elliptical galaxy to study the motion of a disk of cold interstellar gas encircling the supermassive black hole at its center. These observations provide one of the most accurate mass measurements to date for a black hole outside of our Galaxy, helping set the scale for these cosmic behemoths.

    To obtain this result, Aaron Barth, an astronomer at the University of California, Irvine (UCI), and lead author on a paper published* in the Astrophysical Journal Letters, and his team used ALMA to measure the speed of carbon monoxide gas in orbit around the black hole at the center of NGC 1332, a massive elliptical galaxy approximately 73 million light-years from Earth in the direction of the southern constellation Eridanus.

    “Measuring the mass of a black hole accurately is very challenging, even with the most powerful telescopes on Earth or in space,” Barth said. “ALMA has the revolutionary ability to observe disks of cold gas around supermassive black holes at small enough scales that we can clearly distinguish the black hole’s influence on the disk’s rotational speed.”

    The ALMA observations reveal details of the disk’s structure on the order of 16 light-years across. They also measure the disk’s rotation well within the estimated 80 light-year radius of the black hole’s “sphere of influence” – the region where the black hole’s gravity is dominant.

    Near the disk’s center, ALMA observed the gas traveling at more than 500 kilometers per second. By comparing these data with simulations, the astronomers calculated that the black hole at the center of NGC 1332 has a mass 660 million times greater than our Sun, plus or minus ten percent. This is about 150 times the mass of the black hole at the center of the Milky Way, yet still comparatively modest relative to the largest black holes known to exist, which can be many billions of solar masses.

    ALMA’s close-in observations were essential, the researchers note, to avoid confounding the black hole measurement with the gravitational influence of other material – stars, clouds of interstellar gas, and dark matter – that comprises most of the galaxy’s overall mass.

    “This black hole, though individually massive, accounts for less one percent of the mass of all the stars in the galaxy,” noted Barth. “Most of a galaxy’s mass is in the form of dark matter and stars, and on the scale of an entire galaxy, even a giant black hole is just a tiny speck in the center. The key to detecting the influence of the black hole is to observe orbital motion on such small scales that the black hole’s gravitational pull is the dominant force.” This observation is the first demonstration of this capability for ALMA.

    Astronomers use various techniques to measure the mass of black holes. All of them, however, rely on tracing the motion of objects as close to the black hole as possible. In the Milky Way, powerful ground-based telescopes using adaptive optics can image individual stars near the galactic center and precisely track their trajectories over time. Though remarkably accurate, this technique is feasible only within our own Galaxy; other galaxies are too distant to distinguish the motion of individual stars.

    To make similar measurements in other galaxies, astronomers either examine the aggregate motion of stars in a galaxy’s central region, or trace the motion of gas disks and mega-masers — natural cosmic radio sources.

    Previous studies of NGC 1332 with ground- and space-based telescopes gave wildly different estimates for the mass of this black hole, ranging from 500 million to 1.5 billion times the mass of the Sun.

    The new ALMA data confirm that the lower estimates are more accurate.

    Crucially, the new ALMA observations have higher resolution than any of the past observations. ALMA also detects the emission from the densest, coldest component of the disk, which is in a remarkably orderly circular motion around the black hole.

    Many past measurements made with optical telescopes, including the Hubble Space Telescope, focused on the emission from the hot, ionized gas orbiting in the central region of a galaxy. Ionized-gas disks tend to be much more turbulent than cold disks, which leads to lower precision when measuring a black hole’s mass.

    “ALMA can map out the rotation of gas disks in galaxy centers with even sharper resolution than the Hubble Space Telescope,” noted UCI graduate student Benjamin Boizelle, a co-author on the study. “This observation demonstrates a technique that can be applied to many other galaxies to measure the masses of supermassive black holes to remarkable precision.”

    Additional information

    These results were published* in the Astrophysical Journal Letters as Measurement of the black hole mass in NGC 1332 from ALMA observations at 0.044 arcsecond resolution, by Aaron Barth et al.

    The team is composed of Aaron Barth (University of California, Irvine), Benjamin D. Boizelle (University of California, Irvine), Jeremy Darling (University of Colorado, Boulder), Andrew J. Baker (Rutgers, the State University of New Jersey, Piscataway), David A. Buote (University of California, Irvine), Luis Ho (Kavli Institute of Astronomy and Astrophysics, Peking University, China), and Jonelle L. Walsh (Texas A&M University, College Station).

