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  • richardmitnick 11:22 am on September 29, 2016 Permalink | Reply
    Tags: Analysing galaxy evolution in EAGLE, Angular momentum is a fundamental property of galaxies, , ,   

    From CAASTRO: “EAGLE simulation shows gain & loss of galaxies’ angular momentum” 

    CAASTRO bloc

    CAASTRO ARC Centre of Excellence for All Sky Astrophysics

    29 September 2016
    No writer credit

    Angular momentum is a fundamental property of galaxies, together with mass and energy. It is crucial to many scaling relations, for example the relation between a galaxy’s luminosity and its rotational velocity and size. Galaxy formation theory postulates that the amount of angular momentum in spiral galaxies can be obtained by assuming that they formed in dark matter halos through conservation of angular momentum. Elliptical galaxies though, which have much lower spins, need to lose more than 90% of the angular momentum they were formed with. Galaxy mergers are the main scenario invoked to explain such a major loss.

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    In a new publication, CAASTRO member Dr Claudia Lagos (ICRAR-UWA) and colleagues analysed the evolution of the angular momentum of galaxies in the EAGLE hydrodynamical simulations. EAGLE is a state-of-the-art simulation that has a unique compromise between the resolution required to study the structural properties of galaxies (spatial resolution of 700 pc) and the simulated cosmological volume (100 Mpc box side length). This allows for the study of about 13,000 galaxies in the simulation-equivalent of the local Universe. EAGLE is unique in its accurate reconstruction of galaxy properties across multiple research studies, predicting galaxies of roughly the right sizes, morphologies, colours, gas contents and star formation throughout cosmic time.

    This new study has found a correlation between the galaxies’ specific angular momentum (i.e. angular momentum as function of mass) and their stellar mass – in excellent agreement with observations and with the positions of galaxies as they correlate with gas content.

    Analysing galaxy evolution in EAGLE paints a picture that is more complex than what theory predicted: galaxies that have high specific angular momentum now formed most of their stars during the second half of the age of the Universe, from gas that was falling into their halos with high specific angular momentum. In contrast, galaxies that have low specific angular momentum now formed most of their stars during the first half of the age of the Universe, from material that had much lower specific angular momentum compared to the infalling gas later. The researchers conclude that the simple picture of two alternative scenarios – conservation of specific angular momentum or mergers that spin-down galaxies – does not capture what EAGLE has revealed to happen. How quickly a galaxy spins appears to depend on the individual star formation history with a contribution from the merger history.

    Publication details:
    Claudia Lagos et al. in the Monthly Notices of the Royal Astronomical Society (2016): Angular momentum evolution of galaxies in EAGLE

    See the full article here .

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    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 is a collaboration of The University of Sydney, The Australian National University, The University of Melbourne, Swinburne University of Technology, The University of Queensland, The University of Western Australia and Curtin University, the latter two participating together as the International Centre for Radio Astronomy Research (ICRAR). CAASTRO is funded under the Australian Research Council (ARC) Centre of Excellence program, with additional funding from the seven participating universities and from the NSW State Government’s Science Leveraging Fund.

     
  • richardmitnick 10:46 am on September 29, 2016 Permalink | Reply
    Tags: , , , , New Castle Herald,   

    From CSIRO via New Castle Herald: Women in STEM: “University of Newcastle graduate Karlie Noon thanks Wollotuka Institute” 

    CSIRO bloc

    Commonwealth Scientific and Industrial Research Organisation

    1

    New Castle Herald

    26 Sep 2016
    Helen Gregory

    1
    Karlie wants to inspire the next generation of young innovators.

    KARLIE Noon will become the first indigenous person in the state to attain a double degree in science and mathematics when she pulls on her academic gown for her University of Newcastle (UON) graduation this week.

    Ms Noon, a 26-year-old Kamilaroi woman from Tamworth, will be one of more than 1000 students who will graduate at ceremonies at the Callaghan campus on Thursday and Friday.

    “It’s hard to describe the impact finishing university has had back home,” Ms Noon said.

    “It has helped shift perceptions and raised the expectations for the people around me. My sister has since enrolled in a Bachelor of Nursing at UON after entering through the indigenous enabling program Yapug – and my cousin is also talking to me about going to university and studying science.”

    UON reached a milestone 1000 indigenous enrolments this year, which is equivalent to 3.5 per cent of its student population and the largest number at any Australian university.

    Ms Noon missed most of primary school but an indigenous elder tutored her once a week in maths.

    She enrolled in a Bachelor of Arts, but became interested in physics and changed degrees. “It was really challenging coming into a first year maths degree with no background but I was so determined to do it,” she said. “The Wollotuka Institute really were my support network here for anything I needed.”

    Ms Noon now works for the CSIRO, but her love of learning is far from over.

