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  • richardmitnick 2:50 am on February 10, 2016 Permalink | Reply
    Tags: , , , , Radio Astronomy   

    From perth now for CSIRO: “Australian astronomers zero-in on the ‘Great Attractor’ pulling on our Milky Way” 

    perth now

    perth now

    CSIRO bloc

    Commonwealth Scientific and Industrial Research Organisation

    February 9, 2016
    Jamie Seidel

    A STRANGE intergalactic force is drawing our Milky Way galaxy inward. We don’t know what, or why. But a hidden swarm of hundreds of nearby galaxies just discovered by Australian astronomers may help reveal the identity of the ‘Great Attractor’.

    Great Attractor galaxies

    This pack of galaxies has been spotted by International Centre for Radio Astronomy Research (ICRAR) researchers using CSIRO’s Parkes Observatory in NSW.

    CSIRO Parkes Observatory

    The study was published today in Astronomical Journal.

    Despite being ‘just next door’ in astronomical terms — a mere 250 million light years away — these galaxies have remained hidden from view because they are on the opposite side of our own.

    The intensity of stars and dust crowded together along the plane of the Milky Way is directly in the line of sight — masking everything behind it from view.

    That something must be there has been known for some time.

    Its immense gravitational pull — the equivalent of a million billion Suns — has been observed through calculations of strange deviations in the flight path of nearby galaxies.

    And our own.

    In the absence of any indication as to what it may be, astronomers have simply dubbed it the Great Attractor.

    Universe map
    Panoramic view of the entire near-infrared sky. The location of the Great Attractor is shown following the long blue arrow at bottom-right.

    Our Milky Way is just one of hundreds of thousands of local galaxies ensnared by its grasp.

    And we’re hurtling towards the mysterious source of this attraction force at more than two million kilometres per hour.

    GREAT ATTRACTOR

    “We don’t actually understand what’s causing this gravitational acceleration on the Milky Way or where it’s coming from,” says study lead author Professor Lister Staveley-Smith of the University of Western Australia.

    “We know that in this region there are a few very large collections of galaxies we call clusters or superclusters, and our whole Milky Way is moving towards them.”

    Superclusters
    Superclusters

    Essentially, all we know is that there is an immense — but probably diffuse — concentration of mass lurking some 250 million light years away.

    Is it a monster-black hole? Or a whole army of these collapsed points in space-time?

    “Some astronomers think the Great Attractor is a super-supercluster of galaxies; some astronomers think that some regions of the universe are “darker” than others,” Professor Staveley-Smith says, referring to densities of the invisible source of gravity dubbed Dark Matter.

    “Some physicists are even considering the possibility that the mass fluctuations in the universe are so significant that astronomers may be fundamentally misinterpreting the relationship between gravity and motion.”

    It all remains speculation.

    But observing and understanding the distribution and behaviour of the new galaxies may uncover vital clues.

    “The ‘Great Attractor’ lies at the intersection of several large-scale filaments of galaxies,” says Dr Barbel Koribalski of CSIRO Astronomy and Space Science. “One could picture a giant hoover with galaxies near and far slowly streaming towards it. We can’t see much of this hoover, but we can measure the motion of the galaxies.”

    What is doing the hoovering is the issue.

    SUPER SIGHT

    The Parkes radio telescope is a 64-metre dish that was activated in 1961. It was more recently modified with an innovative receiver, allowing the international team of scientists to peer past the ‘interference’ of our galactic core into unexplored space.

    “The Milky Way is very beautiful of course and it’s very interesting to study our own galaxy but it completely blocks out the view of the more distant galaxies behind it,” says Professor Staveley-Smith.

    Not so completely anymore.

    What the survey revealed was a field of 883 galaxies, a third of which had not previously been suspected says Professor Staveley-Smith.

    University of Cape Town astronomer Professor Renée Kraan-Korteweg — also part of the research team — said astronomers have been trying to map the galaxies hidden behind the Milky Way for decades.

    “We’ve used a range of techniques but only radio observations have really succeeded in allowing us to see through the thickest foreground layer of dust and stars,” she said.

    “An average galaxy contains 100 billion stars, so finding hundreds of new galaxies hidden behind the Milky Way points to a lot of mass we didn’t know about until now.”

    So what caused this odd accumulation of galaxies?

    That bit remains the problem.

    BIONIC EYE

    Dr Koribalski says innovative technologies on the Parkes radio telescope had made it possible to survey large areas of the sky quickly. And things are about to get much, much better.

    “Detecting galaxies behind the Milky Way (in the so-called Zone of Avoidance) and measuring their motions is important to pinpoint its location and total mass,” she says. “The Parkes multibeam system made this possible. With this receiver we’re able to map the sky 13 times faster than we could before and make new discoveries at a much greater rate.”

    Copies of this receiver have been purchased from CSIRO by United States and Chinese astronomers to upgrade their own radio telescopes.

    But this receiver is being temporarily removed from the Parkes telescope this week. A new Phased-Array Feed (PAF) is being attached for testing.

    Parkes Phased Array Feed

    “The PAF is a huge technological advance, a breakthrough of major proportion that will be able to do fast and sensitivities surveys of the sky, (and is) bound to make many new discoveries,” Dr Koribalski says. “How to learn more about the Great Attractor? The answer is WALLABY — the upcoming Australian SKA Pathfinder (ASKAP) HI All Sky Survey – which is expected to spot more than 500,000 galaxies.”

    SKA ASKAP telescope
    ASKAP

    This will offer much faster scanning of the skies than current equipment, combined with a twenty-fold increase in resolution.

    Dr Koribalski says she expects the new scope will detect an additional 10,000 galaxies tucked away behind our own.

    It may also, hopefully, paint a trail to the ‘Great Attractor’ itself.

    See the full article here .

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    CSIRO campus

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

     
  • richardmitnick 11:24 am on February 3, 2016 Permalink | Reply
    Tags: , , , IRAM, , Radio Astronomy   

    From ALMA: “The Frigid Flying Saucer” 

    ESO ALMA Array
    ALMA

    03 February 2016
    Stephane Guilloteau
    Laboratoire d’Astrophysique de Bordeaux
    Floirac, France
    Email: stephane.guilloteau@u-bordeaux.fr

    Emmanuel di Folco
    Laboratoire d’Astrophysique de Bordeaux
    Floirac, France
    Email: emmanuel.di-folco@u-bordeaux.fr

    Vincent Pietu
    IRAM
    Grenoble, France
    Email: pietu@iram.fr

    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

    Richard Hook
    Public Information Officer, ESO

    Garching bei München, Germany

    Tel: +49 89 3200 6655

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

    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

    ALMA Flying Saucer protoplanetary disc around 2MASS J16281370-2431391.
    The Flying Saucer protoplanetary disc around 2MASS J16281370-2431391. This close-up infrared view of the Flying Saucer comes from the NASA/ESA Hubble Space Telescope. Credit: ESO/NASA/ESA

    NASA Hubble Telescope
    NASA/ESA Hubble

    Astronomers have used the ALMA and IRAM telescopes to make the first direct measurement of the temperature of the large dust grains in the outer parts of a planet-forming disc around a young star. By applying a novel technique to observations of an object nicknamed the Flying Saucer they find that the grains are much colder than expected: –266 degrees Celsius. This surprising result suggests that models of these discs may need to be revised.