    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.

    NRAO Small

    ESO 50

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  • richardmitnick 10:55 am on April 29, 2016 Permalink | Reply
    Tags: , , , , Radio Astronomy   

    From NRAO: “Gravitational Wave Search Provides Insights into Galaxy Evolution and Mergers” 

    NRAO Icon
    National Radio Astronomy Observatory

    NRAO Banner

    5 April 2016
    Elizabeth Ferrara
    NANOGrav press officer
    elizabeth.ferrara@nanograv.org
    301-286-7057

    Charles Blue
    NRAO Public Information Officer
    cblue@nrao.edu
    (434) 296-0314

    1
    The Earth is constantly jostled by low-frequency gravitational waves from supermassive black hole binaries in distant galaxies. Astrophysicists are using pulsars as a galaxy-sized detector to measure the Earth’s motion from these waves. Credit: B. Saxton (NRAO/AUI/NSF)

    Summary: New results from NANOGrav – the North American Nanohertz Observatory for Gravitational Waves – establish astrophysically significant limits in the search for low-frequency gravitational waves. This result provides insight into how often galaxies merge and how those merging galaxies evolve over time. To obtain this result, scientists required an exquisitely precise, nine-year pulsar-monitoring campaign conducted by two of the most sensitive radio telescopes on Earth, the Green Bank Telescope in West Virginia and the Arecibo Observatory in Puerto Rico.

    NRAO/GBT
    NRAO/GBT, West Virginia, USA

    NAIC/Arecibo Observatory
    NAIC/Arecibo Observatory, Puerto Rico, USA

    The recent LIGO detection of gravitational waves from merging black holes with tens of solar masses has confirmed that distortions in the fabric of space-time can be observed and measured [1].

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

    Caltech/MIT Advanced aLIGO Hanford Washington USA installation
    Caltech/MIT Advanced aLIGO Hanford Washington USA installation

    Researchers from the North American Nanohertz Observatory for Gravitational Waves (NANOGrav) have spent the past decade searching for low-frequency gravitational waves emitted by black hole binaries with masses many millions of times larger than those seen by LIGO.

    Analysis of NANOGrav’s nine-year dataset provides very constraining limits on the prevalence of such supermassive black hole binaries throughout the Universe. Given scientists’ current understanding of how often galaxies merge, these limits point to fewer detectable supermassive black hole binaries than were previously expected. This result has significant impacts on our understanding of how galaxies and their central black holes co-evolve.

    Low-frequency gravitational waves are very difficult to detect, with wavelengths spanning light-years and originating from black hole binaries in galaxies spread across the sky. The combination of all these giant binary black holes leads to a constant “hum” of gravitational waves that models predict should be detectable at Earth. Astrophysicists call this effect the “stochastic gravitational wave background,” and detecting it requires special analysis techniques.

    Pulsars are the cores of massive stars left behind after stars go supernova. The fastest pulsars rotate hundreds of times each second and emit a pulse of radio waves every few milliseconds. These millisecond pulsars (MSPs) are considered nature’s most precise clocks and are ideal for detecting the small signal from gravitational waves. “This measurement is possible because the gravitational wave background imprints a unique signature onto the radio waves seen from a collection of MSPs,” said Justin Ellis, Einstein Fellow at NASA’s Jet Propulsion Laboratory, California Institute of Technology in Pasadena, California, and a co-author on the report published in Astrophysical Journal.

    Astrophysicists use computer models to predict how often galaxies merge and form supermassive black hole binaries. Those models use several simplifying assumptions about how black hole binaries evolve when they predict the strength of the stochastic gravitational wave background. By using information about galaxy mergers and constraints on the background, the scientists are able to improve their assumptions about black hole binary evolution.

    Ellis continues: “After nine years of observing a collection of MSPs, we haven’t detected the stochastic background but we are beginning to rule out many predictions based on current models of galaxy evolution. We are now at a point where the non-detection of gravitational waves is actually improving our understanding of black hole binary evolution.”

    “Pulsar timing arrays like NANOGrav are making novel observations of the evolution and nature of our Universe,” says Sarah Burke Spolaor, Jansky Fellow at the National Radio Astronomy Observatory (NRAO) in Socorro, New Mexico, and a co-author on the paper.