    A chance meeting with Monash University cultural astronomer, Dr Duane Hamacher, has encouraged her to pursue postgraduate study in indigenous astronomy.

    “I had experienced indigenous astronomy from a cultural perspective, but studying it in a Western paradigm wasn’t something I knew existed,” she said. “There are a lot of similarities between indigenous knowledge and physics, which I plan to explore further.”

    Ms Noon has also set her sights on obtaining her PhD. “It is the epitome of academia and at the moment there are no indigenous people with a PhD in Physics.”

    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 10:32 am on September 29, 2016 Permalink | Reply
    Tags: , AU, , , Stawell gold mine in western Victoria, Stawell Underground Physics Laboratory (SUPL)   

    From ARC Center of Excellence for Particle Physics at the Terascale: “Digging for Dark Matter” 

    arc-centers-of-excellence-bloc

    ARC Centre of Excellence for Particle Physics at the Terascale

    Digging for Dark Matter

    A tiny Australian mining town might hold the key to solving one of the universe’s biggest mysteries – and to a local economic boom. What do scientists hope to find in a cave 1km underground?

    9.29.16
    Lisa Clausen

    The public lookout point for the Stawell gold mine in western Victoria is an unremarkable spot; a few faded information boards and pieces of old equipment, rusting among crooked gums beside the mine’s high perimeter fence.

    Beyond the wire, near the slurry-coloured mine machinery which roars into the chill air, a dirt road descends steadily, through a rocky cutting, into the mine’s black mouth. It’s noisy, muddy and industrious – much like any number of working mines on a weekday – but not the sort of place where you’d imagine science might finally answer one of the great questions of our universe.

    And yet it could be. For more than 40 years, the mystery of dark matter has defied the world’s best physicists. These invisible particles are thought to be everywhere – constantly passing through each of us and our planet. In fact, we can only observe five per cent of the whole universe; the rest is dark matter and dark energy.

    Scientists have found compelling indirect evidence of dark matter’s existence, called gravitational lensing – where dark matter bends the visible light we see coming from distant galaxies. Yet this “stuff”, thought to shape galaxies and be the universe’s missing mass, remains frustratingly elusive. Directly detecting dark matter will be one of the greatest prizes of modern physics.

    “Dark matter holds galaxies together,” says University of Melbourne particle physicist, Professor Elisabetta Barberio. “If we understand it, we will understand how the universe evolved from the Big Bang to now, and how it might continue to evolve.”

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    University of Melbourne particle physicist, Professor Elisabetta Barberio. Photo: Peter Casamento

    Barberio is the project leader of an ambitious experiment set to happen in Australia. Until now, efforts to find dark matter have all taken place in the northern hemisphere, with plenty of funding and facilities. Now, thanks to the Stawell Underground Physics Laboratory (SUPL), the southern hemisphere will join the global hunt.

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    Underground Physics

    Its SABRE dark matter experiment will happen 1km underground in a country town of just over 6,000 people, best known for gold, farming, and a famous annual footrace – the Stawell Gift.

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    Stawell’s 160 years of gold mining history have left a network of tunnels under its streets, and disused shafts which occasionally open up in people’s gardens. It’s very much a mining town, but faced disastrous news when, in late 2012, the mine’s then-owners came to town council warning of the mine’s potential closure. After all, at its peak the mine employed about 400 people, while hundreds of others in local businesses benefited from its success.

    A panel of councillors, council staff, locals and mine management was convened to brainstorm ideas for what might come next. The list of community proposals quickly grew: should they start growing mushrooms? Or open a subterranean hotel?

    That same year, three hours down the highway in Melbourne, a group of physicists was wondering where they could stage a dark matter detection experiment. Swinburne University of Technology astrophysicist Jeremy Mould wrote to several mines across the country, outlining the group’s unusual request for a spare underground cavern. One of those letters went to Stawell’s council.

    Probing the nature of the universe hadn’t been on Stawell’s short list – yet. But what physicists needed was an underground site deep enough and in the right sort of landscape to block out the highly radioactive cosmic rays which relentlessly pelt the Earth’s surface. To the experiment’s incredibly sensitive detector, these rays are like a raucous radio station. The best way to turn down the volume is to head underground.

    Stawell’s mine, in places dug almost 2km deep through dense volcanic basalt, looked promising. Because it’s a mine with ramp access, rather than a vertical shaft, people and equipment could be driven in. And because it was in operation, power, ventilation and internet access were already in place.

    Most importantly, initial background radiation readings inside the mine were encouragingly low. Talks with council began and, in 2014, 60 scientists from around the world arrived to inspect the proposed site of the southern hemisphere’s first underground physics lab.

    “The penny dropped then that there was really something in this,” says Northern Grampians Shire Mayor Murray Emerson.