    The international team, led by Stephane Guilloteau at the Laboratoire d’Astrophysique de Bordeaux, France, measured the temperature of large dust grains around the young star 2MASS J16281370-2431391 in the spectacular Rho Ophiuchi star formation region, about 400 light-years from Earth.

    The Rho Ophiuchi star formation region in the constellation of Ophiuchus.
    The Rho Ophiuchi star formation region in the constellation of Ophiuchus. This wide-field view shows a spectacular region of dark and bright clouds, forming part of a region of star formation in the constellation of Ophiuchus (The Serpent Bearer). This picture was created from images in the Digitized Sky Survey 2. Credit: ESO/Digitized Sky Survey 2

    This star is surrounded by a disc of gas and dust — such discs are called protoplanetary discs as they are the early stages in the creation of planetary systems. This particular disc is seen nearly edge-on, and its appearance in visible light pictures has led to its being nicknamed the Flying Saucer.

    The astronomers used the Atacama Large Millimeter/submillimeter Array (ALMA) to observe the glow coming from carbon monoxide molecules in the 2MASS J16281370-2431391 disc. They were able to create very sharp images and found something strange — in some cases they saw a negative signal! Normally a negative signal is physically impossible, but in this case there is an explanation, which leads to a surprising conclusion.

    Lead author Stephane Guilloteau takes up the story: “This disc is not observed against a black and empty night sky. Instead it’s seen in silhouette in front of the glow of the Rho Ophiuchi Nebula. This diffuse glow is too extended to be detected by ALMA, but the disc absorbs it. The resulting negative signal means that parts of the disc are colder than the background. The Earth is quite literally in the shadow of the Flying Saucer!”

    The team combined the ALMA measurements of the disc with observations of the background glow made with the IRAM 30-metre telescope in Spain [1].

    IRAM 30m Radio telescope
    IRAM 30-metre telescope

    They derived a disc dust grain temperature of only –266 degrees Celsius (only 7 degrees above absolute zero, or 7 Kelvin) at a distance of about 15 billion kilometers from the central star [2]. This is the first direct measurement of the temperature of large grains (with sizes of about one millimeter) in such objects.

    This temperature is much lower than the –258 to –253 degrees Celsius (15 to 20 Kelvin) that most current models predict. To resolve the discrepancy, the large dust grains must have different properties than those currently assumed, to allow them to cool down to such low temperatures.

    “To work out the impact of this discovery on disc structure, we have to find what plausible dust properties can result in such low temperatures. We have a few ideas — for example the temperature may depend on grain size, with the bigger grains cooler than the smaller ones. But it is too early to be sure,” adds co-author Emmanuel di Folco (Laboratoire d’Astrophysique de Bordeaux).

    If these low dust temperatures are found to be a normal feature of protoplanetary discs this may have many consequences for understanding how they form and evolve.

    For example, different dust properties will affect what happens when these particles collide, and thus their role in providing the seeds for planet formation. Whether the required change in dust properties is significant or not in this respect cannot yet be assessed.

    Low dust temperatures can also have a major impact for the smaller dusty discs that are known to exist. If these discs are composed of mostly larger, but cooler, grains than is currently supposed, this would mean that these compact discs can be arbitrarily massive, so could still form giant planets comparatively close to the central star.

    Further observations are needed, but it seems that the cooler dust found by ALMA may have significant consequences for the understanding of protoplanetary discs.

    Notes

    [1] The IRAM measurements were needed as ALMA itself was not sensitive to the extended signal from the background.

    [2] This corresponds to one hundred times the distance from the Earth to the Sun. This region is now occupied by the Kuiper Belt within the Solar System.

    Kuiper Belt
    Known objects in the Kuiper belt beyond the orbit of Neptune. (Scale in AU; epoch as of January 2015.)

    Additional information

    This research was presented in a paper entitled The shadow of the Flying Saucer: A very low temperature for large dust grains, by S. Guilloteau et al., published in Astronomy & Astrophysics Letters.

    The team is composed of S. Guilloteau (University of Bordeaux/CNRS, Floirac, France), V. Piétu (IRAM, Saint Martin d’Hères, France), E. Chapillon (University of Bordeaux/CNRS; IRAM), E. Di Folco (University of Bordeaux/CNRS), A. Dutrey (University of Bordeaux/CNRS), T.Henning (Max Planck Institute für Astronomie, Heidelberg, Germany [MPIA]), D.Semenov (MPIA), T.Birnstiel (MPIA) and N. Grosso (Observatoire Astronomique de Strasbourg, Strasbourg, France).

    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 7:02 pm on January 27, 2016 Permalink | Reply
    Tags: , , , , Radio Astronomy,   

    From WIRED.com: “The Death of General Relativity Lurks in a Black Hole’s Shadow” 

    Wired logo

    Wired

    01.27.16
    Lizzie Wade

    Black hole in color
    Chi-kwan Chan, Feryal Ozel, and Dimitrios Psaltis

    Nothing gets out of a black hole—not even light. Once a star, a planet, a piece of dust, or even a single photon crosses the limit known as the event horizon, it’s not coming out again. Pulled into the crushing gravity of the singularity at the black hole’s heart, it vanishes from the universe.

    That’s a big problem if what you really want from a black hole is a photograph. By definition, it’s impossible. All light getting sucked in means no light reflects back—so a black hole is invisible, across the spectrum. And, duh, invisible objects don’t show up in photographs.

    But thanks to a new telescope, Tim Johannsen, an astrophysicist at the Perimeter Institute and the University of Waterloo in Ontario, Canada, may be able to get a black hole pic after all. A loophole in physics means he might be able to see not the black hole itself, but its shadow. And, no big deal, but that photo just might overturn Albert Einstein’s theory of general relativity.

    So…wait. Black holes have shadows? Sort of. As gas and dust and other cosmic material approaches a black hole, “that stuff heats up, like millions and millions of degrees,” Johannsen says. That superheated matter swirls around the black hole in what’s called an accretion disk; because it’s so hot, the accretion disk emits a lot of light.

    Some of those photons zoom out towards Earthbound telescopes, while others cross the event horizon and fall into the void. So when astronomers look at a black hole, what they expect to see is a ring of bright light—the accretion disk—surrounding a circle of nothingness. That circle of nothingness is the shadow. (The black hole itself is just a single point within.) You can see a model of that here:


    Download mp4 video here .