    According to Spolaor, there are two possible interpretations of this non-detection. “Some supermassive black hole binaries may not be in circular orbits or are significantly interacting with gas or stars. This would drive them to merge faster than simple models have assumed in the past,” she said. An alternate explanation is that many of these binaries inspiral too slowly to ever emit detectable gravitational waves.

    NANOGrav is currently monitoring 54 pulsars, using the National Science Foundation’s Green Bank Telescope in West Virginia and Arecibo Radio Observatory in Puerto Rico, the two most sensitive radio telescopes at these frequencies [2]. Their array of pulsars is continually growing as new MSPs are discovered. In addition, the group collaborates with radio astronomers in Europe and Australia as part of the International Pulsar Timing Array, giving them access to many more pulsar observations. Ellis estimates that this increase in sensitivity could lead to a detection in as little as five years.

    In addition, this measurement helps constrain the properties of cosmic strings, very dense and thin cosmological objects, which many theorists believe evolved when the Universe was just a fraction of a second old. These strings can form loops, which then decay through gravitational wave emission. The most conservative NANOGrav limit on cosmic string tension is the most stringent limit to date, and will continue to improve as NANOGrav continues operating.

    “These new results from NANOGrav have the most important astrophysical implications yet,” said Scott Ransom, an astronomer with the NRAO in Charlottesville, Virginia. “As we improve our detection capabilities, we get closer and closer to that important threshold where the cosmic murmur begins to be heard. At that point, we’ll be able to perform entirely new types of physics experiments on cosmic scales and open up a new window on the Universe, just like LIGO just did for high-frequency gravitational waves.”

    NANOGrav is a collaboration of over 60 scientists at over a dozen institutions in the United States and Canada whose goal is detecting low-frequency gravitational waves to open a new window on the Universe. The group uses radio pulsar timing observations to search for the ripples in the fabric of spacetime. In 2015, NANOGrav was awarded $14.5 million by the National Science Foundation (NSF) to create and operate a Physics Frontiers Center.

    The Physics Frontier Centers bring people together to address frontier science, and NANOGrav’s work in low-frequency gravitational wave physics is a great example,” said Jean Cottam Allen, the NSF program director who oversees the Physics Frontiers Center program. “We’re delighted with their progress thus far, and we’re excited to see where it will lead.”

    1. # #

    Notes

    [1] LIGO is the Laser Interferometer Gravitational-Wave Observatory (https://www.ligo.caltech.edu)
    Press Release: Gravitational waves detected 100 years after Einstein’s prediction http://www.nsf.gov/news/news_summ.jsp?cntn_id=137628&org=NSF&from=news

    [2] National Science Foundation (http://www.nsf.gov)
    Press Release: Advancing physics frontiers: Newest collaborative centers set to blaze trails in basic research
    http://www.nsf.gov/news/news_summ.jsp?cntn_id=134586

    Reference:
    The NANOGrave Nine-year Data Set: Limits on the Isotropic Stochastic Gravitational Wave Background, Z. Arzoumanian et al., 2016, appears in the Astrophysical Journal http://iopscience.iop.org/journal/0004-637X.

    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

    NRAO GBT
    NRAO GBT

    NRAO VLA
    NRAO VLA

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

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

     
  • richardmitnick 2:19 pm on April 27, 2016 Permalink | Reply
    Tags: Astronomers detect mass of one quadrillion Earths, , , , Radio Astronomy   

    From CSIRO: “Astronomers detect mass of one quadrillion Earths” 

    CSIRO bloc

    Commonwealth Scientific and Industrial Research Organisation

    27th April 2016
    Fiona McFarlane

    SKA ASKAP Phased Array
    SKA ASKAP Phased Array

    Our scientists have weighed in on the idea of measuring a supermassive black hole and it’s come in at a whopping 3.8 billion solar masses – equivalent to one quadrillion Earths.

    At this mass the supermassive black hole at the centre of the distant galaxy being studied, outweighs our own Milky Way’s supermassive black hole by a factor of approximately 1000, estimated at a mass of just 4 million suns. Maybe it’s just as well our closest black hole is relatively small given the fact that material that gets too close gets sucked in and can never escape – a fact put to good use by the Simpsons. Fortunately for us, astronomers assure us that Earth won’t be sucked in anytime soon.

    But how did our scientists actually get to weigh one of these fascinating and mysterious objects?

    Dr Lisa Harvey-Smith, one of our astronomers working on the ASKAP project, made the measurement using the ASKAP and the Australia Telescope Compact Array (ATCA).