    Now, with $3.5m from the Victorian and federal governments, construction is due to begin later this year. The rock above SUPL will be a radiation shield equivalent to 3km of water. Even so, maintaining the lowest radiation levels possible means a complex build.

    It means everything from concrete to rock bolts must be tested before it can be used. By May this year, 26 component samples from sources as widespread as Adelaide to Gladstone had been tested, but only two found suitable. Quarry materials such as sand and aggregate must travel by road or train for analysis at the Australian Nuclear Science and Technology Organisation in Sydney – air travel gives off too much radiation. Materials such as the special concrete spray coating for the rock walls will have to be mixed on-site in specific containers, and stored away from mine materials.

    “It’s certainly an unusual challenge,” says site project engineer Allan Ralph. “Things that you would do on the surface without thinking about them have a significant difficulty to them when they’re underground and forming part of a world-class physics laboratory.”

    See the full article here .

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    Stem Education Coalition

    The objectives for the ARC Centres of Excellence are to:

    undertake highly innovative and potentially transformational research that aims to achieve international standing in the fields of research envisaged and leads to a significant advancement of capabilities and knowledge
    link existing Australian research strengths and build critical mass with new capacity for interdisciplinary, collaborative approaches to address the most challenging and significant research problems
    develop relationships and build new networks with major national and international centres and research programs to help strengthen research, achieve global competitiveness and gain recognition for Australian research
    build Australia’s human capacity in a range of research areas by attracting and retaining, from within Australia and abroad, researchers of high international standing as well as the most promising research students
    provide high-quality postgraduate and postdoctoral training environments for the next generation of researchers
    offer Australian researchers opportunities to work on large-scale problems over long periods of time
    establish Centres that have an impact on the wider community through interaction with higher education institutes, governments, industry and the private and non-profit sector.

     
  • richardmitnick 10:08 am on September 29, 2016 Permalink | Reply
    Tags: Pan-STARRS 1, rans-Neptunian Objects (TNOs), Trojan Asteroids, UH Institute for Astronomy,   

    From UH Institute for Astronomy via Universe Today: “Five New Neptunian Trojans Discovered” 

    U Hawaii

    University of Hawaii

    U Hawaii 2.2 meter telescope, Mauna Kea, Hawaii, USA
    U Hawaii 2.2 meter telescope, Mauna Kea, Hawaii, USA

    IFA at Manua Kea

    1

    Universe Today

    23 Sept 2016
    Matt Williams

    The Solar System is filled with what are known as Trojan Asteroids – objects that share the orbit of a planet or larger moon. Whereas the best-known Trojans orbit with Jupiter (over 6000), there are also well-known Trojans orbiting within Saturn’s systems of moons, around Earth, Mars, Uranus, and even Neptune.

    Until recently, Neptune was thought to have 12 Trojans. But thanks to a new study by an international team of astronomers – led by Hsing-Wen Lin of the National Central University in Taiwan – five new Neptune Trojans (NTs) have been identified. In addition, the new discoveries raise some interesting questions about where Neptune’s Trojans may come from.

    For the sake of their study – titled The Pan-STARRS 1 Discoveries of Five New Neptune Trojans– the team relied on data obtained by the Panoramic Survey Telescope and Rapid Response System (Pan-STARRS). This wide-field imaging facility – which was founded by the University of Hawaii’s Institute for Astronomy – has spent the last decade searching the Solar System for asteroids, comets, and Centaurs.

    2
    The PS1 telescope at dawn, with the mountain of Mauna Kea visible in the distance. Credit: pan-starrs.ifa.hawaii.edu

    The team used data obtained by the PS-1 survey, which ran from 2010 to 2014 and utilized the first Pan-STARR telescope on Mount Haleakala, Hawaii. From this, they observed seven Trojan asteroids around Neptune, five of which were previously undiscovered. Four of the TNs were observed orbiting within Neptune’s L4 point, and one within its L5 point.

    The newly detected objects have sizes ranging from 100 to 200 kilometers in diameter, and in the case of the L4 Trojans, the team concluded from the stability of their orbits that they were likely primordial in origin. Meanwhile, the lone L5 Trojan was more unstable than the other four, which led them to hypothesize that it was a recent addition.

    As Professor Lin explained to Universe Today via email:

    “The 2 of the 4 currently known L5 Neptune Trojans, included the one L5 we found in this work, are dynamically unstable and should be temporary captured into Trojan cloud. On the other hand, the known L4 Neptune Trojans are all stable. Does that mean the L5 has higher faction of temporary captured Trojans? It could be, but we need more evidence.”