    At least, that’s the idea. No one has ever actually seen a black hole’s shadow. “Despite their enormous mass, black holes are also exceedingly small,” says Avery Broderick, Johannsen’s colleague at the Perimeter Institute and the University of Waterloo. Seen from Earth, the shadow of Sagittarius A*, the supermassive black hole at the center of the Milky Way (also known as Sgr A*, which astrophysicists pronounce “Saj-A-star”) is just 1/35,000,000th the width of the Moon, or 50 microarcseconds wide.

    Sag A prime
    Sgr A*

    Here’s where that new telescope comes in. Maybe. Johannsen, Broderick, and their colleagues hope the Event Horizon Telescope will be able to resolve Sgr A*’s shadow. The EHT is actually nine [radio] telescopes (and counting), all working together and each located in a different spot on Earth.

    Event Horizon Telescope map
    EHT map

    Telescopes of the EHT

    ALMA

    ALMA Array
    APEX

    ESO APEX

    Arizona Radio Observatory (U. of Arizona)

    Arizona Radio Observatory

    Caltech Submillimeter Observatory

    Caltech Submillimeter Observatory

    CARMA

    CARMA Array

    Harvard Smithsonian Center for Astrophysics Submillimeter Array

    SMA Submillimeter Array

    Institut de Radioastronomie Millimetrique (IRAM) 30m

    IRAM

    James Clerk Maxwell Telescope (JCMT)

    The Large Millimeter Telescope Alfonso Serrano (LMT)

    Plateau de Bure interferometer

    IRAM Interferometer Submillimeter Array of Radio Telescopes

    South Pole Telescope]

    South Pole Telescope

    Coordinating those telescopes’ observations allows them to work as one big telescope that is, in essence, as big as the planet. The bigger your telescope, the higher your resolution. “The Event Horizon Telescope has the capability to produce the highest-resolution images in the history of astronomy”, Broderick says. “That means, for the first time, we can see what happens right down in the immediate vicinity of black hole event horizons.”

    Scientists working on the EHT hope to see images in the spring of 2017. But they already have some ideas of what they’ll get. General relativity describes gravity not as a force drawing two objects together, but rather as the warped spacetime that governs each of those objects movements.

    Spacetime with Gravity Probe B
    Artist concept of Gravity Probe B orbiting the Earth to measure space-time, a four-dimensional description of the universe including height, width, length, and time. NASA

    Concentrate a big enough mass in a small enough region of spacetime, and its gravity will be inescapably huge—voila, you’ve got a black hole. If that sounds weird to you, well, it took 50 years for astronomers to discover that black holes were real objects, not just a quirk of general relativity’s math.

    The problem is, general relativity is really good at describing giant things like stars, but breaks down utterly when it comes to really teeny tiny things like photons and quarks. To talk about those, you need a different theory: quantum mechanics. The central problem in physics today is that the theories are fundamentally incompatible. To figure that out, physicists are keen to find places where the theories overlap or break down—like, for example, the event horizon of a black hole.

    General relativity doesn’t just predict the existence of black holes. It also precisely describes the size and shape of their shadows. Sgr A*’s shadow is supposed to be perfectly circular and 50 microarcseconds wide. “What would it look like if general relativity were wrong?” wonders Broderick (and just about every other astrophysicist on the planet). There are two possibilities. “The shadow could be more egg shaped,” says Johannsen. “That would be a smoking gun for a GR violation.” It might also be slightly smaller or bigger than general relativity predicts. All he needs to figure it out is the picture from the EHT. (Johannsen and Broderick just published a paper outlining their strategy in Physical Review Letters.)

    And what if Sgr A*’s shadow doesn’t look the way general relativity says it should? Well, that would be great. If the results held up, physicists could start looking for alternative theories of gravity that did predict the shadow’s size and shape. Success wouldn’t mean the new theory would automatically be the successor to general relativity, of course. But it’s a good way to figure out which theories might be on the right track, so you can give their other predictions a closer look.

    Johannsen’s favorite possibility involves extra dimensions. A shortcoming of general relativity is that it doesn’t explain why gravity is so much weaker than the other fundamental forces. “Let’s assume there is another space dimension. Gravity would immediately penetrate that and become kind of diluted,” Johannsen says. In other words, gravity isn’t weak, it’s just working across more dimensions than the other forces. Amazingly, theories that predict those extra dimensions also predict a different size for Sgr A*’s shadow. In a couple years, finally proving—or falsifying—this weird new physics could “literally be as ‘easy’ as putting a ruler across the image,” Johannsen says.

    “We’re getting this amazing opportunity to finally put Einstein to the test around the most enigmatic and striking predictions of this theory,” Broderick says. If Einstein is wrong, general relativity won’t go away—it’s too good at what it does. It just won’t be the whole story anymore. Isaac Newton was plenty right about how gravity worked here on Earth; Einstein revolutionized our understanding of the universe. But the universe is big enough to have room for someone to come along and do it again.

    See the full article here .

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  • richardmitnick 4:43 pm on January 27, 2016 Permalink | Reply
    Tags: , , , , Radio Astronomy,   

    From U Cambridge via CfA: “The Event Horizon Telescope project” – Interview of Shep Doelman – Worth Your Time 

    HarvardSmithsonian

    Harvard-Smithsonian Center for Astrophysics

    U Cambridge bloc

    Cambridge University

    Shep Doelman, MIT Haystack Observatory and Harvard Smithsonian Centre for Astrophysics

    Event Horizon Telescope map
    EHT map

    The event horizon at the mouth of a black hole is the point of no return: once light crosses this threshold, there is no going back. This means it’s proved impossible for astronomers to physically see what’s going on beyond this point. But there might be a way to do it by looking at the shadow cast by the event horizon and using this to infer what made that shadow. Shep Doelman is an astronomer at the MIT Haystack Observatory and Harvard Smithsonian Centre for Astrophysics, and he’s part of an initiative called The Event Horizon Telescope project, which aims to get the first image of the shadow cast by the black hole at the centre of our own galaxy, as he explains to Georgia Mills…

    Shep – There’s a part of the Universe that is forever separate from our experience, and that’s inside inside the event horizon, and the size and the shape of that event horizon is predicted by [Albert] Einstein’s equations which have withstood all the tests that we’ve subjected them to in the solar system and the larger universe, and now we’d like to go to the one place where they might break down, at the event horizon itself.

    Georgia – Past the event horizon, by its very nature, you can’t really see into it. How would you be able to study something like that?

    Shep – Well, in a paradox of their own immense gravity, black holes, which by definition are dark are some of the brightest objects in the Universe. You can think of it this way: the black hole is insanely powerful and it’s trying to attract all of this gas, dust, and ionised plasma into a very small volume and you get a cosmic traffic jam. Everything is rubbing up against each each and, just as your hands get warm when you rub them together, all this gas and dust heats up to billions of degrees. So it’s a little bit like trying to suck an elephant through a straw; it’s very hard to do and, when you ultimately do it, it’s a big mess. So the black hole and the event horizon are illuminated by this three dimensional flashlight that lights up the space time, and one of the characteristics of the event horizon is that the light gets bent by gravity and so you wind up with a shadow feature. The way you can think about the shadow is that the light that is moving away from you, from the back side of the black hole, gets bent around in these curve trajectories back toward you so it illuminates a ring of light around the event horizon, and it’s the size and shape of that ring that we’re after with the Event Horizon Telescope Project.