    SKA ASKAP telescope
    SKA ASKAP radio telescope

    Australia Telescope Compact Array
    Australia Telescope Compact Array

    What is a mega-maser?

    An astronomical maser can be described simply as clouds of gas that are amplifying radio waves and creating a luminous effect. They are not a single object in a galaxy but more an effect that is occurring in gas clouds throughout the inner regions of the galaxy.
    What causes a mega-maser?

    This particular mega-maser is a result of a trio of spiral galaxies colliding, causing a disruption and in turn a burst of star formation, resulting in a mega-maser at the centre of the range of galaxies in this system.

    A mega-maser is one million times more luminous than the masers we see in our own Galaxy.

    What does the mega-maser have to do with weighing a black hole?

    The clouds of gas that make up the mega-maser are rotating around the black hole in the centre of this distant galaxy. By measuring the speed of their rotation and using a simple mathematical equation, scientists can estimate the mass of the black hole, which in this case turned out to be a super massive black hole with a mass of approximately 3.8 billion suns.

    In the last decade, scientists have come to believe that black holes are not only common throughout the Universe but they play a fundamental role in the formation and evolution of galaxies like the Milky Way Universe that we inhabit today.

    And ASKAP is key to our ability to unlock further secrets and uncover new phenomena that will help us understand the nature of life on earth.

    ASKAP, ACTA and SKA

    An important angle of this research is that it has demonstrated the capacity of ASKAP to provide the data needed by astronomers to study some fundamental questions about the evolution of our Universe. To be sure that the data are accurate, there need to be checks and balances to ensure the ASKAP technology is working as planned. To do this, the team compared two independent data sets, one captured by ASKAP BETA’s array and the other captured by ATCA.

    The results matched, confirming that ASKAP is working as hoped, fulfilling one of its key roles of pioneering revolutionary new technologies as part of Australia’s contribution to the design and development of the international SKA project.

    SKA Square Kilometer Array
    SKA Square Kilometer Array

    For more information about ASKAP, visit our website.

    See the full article here .

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  • richardmitnick 7:31 pm on April 20, 2016 Permalink | Reply
    Tags: , , , Dusty doughnut around massive black hole spied for first time, , Radio Astronomy   

    From New Scientist: “Dusty doughnut around massive black hole spied for first time” 

    NewScientist

    New Scientist

    20 April 2016
    Shannon Hall

    1
    A dusty doughnut might look like this. NASA/JPL-Caltech

    It won’t taste very good. We have for the first time imaged one of the doughnuts of dust long thought to encircle some supermassive black holes.

    Astronomers think all galaxies are “active” at some point in their lifetimes, meaning that the central supermassive black hole feeds on a circling disc of gas. Although that disc can be so bright that it outshines the entire galaxy, some seem to be obscured by a doughnut-shaped structure of dust and gas, called a “torus.” Yet because the centres of these active galaxies are so distant, a dusty torus has never been seen – until now.

    Santiago Garcia-Burillo of Spain’s Madrid Observatory and his colleagues used a radio telescope array to image the torus of NGC 1068, a galaxy 50 million light years away. Although it is one of the brightest and nearest active galaxies, its torus still appears tens of thousands of times smaller than the moon.

    The discovery required 35 radio dishes on the Atacama Large Millimeter/submillimeter Array (ALMA) perched in the high desert of the Chilean Andes.

    ESO/NRAO/NAOJ ALMA Array
    ESO/NRAO/NAOJ ALMA Array

    “It’s an absolutely remarkable observation,” says Jack Gallimore of Bucknell University in Lewisburg, Pennsylvania. “It’s a real testament to how much of a powerhouse ALMA is.”

    It should also shed light on a long-standing problem in astrophysics, namely what causes a galaxy to become active, says Gallimore. Although we know that clouds of gas must fall from the galaxy towards the supermassive black hole, it’s not that simple.

    As the gas falls inward, it spins faster, allowing it to reach a circular velocity like Earth’s orbit around the sun. “A cloud would eventually be spinning so fast that it would just achieve a stable orbit around the black hole,” says Gallimore. “So that prevents it from falling in and feeding the black hole.”

    And yet these supermassive black holes actively accrete gas and dust – enough to grow to millions or billions of times the sun’s mass. So if astronomers can see how gas flows through the torus, they are likely to get a better handle on what sparks the black hole feeding frenzy behind an active galaxy.