    3
    Animation showing the path of six of Neptune’s L4 trojans in a rotating frame with a period equal to Neptune’s orbital period.. Credit: Tony Dunn/Wikipedia Commons

    From this, said Lin, they derived two possible explanations:

    “The L4 “Trojan Cloud” is wide in orbital inclination space. If it is not as wide as we thought before, the two observational results are statistically possible to generate from the same intrinsic inclination distribution. The previous study suggested >11 degrees width of inclination, and most likely is ~20 degrees. Our study suggested that it should be 7 to 27 degrees, and the most likely is ~ 10 degrees.”

    “[Or], the previous surveys were used larger aperture telescopes and detected fainter NT than we found in PS1. If the fainter (smaller) NTs have wider inclination distribution than the larger ones, which means the smaller NTs are dynamically “hotter” than the larger NTs, the disagreement can be explained.”

    According to Lin, this difference is significant because the inclination distribution of NTs is related to their formation mechanism and environment. Those that have low orbital inclinations could have formed at Neptune’s Lagrange Points and eventually grew large enough to become Trojans asteroids.

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    Illustration of the Sun-Earth Lagrange Points. Credit: NASA

    On the other hand, wide inclinations would serve as an indication that the Trojans were captured into the Lagrange Points, most likely during Neptune’s planetary migration when it was still young. And as for those that have wide inclinations, the degree to which they are inclined could indicate how and where they would have been captured.

    “If the width is ~ 10 degrees,” he said, “the Trojans can be captured from a thin (dynamically cold) planetesimal disk. On the other hand, if the Trojan cloud is very wide (~ 20 degrees), they have to be captured from a thick (dynamically hot) disk. Therefore, the inclination distribution give us an idea of how early Solar system looks like.”

    In the meantime, Li and his research team hope to use the Pan-STARR facility to observe more NTs and hundreds of other Centaurs, Trans-Neptunian Objects (TNOs) and other distant Solar System objects. In time, they hope that further analysis of other Trojans will shed light on whether there truly are two families of Neptune Trojans.

    This was all made possible thanks to the PS1 survey. Unlike most of the deep surveys, which are only ale to observe small areas of the sky, the PS1 is able to monitor the whole visible sky in the Northern Hemisphere, and with considerable depth. Because of this, it is expected to help astronomers spot objects that could teach us a great deal about the history of the early Solar System.

    See the full article here .

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    System Overview

    The University of Hawai‘i System includes 10 campuses and dozens of educational, training and research centers across the Hawaiian Islands. As the public system of higher education in Hawai‘i, UH offers opportunities as unique and diverse as our Island home.

    The 10 UH campuses and educational centers on six Hawaiian Islands provide unique opportunities for both learning and recreation.

    UH is the State’s leading engine for economic growth and diversification, stimulating the local economy with jobs, research and skilled workers.

     
  • richardmitnick 9:50 am on September 29, 2016 Permalink | Reply
    Tags: Small modular nuclear reactors,   

    From The Guardian: “Mini-nuclear reactors could be operating in the UK by 2030 – report” 

    The Guardian Logo

    The Guardian

    29 September 2016

    Energy Technologies Institute argues small modular reactors capable of delivering clean power and heat could be in place by 2030 if the right policy framework is put in place, reports BusinessGreen.

    1
    Last year the government announced plans for a £250m competition to boost nuclear development, including plans to support commercial SMRs. Photograph: Fabrice Coffrini/AFP/Getty Images

    The first small modular nuclear reactors (SMRs) could be operating in the UK by 2030 with the right government support, according to a new report from the Energy Technologies Institute (ETI).

    The analysis, released today by the government and industry-backed energy research body, examined the steps needed to support the first SMR in the UK and concluded a credible schedule for implementation can be set out – as long as a policy framework is developed to reduce risks for SMR developers and increase investor confidence.

    Setting out a timeline of key steps that will be required to deliver SMR deployment, the ETI said the UK should clarify and raise awareness of regulatory standards and expectations in the next five years and set out a clear statement of intent in relation to SMR development in the UK by 2024, with the aim to achieve at least one final investment decision by 2025.

    Mike Middleton, nuclear strategy manager at the ETI and author of the report, said vendors, government and regulators must all work together in an integrated programme to ensure the first of a kind SMR is in operation by 2030.

    “Creating the right environment for increasing investor confidence is critical if this schedule is to be met; there will be a key role for government in the first five years of any such programme to deliver an SMR policy framework which progressively reduces investor risk,” he said in a statement.

    The study also suggests developers should consider using SMRs as Combined Heat and Power (CHP) plants rather than simply for power generation, arguing the small size and relatively easy siting of SMRs mean they could feed low carbon heat directly into cities using hot water pipelines.

    The ETI argues developers should consider deploying SMRs that are “CHP ready”, even in cases where there is not yet strong local demand for district heating systems. The report suggests the additional cost of making the reactors capable of delivering CHP is small, but future heat revenues could be significant if district heating networks materialise.