    Georgia – So how are you planning to find this shadow?

    Shep – Black holes are the smallest objects that we know of and to see something that small you’ve got to make an entirely new kind of telescope. So we need something, to put it in perspective, that has a magnifying power that’s at least 2,000 times better than the Hubble Space Telescope.

    NASA Hubble Telescope
    NASA/ESA Hubble

    The best candidate for us to observe one of these black hole shadows is in the centre of our own Milky Way galaxy and radio waves are the perfect medium for that. They can pierce the gas, and the dust, and the ionised plasma that lies between us and the centre of our galaxy. So we need to make a telescope that has 2,000 times the magnifying power of the Hubble that sees radio waves.

    Georgia – So the problem here is that you need a radio telescope that’s 2,000 times stronger and that, to me, would seem like it would need to be bigger. How are you going to go about this?

    Shep – The magic of the Event Horizon Telescope is that we don’t make one single telescope, but we use radio dishes that are spread around the globe and we link them together using GPS to synchronise them perfectly, and then we install atomic clocks at each of the sites. And all of the telescopes swivel to look at the black hole at the centre of our galaxy at the same exact moment and, when that happens, you get an earth sized virtual telescope and the radio waves are recorded perfectly at each of the sites. Then hard discs are shipped back on a 747, or the airliner of your choice, to a central facility and when you do that we wind up getting a data set that’s equivalent to having a telescope the size of the Earth. And I would hasten to add that when you’re making and Earth sized telescope you need and Earth sized group and I’m just pleased as punch to work with some of the most talented astronomers on the face of the Earth from: Taiwan, Japan, Chile, the United States, Europe. It’s a really big enterprise.

    Georgia – This kind of massive collaboration thing; it seems to me that’s what science is all about. How did you get all these different telescopes on board with you?

    Shep – Part of the secret sauce of the Event Horizon Telescope is that we’re not building any new telescopes. We are developing all the instrumentation that allows us to turn telescopes that already exist into this global linked array. So, what we have done is we’ve gone to the directors and boards of telescopes around the world; we’ve explained this project to them and the science payoff is so interesting and exciting to the community that they’ve allowed us to come in with specialised equipment, install it at the telescopes and make these observations, and we’ve had some very interesting results so far. We wouldn’t really be having this conversation if we hadn’t already seen very small shadow sized features towards the black hole at the centre of the galaxy, and now we’re going to take those size measurements one step further and see if we can make an actual image.

    [Telescopes of the EHT

    ALMA

    ALMA Array
    APEX

    ESO APEX

    Arizona Radio Observatory (U. of Arizona)

    Arizona Radio Observatory

    Caltech Submillimeter Observatory

    Caltech Submillimeter Observatory

    CARMA

    CARMA Array

    Harvard Smithsonian Center for Astrophysics Submillimeter Array

    SMA Submillimeter Array

    Institut de Radioastronomie Millimetrique (IRAM) 30m

    IRAM

    James Clerk Maxwell Telescope (JCMT)

    The Large Millimeter Telescope Alfonso Serrano (LMT)

    Plateau de Bure interferometer

    IRAM Interferometer Submillimeter Array of Radio Telescopes

    South Pole Telescope]

    South Pole Telescope

    Georgia – And then at some point in the near future – well when is this going to happen, when are we going to get the telescopes to join up and assemble and all point at the same direction at once?

    Shep – Well we’re on, as they say, an aggressive timeline. We have already made these precursor observations which show us that we’re on the right track and we are, over the next year, finishing the build out across the entire global array. The first possibility for us to really make an image would be in the spring of 2017, that’s when of the larger telescopes (The Alma Array, in Chile), will join the Event Horizon Telescope and that will increase our sensitivity by a factor of ten, and also increase our resolution by a factor of two, and that would be the first time when we would have a shot at making a credible image. Knowing that all those 4 millions suns are within that ring would be the strongest evidence that we have, as least as humans (aliens might have better evidence), that black holes actually exist.

    See the full article here .

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    U Cambridge Campus

    The University of Cambridge[note 1] (abbreviated as Cantab in post-nominal letters[note 2]) is a collegiate public research university in Cambridge, England. Founded in 1209, Cambridge is the second-oldest university in the English-speaking world and the world’s fourth-oldest surviving university.[6] It grew out of an association of scholars who left the University of Oxford after a dispute with townsfolk.[7] The two ancient universities share many common features and are often jointly referred to as “Oxbridge”.

    Cambridge is formed from a variety of institutions which include 31 constituent colleges and over 100 academic departments organised into six schools.[8] The university occupies buildings throughout the town, many of which are of historical importance. The colleges are self-governing institutions founded as integral parts of the university. In the year ended 31 July 2014, the university had a total income of £1.51 billion, of which £371 million was from research grants and contracts. The central university and colleges have a combined endowment of around £4.9 billion, the largest of any university outside the United States.[9] Cambridge is a member of many associations and forms part of the “golden triangle” of leading English universities and Cambridge University Health Partners, an academic health science centre. The university is closely linked with the development of the high-tech business cluster known as “Silicon Fen”.

     
  • richardmitnick 11:45 am on January 27, 2016 Permalink | Reply
    Tags: , , , , , Radio Astronomy   

    From ALMA: “ALMA confirms predictions on the interaction between protoplanetary disks and planets” 

    ESO ALMA Array
    ALMA

    27 January 2016
    Héctor Cánovas
    Universidad de Valparaíso Valparaíso, Chile
    Tel: +56 032 – 299 5555
    Tel: +56 02 84144232
    E-mail: hector.canovas@uv.cl

    Valeria Foncea

    Education and Public Outreach Officer

    Joint ALMA Observatory

    Santiago, Chile

    Tel: +56 2 467 6258

    Cell: +56 9 75871963
    E-mail: vfoncea@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
    E-mail: 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

    Protoplanetary disc from ALMA
    Image taken by ALMA of the dust ring that surrounds the young star Sz 91. This ring is primarily made up of mm-sized dust particles. The interaction between several recently formed planets and the protoplanetary disk that still surrounds the star probably generate the dust ring observed by ALMA.

    New observations made with the Atacama Large Millimeter/submillimeter Array (ALMA) of the disk that surrounds a young star, less massive than the Sun, confirm theories about the interaction between recently formed planets and disks. A team of astronomers led by Héctor Cánovas from Universidad de Valparaíso and the Millennium ALMA Disk Nucleus (MAD) observed the dust ring possibly sculpted by planets in formation around the star Sz 91, at a distance roughly 650 light years from Earth.