    Science paper:
    ALMA resolves the torus of NGC 1068: continuum and molecular line emission

    See the full article here .

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  • richardmitnick 1:31 pm on April 20, 2016 Permalink | Reply
    Tags: , , , Could Fast Radio Bursts be of cosmological origin?, Radio Astronomy   

    From CAASTRO: “Could Fast Radio Bursts be of cosmological origin?” 

    CAASTRO bloc

    CAASTRO ARC Centre of Excellence for All Sky Astrophysics

    High time resolution radio surveys over the last decade have discovered a population of millisecond-duration transient bursts called Fast Radio Bursts (FRBs) of unknown. Only 18 of these bursts have been detected to date, and their origin – whether extragalactic or at even cosmological distances – is still uncertain.

    CAASTRO PhD student Manisha Caleb (ANU and Swinburne University of Technology) and colleagues have now scrutinised the FRB properties: energy distribution, spatial density as a function of redshift and properties of the Interstellar and Intergalactic Media. The researchers ran simulations to test whether a cosmological population is a feasible scenario and to compare their simulations to data from the High Time Resolution Universe survey that used the Effelsberg radio telescope in Germany and the 64-m Parkes radio telescope in Australia.

    MPIFR/Effelsberg Radio Telescope
    MPIFR/Effelsberg Radio Telescope

    CSIRO/Parkes Observatory
    CSIRO/Parkes Observatory

    Their Monte Carlo simulations were based on two scenarios for the co-moving numbers of FRBs: a constant co-moving density model and a model in which the number of FRBs is proportional to the known cosmic star formation history (SFH). The most interesting property of the simulated events is their distribution of detections above some fluence (so-called logN-logF curves): if the sources have an even approximately typical luminosity (i.e. are standard candle-like), then the slope of this relation is a probe of their spatial distribution. For standard candles in the standard model of cosmology – LCDM – the slope varies smoothly from -3/2 for the nearby universe, gradually becoming flatter as further distances are probed. To illustrate, at a redshift of z ~0.7, which is typical of FRBs found to date, standard candles yield a relation with a slope of ~ -1. The observed slope of the logN-logF of the 9 FRBs analysed in this study is -0.9 +/- 0.3. The team’s simulations were able, in both scenarios for the number density of the sources with redshift, to match this slope well, yielding -0.8 +/- 0.3 for the cosmic SFH and -0.7 +/- 0.2 for the constant density case. They concluded that the properties of the observed FRBs are generally consistent with arising from sources at cosmological distances.

    The researchers also simulated FRB rates at the upgraded Molonglo telescope, UTMOST, and at Parkes for the Multibeam and the planned Phased Array Feed (PAF) receivers.

    Molonglo Observatory Synthesis Telescope (MOST)
    Molonglo Observatory Synthesis Telescope (MOST)

    Parkes Phased Array Feed
    Parkes Phased Array Feed

    They applied conservative assumptions about the spectral index of FRBs and the sensitivity of the instruments. According to those simulations, UTMOST has the capability, at full design sensitivity, to dominate the FRB detection rate. Uncertainty in the final PAF design sensitivity make predictions difficult for Parkes but its wide sky coverage has the potential to increase the FRB discovery rate close to the fluence limit. The fully sensitive UTMOST will dominate the event detection rate at all fluences.

    See the full article here .

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    Stem Education Coalition

    Astronomy is entering a golden age, in which we seek to understand the complete evolution of the Universe and its constituents. But the key unsolved questions in astronomy demand entirely new approaches that require enormous data sets covering the entire sky.

    In the last few years, Australia has invested more than $400 million both in innovative wide-field telescopes and in the powerful computers needed to process the resulting torrents of data. Using these new tools, Australia now has the chance to establish itself at the vanguard of the upcoming information revolution centred on all-sky astrophysics.

    CAASTRO has assembled the world-class team who will now lead the flagship scientific experiments on these new wide-field facilities. We will deliver transformational new science by bringing together unique expertise in radio astronomy, optical astronomy, theoretical astrophysics and computation and by coupling all these capabilities to the powerful technology in which Australia has recently invested.

    PARTNER LINKS

    The University of Sydney
    The University of Western Australia
    The University of Melbourne
    Swinburne University of Technology
    The Australian National University
    Curtin University
    University of Queensland

     
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