    The case for deploying SMRs capable of producing heat is further bolstered by the fact they will be built to a standard design in factories before being assembled on site, the report said, meaning that including ‘CHP ready’ standards in all designs would reduce downstream deployment costs as there would be no need to reconfigure factory processes to deliver CHP integrated reactors.

    “Firstly, these options can increase deployment opportunities which can further reduce unit cost; secondly it is not necessary to reassess the design or reconfigure the factory production process to deliver these options and again this reduces downstream deployment costs,” said Middleton.

    Last year the government announced plans for a £250m competition to boost nuclear development, including plans to support commercial SMRs. Phase one of the programme waslaunched in March this year, with the government calling on developers to come forward with proposals for pilot projects.

    Meanwhile, companies such as US nuclear developer NuScale Power – which aims for its first SMR to be in operation in the US by 2024 – have shown increasing interest in deploying SMR technology in the UK.

    However, the ETI report argued that despite government support and warm words from ministers there is currently no programme for UK SMR deployment or SMR-specific policies to encourage private sector development.

    While advocates of SMRs maintain they can safely bring down the cost of nuclear power and help to support an increasingly decentralised grid, critics argue there is still little evidence the technology will bring down costs where larger reactors have consistently failed to do so and fear they will come with inherent safety risks, which other low carbon sources of power could avoid.

    However, the ETI report identified several sites in the UK that it said had potential for early SMR deployment, including sites which could be suited for a first of a kind SMR plant.

    It may still be very early days for the embryonic SMR industry, but some experts are increasingly confident an exciting future awaits.

    See the full article here .

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  • richardmitnick 9:32 am on September 29, 2016 Permalink | Reply
    Tags: , , Room-Temp Superconductors Could Be Possible   

    From BNL: “Room-Temp Superconductors Could Be Possible” 

    Brookhaven Lab

    September 27, 2016
    Ariana Tantillo

    1
    This composite image offers a glimpse inside the custom system Brookhaven scientists used to create samples of materials that may pave the way for high-temperature superconductors. | Image courtesy of Brookhaven National Lab.

    SUPERCONDUCTORS ARE THE HOLY GRAIL OF ENERGY EFFICIENCY.

    These mind-boggling materials allow electric current to flow freely without resistance. But that generally only happens at temperatures within a few degrees of absolute zero (minus 459 degrees Fahrenheit), making them difficult to deploy today. However, if we’re able to harness the powers of superconductivity at room temperature, we could transform how energy is produced, stored, distributed and used around the globe.

    In a recent breakthrough, scientists at the Department of Energy’s Brookhaven National Laboratory got one step closer to understanding how to make that possible. The research, led by physicist Ivan Bozovic, involves a class of compounds called cuprates, which contain layers of copper and oxygen atoms.

    Under the right conditions — which, right now, include ultra-chilly temperatures — electrical current flows freely through these cuprate superconductors without encountering any “roadblocks” along the way. That means none of the electrical energy they’re carrying gets converted to heat. If you’ve ever rested your laptop on your lap, you’ve felt the heat lost by a non-superconducting material.

    Creating the right conditions for superconductivity in cuprates also involves adding other chemical elements such as strontium. Somehow, adding those atoms and chilling the material causes electrons — which normally repel one another — to pair up and effortlessly move together through the material. What makes cuprates so special is that they can achieve this “magical” state of matter at temperatures a hundred degrees or more above those required by standard superconductors. That makes them very promising for real-world, energy-saving applications.

    These materials wouldn’t require any cooling, so they’d be relatively easy and inexpensive to incorporate into our everyday lives. Picture power grids that never lose energy, more affordable mag-lev train systems, cheaper medical imaging machines like MRI scanners, and smaller yet powerful supercomputers.

    To figure out the mystery of “high-temperature” superconductivity in the cuprates, scientists need to understand how the electrons in these materials behave. Bozovic’s team has now solved part of the mystery by determining what exactly controls the temperature at which cuprates become superconducting.

    The standard theory of superconductivity says that this temperature is controlled by the strength of the electron-pairing interaction, but Bozovic’s team has discovered otherwise. After 10 years of preparing and analyzing more than 2,000 samples of a cuprate with varying amounts of strontium, they found that the number of electron pairs within a given area (say, per cubic centimeter), or the density of electron pairs, controls the superconducting transition temperature. In other words, it’s not the forces between objects that matter here, but the density of objects–in this case, electron pairs.

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    A bonding structure of copper and oxygen atoms on a plane within a cuprate. No image credit.