    The results obtained show the first disk around a star that is less massive than ours – it has only half of the mass of our Sun – which simultaneously presents a migration of dust particles from the outermost zones and evident signs of interaction between young planets with the disk in the innermost zone.

    Planets are born in dust and gas disks that surround young stars and feed them with matter, leaving a “footprint” of this interaction in the structure of the disk. The theoretical models that study this interaction predict that the planets carve the protoplanetary disk, creating a “hole” in the innermost part of the disk, and preventing mm-sized dust particles (like grains of sand on a beach) from continuing their journey towards the central star. At the same time, dust particles in the outermost parts of the disk (the farthest from the star) are attracted by the gravitational force of the star.

    The combination of both effects should create dust structures in the form of a ring in disks that host recently formed giant planets on the inside.

    “The sharp image from ALMA shows a ring around the young star. And it is a surprisingly large ring, over three times the size of Neptune’s orbit (a radius of approximately 110 astronomical units (AU)” explains Héctor Cánovas.

    The image from ALMA only shows the ring, as the radio telescope detects the cold dust particles that make it up, and not the planets and the star, as these are primarily made up of hot gas.

    “Based on the current paradigm of planet-disk interactions, only giant planets orbiting the innermost parts of the disk can explain the presence of a ring with such a large radius,” indicates Antonio Hales, ALMA astronomer and member of the research team.

    The accumulation of dust particles in a narrow annular structure, as is the case with Sz91, can favor the formation of more planets, because the high density of dust particles in the ring would provide the ideal conditions for the dust particles to agglutinate and grow in size until they form small planetary nuclei.

    “The results of this investigation show that Sz91 is a highly important protoplanetary disk for the study of planetary formation, planet-disk interactions, and the evolution of these disks around stars of lower mass, as Sz91 shows evidence of all these processes simultaneously,” concludes Matthias Schreiber, coauthor of the study.

    Additional information

    This investigation was presented in an article entitled A ring-like concentration of mm-sized particles in Sz 91, written by Héctor Cánovas and collaborators, which will soon be published in the specialized journal Monthly Notices of the Royal Astronomical Society (MNRAS).

    The research team is made up of Héctor Cánovas, Claudio Cáceres, Matthias Schreiber, Adam Hardy (all from Universidad de Valparaíso and from the Millennium ALMA Disk Nucleus (MAD), Chile), Lucas Cieza (Universidad Diego Portales and MAD, Chile), Francois Ménard (Universidad de Chile) and Antonio Hales (JAO-ALMA, Chile).

    Link

    A ring-like concentration of mm-sized particles in Sz 91

    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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    ESO 50

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  • richardmitnick 12:36 pm on January 26, 2016 Permalink | Reply
    Tags: , , , Long Wavelength Array, Radio Astronomy, Radio Transmissions of Shooting Stars   

    From Eos: “Decoding the Radio Transmissions of Shooting Stars” 

    Eos news bloc

    Eos

    1.26.16
    Mark Zastrow

    For millennia, humans have cast their gaze to the cosmos and watched in awe as meteors streak across the night sky, leaving behind glowing trails of ionized air and superheated fragments of debris. But in 2014, scientists discovered that the brightest fireball meteors don’t just emit heat and light as they fall through the atmosphere—they also emit radio waves.

    This discovery came as something of a surprise. Meteors have been known to emit short radio bursts at very low frequencies and also some electromagnetic pulses lasting less than a microsecond. But these high-frequency radio emissions last anywhere from 10 seconds to well over 3 minutes, and their origin has stumped scientists.

    Now the team has reported more detailed observations that they think may get them closer to the answer. Obenberger et al. used an array of radio telescopes [LWA] in the New Mexico desert to tune into these brief broadcasts, intercepting emissions from two fireball meteors in October 2014.

    Long Wavelength Array Station 1
    Long Wavelength Array Station 1

    They measured their signal strength across a swath of the high-frequency radio spectrum and found that it was strongest below 25 megahertz, with a mostly smooth falloff toward higher frequencies.

    The measurements have allowed the team to discount one possibility: that it could be reflected radio signals, from either the ground or celestial objects like the galactic core. This was a reasonable guess—radio operators can bounce transmissions off of meteor ionization trails to boost signal range, a technique used by militaries, researchers, and ham radio operators alike. But if that were the case here, as winds blow the trail across the sky, the signal strength across the spectrum should spike and fall out sporadically. In addition, human-made signals are typically very narrow—in contrast, these new data show an extremely broadband signal that is relatively smooth over time.

    Using these measurements, the team thinks that the meteor itself is generating the radio waves. As the meteoroid streaks through the mesosphere, shedding mass and ionizing the air, it may create high-velocity electrons in its wake. These energetic electrons could strike the surrounding plasma like wind on an ocean—whipping up plasma waves that would generate the radio emissions the team detected.

    During one of the fireballs, the team also picked up bursts of polarized light that appeared for roughly 10 seconds, their frequency decreasing over time. The rate at which the pulse frequency decreases over time resembles what the scientists would expect for an expanding plasma, which they interpret as further evidence that the radio waves originate from the meteor trail. The pulses could be the result of clumps of dense, hot plasma that then expand into a broader trail.

    The team expects to get even more detailed data in the near future; the facility they used, the Long Wavelength Array, is currently expanding to include a second station about 75 kilometers away. When that comes online, the team will be able to precisely triangulate the trajectories of the meteors and take detailed images to measure the trail’s expansion. (Journal of Geophysical Research: Space Physics, doi:10.1002/2015JA021229, 2015)

    See the full article here .

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    Eos is the leading source for trustworthy news and perspectives about the Earth and space sciences and their impact. Its namesake is Eos, the Greek goddess of the dawn, who represents the light shed on understanding our planet and its environment in space by the Earth and space sciences.

     
  • richardmitnick 5:35 pm on January 21, 2016 Permalink | Reply
    Tags: , , , , Radio Astronomy,   

    From GIZMODO: “How Should We Look For Aliens?” 

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    GIZMODO

    1.20.16
    Mika McKinnon

    The search for extraterrestrial life is the ultimate hybrid of creativity and science, the quest to discover something we can’t even describe yet. Jill Tarter embodies that creativity in her work with the SETI Institute, and is the subject of a special video released today.

    WeTransfer’s Creative Class is an online series highlighting creative people doing cool things in the world. This season, the series features SETI Institute astronomer Jill Tarter, the real-life inspiration for Carl Sagan’s Dr. Ellie Arroway in Contact.

    Tarter chatted with Gizmodo about the role of creativity in the search for intelligent aliens, exclaiming, “You have to try to think creative[ly]about how do you discover what you really can’t imagine!”

    SETI Jill Tarter
    Jill Tarter, real-life alien-hunting astronomer

    “I like to say we’re looking for photons, but maybe it’s zeta rays that the advanced technologies of the universe are using to communicate,” Tarter offered as an analogy. “I don’t know what a zeta ray is because we haven’t invented it yet. We don’t understand that physics yet. Maybe that’s in our future.”

    We haven’t found aliens yet, so we need to keep expanding the very way that we search. “How do you look at the universe in new ways that will allow you to find things you that you didn’t imagine?” Tarter said. “[Astronomer Martin Harwit] made this case for essentially venture investing in the astronomical sciences because every time you open up a new observation space, we found something we didn’t expect!”

    Astronomy is full of such examples. Tarter recounts the iconic discovery of pulsars that started in 1965-66, when a team of graduate students built a new type of radio telescope:

    Jocelyn Bell and her colleagues spent the summer nailing up kilometers of wire and fence posts to make a low-frequency detector. They made it for a very scientific goal, but yet when Jocelyn was looking at the data, she found these little bits scruff. She was curious enough and systematic enough to follow up on them.

    Suddenly, wow! There are radio beacons out there more precise than any clock we’ve built. There are entire stars, neutron stars, that are spinning around several times a second. Unbelievable! They found it because they had a new tool. They had a different way of looking at the universe.

    This happens again and again and again. Every time we invent a new tool, discoveries follow. “I think being creative, building new ways to look at the universe, can lead to amazing results.” Tarter said. “You don’t do that if you think, ‘Well, I’m going to do today what I did yesterday.’”

    Our conversation with Tarter was so interesting and so long that we couldn’t transcribe it all in just one night. Instead, check out her Creative Class special here.

    See the full article here .

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    “We come from the future.”

    GIZMOGO pictorial

     
  • richardmitnick 3:28 pm on January 21, 2016 Permalink | Reply
    Tags: , , , Dark 'noodles' may lurk in the Milky Way, Radio Astronomy   

    From CSIRO: “Dark ‘noodles’ may lurk in the Milky Way” 

    CSIRO bloc

    Commonwealth Scientific and Industrial Research Organisation

    22 January 2016

    Mr Eamonn Bermingham
    Communication Advisor · Communications
    Phone: +61 7 3833 5601 +61 477 317 235 (Mobile)
    Email: Eamonn.Bermingham@csiro.au

    Dr Keith Bannister
    Principal Research Engineer · Astronomy and Space Science
    Phone: +61 2 9372 4295
    Email: Keith.Bannister@csiro.au

    Invisible structures shaped like noodles, lasagne sheets or hazelnuts could be floating around in our Galaxy radically challenging our understanding of gas conditions in the Milky Way.

    CSIRO Australia Compact Array
    CSIRO’s Compact Array

    CSIRO astronomer and first author of a paper released in Science Dr Keith Bannister said the structures appear to be ‘lumps’ in the thin gas that lies between the stars in our Galaxy.

    “They could radically change ideas about this interstellar gas, which is the Galaxy’s star recycling depot, housing material from old stars that will be refashioned into new ones,” Dr Bannister said.

    Dr Bannister and his colleagues described breakthrough observations of one of these ‘lumps’ that have allowed them to make the first estimate of its shape.

    The observations were made possible by an innovative new technique the scientists employed using CSIRO’s Compact Array telescope in eastern Australia.

    Astronomers got the first hints of the mysterious objects 30 years ago when they saw radio waves from a bright, distant galaxy called a quasar varying wildly in strength.

    They figured out this behaviour was the work of our Galaxy’s invisible ‘atmosphere’, a thin gas of electrically charged particles which fills the space between the stars.

    “Lumps in this gas work like lenses, focusing and defocusing the radio waves, making them appear to strengthen and weaken over a period of days, weeks or months,” Dr Bannister said.

    These episodes were so hard to find that researchers had given up looking for them.

    But Dr Bannister and his colleagues realised they could do it with CSIRO’s Compact Array.

    Pointing the telescope at a quasar called PKS 1939–315 in the constellation of Sagittarius, they saw a lensing event that went on for a year.

    Astronomers think the lenses are about the size of the Earth’s orbit around the Sun and lie approximately 3000 light-years away – 1000 times further than the nearest star, Proxima Centauri.

    Until now they knew nothing about their shape, however, the team has shown this lens could not be a solid lump or shaped like a bent sheet.

    “We could be looking at a flat sheet, edge on,” CSIRO team member Dr Cormac Reynolds said.

    “Or we might be looking down the barrel of a hollow cylinder like a noodle, or at a spherical shell like a hazelnut.”

    Getting more observations will “definitely sort out the geometry,” he said.

    While the lensing event went on, Dr Bannister’s team observed it with other radio and optical telescopes (NRAO/Very Long Baseline Array [VLBA], Australian Long Baseline Array, Gemini,CTIO/SMARTS)

    NRAO VLBA
    VLBA

    Australian Long Baseline Array
    Australian Long Baseline Array map

    Gemini South telescope
    GEMINI

    NOAO SMARTS
    CTIO/SMARTS

    The optical light from the quasar didn’t vary while the radio lensing was taking place. This is important, Dr Bannister said, because it means earlier optical surveys that looked for dark lumps in space couldn’t have found the one his team has detected.

    So what can these lenses be? One suggestion is cold clouds of gas that stay pulled together by the force of their own gravity. That model, worked through in detail, implies the clouds must make up a substantial fraction of the mass of our Galaxy.

    Nobody knows how the invisible lenses could form. “But these structures are real, and our observations are a big step forward in determining their size and shape,” Dr Bannister said.

    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 7:06 am on January 19, 2016 Permalink | Reply
    Tags: , , Molonglo Observatory Synthesis Telescope (MOST), Radio Astronomy   

    From Swinburne: “The Universe, one millisecond at a time” 

    Swinburne U bloc

    Swinburne University

    15 January 2016
    Jessica Hales
    +61 3 9214 8077
    jhales@swin.edu.au

    Molonglo Observatory Synthesis Telescope (MOST)
    The Molonglo Observatory Synthesis Telescope (MOST) is the largest radio telescope in the Southern Hemisphere

    About thirty kilometres east of the Australian capital Canberra stands a telescope that will soon capture images of the cosmos’s most mysterious phenomena. The Molonglo Observatory Synthesis Telescope (MOST), nestled in the Molonglo Valley, is the largest radio telescope in the Southern Hemisphere and has been scanning the skies for nearly half a century.

    Now, the Australian astronomy community have ambitious plans to use this telescope to understand the ‘transient’ Universe, short-lived phenomena that can only be detected through frequent, regular radiofrequency surveys.

    But before this can happen, MOST needed to be brought into the 21st Century. After operating for fifty years — a lifetime for any piece of technology, especially one as complex and sensitive as a giant radio telescope — it desperately needed an upgrade, especially to its digital technology.

    While its basic structure would remain the same, the revamp to its operational infrastructure would make it capable of churning through the masses of data generated by these surveys.

    In 2012, the UTMOST project was conceived to achieve this goal when the telescope’s operators, The University of Sydney, joined forces with Swinburne University of Technology, the CSIRO, Australian National University and Massachusetts Institute of Technology. Matthew Bailes, an Australian Laureate Fellow at the Swinburne Centre for Astrophysics and Supercomputing, took on the task of leading the upgrade of the telescope’s ageing processing system.