    The scientists arrived at this conclusion by measuring how far a magnetic field was able to get through each sample. This distance is directly related to the density of electron pairs, and the distance differs depending on the material’s properties. In superconductors, the magnetic field is mostly expelled; in metals, the magnetic field permeates. With too much strontium, the cuprate becomes more conductive because the number of mobile electrons increases. Yet the scientists found that as they added more strontium, the number of electron pairs decreased until absolutely no electrons paired up at all. At the same time, the superconducting transition temperature dropped toward zero. Bozovic and his team were quite surprised at this discovery that only a fraction of the electrons paired up, even though they all should have.

    Think of it like this: You’re in a dance hall, and at some point, you and the other people — who normally wouldn’t be caught arm-in-arm — begin to pair up and move in unison. Some newcomers arrive, and they too pair up and join the harmonious dance. But then something strange happens. No matter how many more people make their way to the dance floor, only a fraction of them pair, even though they are all free to do so. Eventually, nobody pairs up at all.

    Why do the dancers, or electrons, pair up in the first place? Answering that question is the next step toward unlocking the mechanism of high-temperature superconductivity in the cuprates — a mystery that’s been puzzling physicists for more than 30 years.

    See the full article here .

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    BNL Campus

    One of ten national laboratories overseen and primarily funded by the Office of Science of the U.S. Department of Energy (DOE), Brookhaven National Laboratory conducts research in the physical, biomedical, and environmental sciences, as well as in energy technologies and national security. Brookhaven Lab also builds and operates major scientific facilities available to university, industry and government researchers. The Laboratory’s almost 3,000 scientists, engineers, and support staff are joined each year by more than 5,000 visiting researchers from around the world.Brookhaven is operated and managed for DOE’s Office of Science by Brookhaven Science Associates, a limited-liability company founded by Stony Brook University, the largest academic user of Laboratory facilities, and Battelle, a nonprofit, applied science and technology organization.
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  • richardmitnick 9:17 am on September 29, 2016 Permalink | Reply
    Tags: , , , Orion Spur, Where is the Milky Way?   

    From New Scientist: “Our home spiral arm in the Milky Way is less wimpy than thought” 

    NewScientist

    New Scientist

    28 September 2016

    It’s tricky to map an entire galaxy when you live in one of its arms. But astronomers have made the clearest map yet of the Milky Way – and it turns out that the arm that hosts our solar system is even bigger than previously thought.

    The idea that the Milky Way is a spiral was first proposed more than 150 years ago, but we only started identifying its limbs in the 1950s. Details about the galaxy’s exact structure are still hotly debated, such as the number of arms, their length and the size of the bar of hot gas and dust that stretches across its middle.

    The star-filled arms are densely packed with gas and dust, where new stars are born. That dust can obscure stars we use to measure distances, complicating the mapping process.

    .
    Two of the arms, called Perseus and Scutum-Centaurus, are larger and filled with more stars, while the Sagittarius and Outer arms have fewer stars but just as much gas. The solar system has been thought to lie in a structure called the Orion Spur, or Local Arm, which is smaller than the nearby Perseus Arm.

    1
    Artist’s conception of the Milky Way galaxy as seen from far Galactic North (in Coma Berenices) by NASA/JPL-Caltech/R. Hurt annotated with arms (colour-coded according to Milky Way article) as well as distances from the Solar System and galactic longitude with corresponding constellation.

    Just as grand

    Now, Ye Xu and colleagues from the Purple Mountain Observatory in Nanjing, China, say the Local Arm is just as grand as the others.

    Purple Mountain Observatory
    Purple Mountain Observatory in Nanjing, China

    The team used the Very Long Baseline Array in New Mexico to make extremely accurate measurements of high-mass gas clouds in the arms, and used a star-measuring trigonometry trick called parallax to measure their distances.

    NRAO VLBA
    NRAO VLBA

    “Radio telescopes can ‘see’ through the galactic plane to massive star forming regions that trace spiral structure, while optical wavelengths will be hidden by dust,” Xe says. “Achieving a highly accurate parallax is not easy.”

    The new measurements suggest the Milky Way is not a grand design spiral with well-defined arms, but a spiral with many branches and subtle spurs.

    However, Xu and colleagues say the Orion Spur is not a spur at all, but more in line with the galaxy’s other spectacular arms. The team also discovered a spur connecting the Local and Sagittarius arms.

    “This lane has received little attention in the past because it does not correspond with any of the major spiral arm features of the inner galaxy,” the authors of the study write.

    Future measurements with other radio telescopes will shed more light on the galaxy’s shape. The European Space Agency’s Gaia spacecraft is in the midst of a mission to make a three-dimensional map of our galaxy, too.

    ESA/GAIA satellite
    ESA/GAIA satellite

    More measurements of the high-mass gas regions will help astronomers determine what our galaxy looks like, from the inside out.

    Journal reference: Science Advances, DOI: 10.1126/sciadv.1600878

    See the full article here .