    1,320 gigabytes a minute

    When it was built in the 1960s, the Molonglo telescope discovered some of the most spectacular objects in our cosmos, such as the collapsed cores of once-massive stars, known as pulsars.

    Pulsars can be as small as 20 kilometres in diameter, and can spin at up to 700 times each second. Their distinctly pulsatile radiofrequency signature results from the acceleration of particles in their super-strong magnetic fields as they spin.

    “It’s fun when you find a pulsar that is spinning 700 times a second; that’s faster than a kitchen blender and yet it’s a star,” says Bailes.

    Precisely measuring the pulse rate of these celestial objects has revealed new insights into how gravity distorts the fabric of space-time.

    MOST’s long structure was built to overcome the design limitations imposed on parabolic dish telescopes, which can only get so big before they topple over. The telescope has two 800-metre-long half-cylinders stretching east to west. Along its two arms sit 7,744 individual radio antennae that combine their signals to create a concentrated radiofrequency beam.

    The upgrade kept this design, but called for a radical overhaul under the hood, installing new signal-processing computers that could sift through 22 gigabytes of data every second, or 1,320 gigabytes per minute.

    Early on, Bailes realised the upgrade couldn’t rely on existing analogue systems to combine the signals to form an image — it needed a system that could digitally combine all the signals together.

    “I realised that some of the technology we’d developed here at Swinburne could be adapted to do that,” says Bailes.

    Anne Green, a professor of astrophysics at the Sydney Institute for Astronomy, in The University of Sydney, says one of the major achievements of Bailes and his team has been to write new software for the telescope to improve data acquisition and signal processing. The upgrades will allow astronomers to observe a large area of the sky 1,000 times a second.

    “The powerful supercomputer that Bailes and Swinburne have provided makes this an exceptional telescope for exploring the transient sky with fast and flexible cadence,” says Green.

    In the astronomy world, Bailes’ supercomputer experience is highly sought after. In July 2015, he joined an international team awarded US$100 million to search for intelligent life elsewhere in the Universe. Bailes’ Australian team will design a new supercomputer at the Parkes telescope to analyse distant radio signals picked up by the search, which will be 50 times more sensitive than previous searches and cover ten times more sky.

    CSIRO Parkes Observatory
    Parkes Radio Telescope

    The project, administered by the Breakthrough Prize Foundation, will scan the skies for signals of life as well as other naturally occurring astrophysical phenomena.

    1,000 snapshots a second

    After a five-year hiatus, MOST recently began scanning the skies again. One of its first priorities will be to observe fast radio bursts — very bright, millisecond-long flashes of radio energy first observed just ten years ago.

    Only around fifteen of these events have ever been observed by astronomers, some by Bailes and colleagues at Swinburne University. They appear to be happening outside our Galaxy, but no one really knows what causes them.

    “There are more theories than there are bursts,” Bailes says. “Some people think that they occur when two neutron stars collide, others think that neutron stars become unstable and collapse into a black hole and they give off little bursts of radio emission when they do it.”

    Temp 2
    PSR B1509-58
    When an image from NASA’s Chandra X-ray Observatory of PSR B1509-58 — a spinning neutron star surrounded by a cloud of energetic particles –was released in 2009, it quickly gained attention because many saw a hand-like structure in the X-ray emission. In a new image of the system, X-rays from Chandra in gold are seen along with infrared data from NASA’s Wide-field Infrared Survey Explorer (WISE) telescope in red, green and blue. Pareidolia may strike again as some people report seeing a shape of a face in

    WISE’s infrared data. What do you see?

    NASA’s Nuclear Spectroscopic Telescope Array, or NuSTAR, also took a picture of the neutron star nebula in 2014, using higher-energy X-rays than Chandra.

    NASA Chandra Telescope
    NASA/Chandra

    NASA Wise Telescope
    NASA/WISE

    NASA NuSTAR
    NASA/NuSTAR

    PSR B1509-58 is about 17,000 light-years from Earth.
    JPL, a division of the California Institute of Technology in Pasadena, manages the WISE mission for NASA. NASA’s Marshall Space Flight Center in Huntsville, Alabama, manages the Chandra program for. The Smithsonian Astrophysical Observatory in Cambridge, Massachusetts, controls Chandra’s science and flight operations.
    Date 22 October 2014, 06:18:26
    NASA/CXC/SAO (X-Ray); NASA/JPL-Caltech (Infrared)

    Other theories suggest that they arise when black holes and neutron stars merge, or as an early warning signal of an impending supernova. There is even the suggestion that these bursts might have something to do with the atmosphere of a star that makes them appear further away than they really are.

    Once every few weeks

    The upgraded Molonglo telescope isn’t yet fully operational, and is currently running at only a quarter of its efficiency. But Bailes is already excited about what might come when it reaches its full potential.

    “The detection rate is a strong function of efficiency so we haven’t been running long enough to find a fast radio burst, but we’re hoping that soon we’ll be finding one every few weeks.”

    The Molonglo telescope is also continuing its long tradition of contributing to the field of pulsar study. Bailes spends much of his time studying these spinning neutron stars as a kind of hot-house for strange gravitational behaviour.

    “Neutron stars are very tiny so they can get in very close proximity to each other, which means that they travel very quickly around each other and they allow us to test gravity in ways that we can’t normally do,” Bailes says.

    These rapidly waltzing pairs might even answer a puzzle left by [Albert] Einstein. The great physicist predicted the existence of a peculiar type of gravitational ‘radiation’ called gravitational waves — but no one has seen one yet. In theory, pulsar pairs should emit these waves. While astronomers can’t detect the waves themselves, they can detect the changes to the orbits of these spinning pairs as tiny amounts of energy carried off by the gravitational waves.

    “These waves are mysterious and difficult to detect but they actually cause the orbit of the neutron star to shrink by one centimetre per day, which might not sound like much, but using the upgraded telescope we can measure the position of neutron stars so accurately that we can even begin to see that effect.”

    Given the fundamental importance of this work, there’s little doubt it will be time well spent.

    Sharing data

    Measuring a one-centimetre change in orbit from halfway across the Galaxy, or capturing a millisecond-long burst of radiofrequency energy somewhere in the Universe, requires extraordinary technology that is only found at very few locations around the world.

    In recognition of UTMOST’s unique capabilities, the collaboration has elected to make all the data generated by the Molonglo telescope available instantly to researchers anywhere in the world, which represents a big shift in the way astronomers communicate with each other.

    “Usually what you do is you build a telescope and you keep all the data secret and you do a grand magic reveal at the end,” Bailes says.

    “But with these fast radio bursts, if we did that, by the time we gave people the information it would be worthless because the thing would have faded away so we decided we’d give away any event immediately.”

    See the full article here .