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  • richardmitnick 7:31 am on September 29, 2016 Permalink | Reply
    Tags: , ALMA Catches Stellar Cocoon with Curious Chemistry, , , ,   

    From ALMA: “ALMA Catches Stellar Cocoon with Curious Chemistry” 

    ALMA Array

    ALMA

    29 September 2016
    Contacts

    Takashi Shimonishi
    Frontier Research Institute for Interdisciplinary Sciences
    Tohoku University, Sendai, Miyagi, Japan
    Email: shimonishi@astr.tohoku.ac.jp

    Masaaki Hiramatsu
    NAOJ Chile Observatory EPO officer
    Tel: +81 422 34 3630
    Email: hiramatsu.masaaki@nao.ac.jp

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

    Richard Hook
    Public Information Officer, ESO

    Garching bei München, Germany

    Tel: +49 89 3200 6655

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

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

    1

    A hot and dense mass of complex molecules, cocooning a newborn star, has been discovered by a Japanese team of astronomers using ALMA. This unique hot molecular core is the first of its kind to have been detected outside the Milky Way galaxy. It has a very different molecular composition from similar objects in our own galaxy — a tantalising hint that the chemistry taking place across the Universe could be much more diverse than expected.

    A team of Japanese researchers have used the power of the Atacama Large Millimeter/submillimeter Array (ALMA) to observe a massive star known as ST11 [1] in our neighbouring dwarf galaxy, the Large Magellanic Cloud (LMC). Emission from a number of molecular gases was detected. These indicated that the team had discovered a concentrated region of comparatively hot and dense molecular gas around the newly ignited star ST11. This was evidence that they had found something never before seen outside of the Milky Way — a hot molecular core [2].

    Takashi Shimonishi, an astronomer at Tohoku University, Japan, and the paper’s lead author enthused: “This is the first detection of an extragalactic hot molecular core, and it demonstrates the great capability of new generation telescopes to study astrochemical phenomena beyond the Milky Way.”

    The ALMA observations revealed that this newly discovered core in the LMC has a very different composition to similar objects found in the Milky Way. The most prominent chemical signatures in the LMC core include familiar molecules such as sulfur dioxide, nitric oxide, and formaldehyde — alongside the ubiquitous dust. But several organic compounds, including methanol (the simplest alcohol molecule), had remarkably low abundance in the newly detected hot molecular core. In contrast, cores in the Milky Way have been observed to contain a wide assortment of complex organic molecules, including methanol and ethanol.

    Takashi Shimonishi explains: “The observations suggest that the molecular compositions of materials that form stars and planets are much more diverse than we expected.”

    4
    Fig.2 Left: Distributions of molecular line emission from a hot molecular core in the Large Magellanic Cloud observed with ALMA. Emissions from dust, sulfur dioxide (SO2), nitric oxide (NO), and formaldehyde (H2CO) are shown as examples. Right: An infrared image of the surrounding star-forming region (based on the 8 micron data provided by the NASA/Spitzer Space Telescope). Credit: T. Shimonishi/Tohoku University, ALMA (ESO/NAOJ/NRAO)

    The LMC has a low abundance of elements other than hydrogen or helium [3]. The research team suggests that this very different galactic environment has affected the molecule-forming processes taking place surrounding the newborn star ST11. This could account for the observed differences in chemical compositions.

    It is not yet clear if the large, complex molecules detected in the Milky Way exist in hot molecular cores in other galaxies. Complex organic molecules are of very special interest because some are connected to prebiotic molecules formed in space. This newly discovered object in one of our nearest galactic neighbours is an excellent target to help astronomers address this issue. It also raises another question: how could the chemical diversity of galaxies affect the development of extragalactic life?

    Notes

    [1] ST11’s full name is 2MASS J05264658-6848469. This catchily-named young massive star is defined as a Young Stellar Object. Although it currently appears to be a single star, it is possible that it will prove to be a tight cluster of stars, or possibly a multiple star system. It was the target of the science team’s observations and their results led them to realise that ST11 is enveloped by a hot molecular core.

    [2] Hot molecular cores must be: (relatively) small, with a diameter of less than 0.3 light-years; have a density over a thousand billion (1012) molecules per cubic metre (far lower than the Earth’s atmosphere, but high for an interstellar environment); warm in temperature, at over –173 degrees Celsius. This makes them at least 80 degrees Celsius warmer than a standard molecular cloud, despite being of similar density. These hot cores form early on in the evolution of massive stars and they play a key role in the formation of complex chemicals in space.

    [3] The nuclear fusion reactions that take place when a star has stopped fusing hydrogen to helium generate heavier elements. These heavier elements get blasted into space when massive dying stars explode as supernovae. Therefore, as our Universe has aged, the abundance of heavier elements has increased. Thanks to its low abundance of heavier elements, the LMC provides insight into the chemical processes that were taking place in the earlier Universe.