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  • richardmitnick 5:56 pm on January 11, 2016 Permalink | Reply
    Tags: , , Radio Astronomy, Radio galaxies,   

    From U Oxford: “Exploring spiral-host radio galaxies” 

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    Oxford University

    OUP blog bloc

    Temp 1
    Hercules. A radio galaxy hosted in a massive elliptical galaxy. Radio emission, overplotted on the optical image, is shown in pink highlighting large jet-lobe structure. A Milky Way-sized spiral galaxy is marked by white ellipse. Image adapted from a Hubble Heritage Release. Credit: NASA, ESA, S. Baum and C. O’Dea (RIT), R. Perley and W. Cotton (NRAO/AUI/NSF), and the Hubble Heritage Team (STScI/AURA).

    January 9th 2016
    Veeresh Singh

    Few know exactly what radio galaxies are, much less what factors influence their formation. Even so, new discoveries have brought these astronomical structures into the public eye, and researchers continue to investigate the mysterious conditions of their existence. Below, Veeresh Singh addresses the substance and implications of such discoveries, further elaborating on his research paper, Discovery of rare double-lobe radio galaxies hosted in spiral galaxies, recently published in Monthly Notices of Royal Astronomical Society.

    What are radio galaxies?

    A galaxy is a gigantic system possessing billions of stars, vast amounts of gas, dust, and dark matter held together by gravitational attraction. The typical size of galaxies can be anywhere from a few tens-of-thousands to a few hundreds-of-thousands of light-years. Our own solar system is part of a galaxy named the “Milky Way.” Observations made from telescopes have shown that our universe is full of billions of galaxies that are of different shapes (e.g., spiral, spheroidal, elliptical and irregular).

    Studies on the motion of stars, gas, and dust close to the core of galaxies reveal that almost all galaxies host Super Massive Black Holes(SMBHs), which are millions to billions of times the mass of our Sun in their centres. In simple words, black holes are gravitationally collapsed systems in which gravity is so strong that even light cannot escape from the surface of their sphere of influence. Whenever matter is available in the vicinity of SMBHs, they accrete matter via gravitational pull and also eject a fraction of accreted matter—through outflowing bipolar collimated jets formed via magneto-hydro-dynamical processes.

    Galaxies having accreting SMBH are called “active galaxies.” Some of these active galaxies exhibit radio-emitting overflowing jets extending well beyond the size of host galaxies’ stellar distribution. These active galaxies are called “radio galaxies.” As the name itself suggests, radio galaxies are powerful emitters of radio emissions and show radio morphology that consists of a core producing a pair of bipolar collimated jets terminating in two lobes. The radio core coincides with the centre of the host galaxy seen in optical light but the jet-lobe extends well-beyond the host galaxy and entrenches into the empty space between galaxies, i.e. “intergalactic region.” Radio galaxies are one of the largest structures in the Universe and the total end-to-end radio size can range from thousands to millions of light years.

    What is the shape of hosts of radio galaxies?

    Traditionally, radio galaxies are found to be hosted in massive, gas-poor elliptical galaxies characterised by feeble star formation rates. It is believed that the relativistic jets emanating from the accreting SMBHs at their centres can easily plough through the rarer InterStellar Medium (ISM) of elliptical galaxies and reach scales of up to millions of light years.

    How common are spiral-host radio galaxies?

    Unlike conventional radio galaxies, which are almost always found in elliptical galaxies, we have discovered four radio galaxies (named in astronomical parlance as J0836+0532, J1159+5820, J1352+3126, and J1649+2635) that are found to be hosted in spiral galaxies. These extremely rare and enigmatic galaxies were found in a systematic search that combined a whopping 187,000 optical images of spiral galaxies from the Sloan Digital Sky Survey (SDSS) DR7 with the radio-emitting sources from two radio-surveys viz. ‘Faint Images of the Radio Sky at Twenty-cm (FIRST)’ and ‘NRAO VLA Sky Survey (NVSS)’ both carried out with the Very Large Array (VLA) radio telescope in the United States.

    SDSS Telescope
    SDSS telescope at Apache Point, NM, USA

    NRAO VLA
    NRAO/VLA

    This is the first attempt to carry out an extensive systematic search to find spiral-host radio galaxies using largest existing sky surveys. Before this work, only four examples of spiral-host radio galaxies were known and three of these were discovered serendipitously.

    What causes spiral galaxies to become radio-loud?

    Understanding the formation of these newly discovered spiral-host radio galaxies is a challenge in the present theoretical model. Using current available data on these sources it is speculated that the formation of spiral-host double-lobe radio galaxies can be attributed to more than one factor, such as the occurrence of strong interactions or mergers with other galaxies, and the presence of an unusually massive SMBH, while keeping the spiral structures intact. Notably, all these galaxies contain an SMBH at their centre with a mass of approximately a billion times that of the Sun.

    2
    J083+0532, a spiral galaxy with million-light-years large radio emitting jet-lobe structure. Upper panel shows contours of radio emission overplotted on the optical image from Sloane Digital Sky Survey (SDSS). Lower left panel represents the false colour radio image while lower right panel shows SDSS optical image. Image used with permission.

    Since only one among four was found in a cluster environment, it implies that the large scale environment is not the prime reason for triggering radio emission. Mergers or interactions could be more likely. In fact, two galaxies—J1159+5820 and J1352+3126—in this study show evidence of mergers. However, another two galaxies—J0836+0532 and J1649+2635—are face-on spirals and do not show any detectable signature of disturbance caused by a recent merger with another galaxy.

    How are galaxies currently being studied?

    In order to attain a better understanding of the formation of these galaxies, the research team is observing these galaxies at different frequencies. The team has already acquired low frequency radio observations with the Giant Metrewave Radio Telescope (GMRT) in India.

    Giant Metrewave Radio Telescope
    GMRT

    The multi-frequency radio observations will enable the study of the radio structures at different spatial scales and also in estimating the time elapsed since the radio emitting jets were ejected from the centre of each galaxy.

    What does the discovery of spiral-host radio galaxies mean to upcoming surveys?

    The discovery of these spiral-host radio galaxies can be considered as a test bed to find rare populations of spiral-host double-lobe radio galaxies in the distant universe using more sensitive surveys from upcoming facilities such as the Large Synoptic Survey Telescope (LSST) and the Square Kilometre Array (SKA).

    LSST Exterior
    LSST Interior
    LSST Camera
    LSST, the building which will house it, and the camera being built at SLAC

    SKA ASKAP telescope

    SKA Murchison Widefield Array
    From SKA, ASKAP and part of the Murchison Wide Field Array

    See the full article here.

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    Stem Education Coalition

    U Oxford campus

    Oxford is a collegiate university, consisting of the central University and colleges. The central University is composed of academic departments and research centres, administrative departments, libraries and museums. The 38 colleges are self-governing and financially independent institutions, which are related to the central University in a federal system. There are also six permanent private halls, which were founded by different Christian denominations and which still retain their Christian character.

    The different roles of the colleges and the University have evolved over time.

     
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