    More information

    This research was presented in a paper published in the Astrophysical Journal on August 9, 2016, entitled The Detection of a Hot Molecular Core in the Large Magellanic Cloud with ALMA.

    The team is composed of Takashi Shimonishi (Frontier Research Institute for Interdisciplinary Sciences & Astronomical Institute, Tohoku University, Japan), Takashi Onaka (Department of Astronomy, The University of Tokyo, Japan), Akiko Kawamura (National Astronomical Observatory of Japan, Japan) and Yuri Aikawa (Center for Computational Sciences, The University of Tsukuba, Japan).

    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 3:54 pm on September 28, 2016 Permalink | Reply
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    From UCLA: “Research resolves a debate over ‘killer electrons’ in space” 

    UCLA bloc

    UCLA

    September 28, 2016
    Stuart Wolpert

    1
    A visualization of the Earth’s magnetic environment. Martin Rother/GFZ Research Centre for Geosciences.

    New findings by a UCLA-led international team of researchers answer a fundamental question about our space environment and will help scientists develop methods to protect valuable telecommunication and navigation satellites. The research is published today in the journal Nature Communications.

    Using measurements from the first U.S. satellite that traveled to space, Explorer 1 physicist James Van Allen discovered in 1958 that space is radioactive. The Earth is surrounded by two doughnut-shaped rings of highly charged particle radiation — an inner ring of high-energy electrons and positive ions and an outer ring of high-energy electrons — that are now known as Van Allen Radiation Belts. Flying close to the speed of light, the high-energy particles that populate the belts create a harsh environment for satellites and humans in space.

    In recent years, there has been much scientific interest in understanding the Van Allen belts. New technologies now require that telecommunication satellites spend a great deal of time in those belts and that GPS satellites operate in the heart of the belts. With the increasingly smaller size of space electronics has come greater vulnerability of satellites to space radiation, according to Yuri Shprits, a research geophysicist with Earth, Planetary and Space Sciences in the UCLA College and a member of the international team.

    The particles that are most dangerous to spacecraft are known as relativistic and ultra-relativistic electrons. The ultra-relativistic, or “killer electrons,” are especially hazardous and can penetrate the most protected and valuable satellites in space, Shprits said. While it is possible to protect the satellites from relativistic particles, shielding from ultra-relativistic particles is practically impossible, he added.

    Understanding the dynamics of these particles has been a major challenge for scientists since Van Allen discovered space radiation. Since the late 1960s, scientists have made many observations to try to understand the loss of electrons from the Van Allen belts.

    One of the proposed theories was that particles are scattered into the atmosphere by electromagnetic ion cyclotron waves. These waves are produced by the injection of ions that are heavier than electrons and carry a lot of energy. These waves can potentially scatter electrons into the atmosphere. Up until recently, that remained the most likely candidate for the loss of electrons.

    In 2006, Shprits and colleagues proposed another mechanism. They suggested that more than 99 percent of the particles suddenly were lost, as electrons diffused into interplanetary space, no longer trapped by the Earth’s magnetic field. The team conducted additional studies that provided more evidence for this mechanism.

    The scientists’ modeling of large numbers of electrons at relativistic energies seemed to favor this mechanism and did not require the scattering of electron by electromagnetic ion cyclotron waves. However, it remained unclear which mechanism operated or dominated during storms, and which mechanism explains the most dramatic dropouts of electrons in the space environment.

    The loss of particles is difficult to pinpoint. Both types of loss mechanisms are intensified during storms, making it difficult to distinguish one from the other.

    2
    An illustration of the structure of the Van Allen Radiation Belt after a storm. Copyright Ingo Michaelis. Background image courtesy of European Space Agency/NAS.

    Fortunately for the scientists, several factors combined to help them resolve the dispute. A January 2013 storm in the Van Allen belts allowed the researchers to use detectors to measure the particles’ distributions and direction. The most intense relativistic and ultra-relativistic electrons were discovered in different locations in the belts. And the ultra-relativistic particles were located deep inside the magnetosphere (and were not affected by the electron loss to the magnetopause, which is the boundary between the Earth’s magnetic field and the solar wind).

    The researchers’ detailed measurements — including particle speed, velocity direction and radial distributions — all showed that the waves were indeed scattering particles into the atmosphere but affected only ultra-relativistic electrons, not relativistic particles.

    “Our findings resolve a fundamental scientific question about our space environment and may help develop methods of cleaning up the radiation belts from harmful radiation and make the environment around the Earth friendlier for satellites,” Shprits said. He is principal investigator of an April mission in which a satellite containing a UCLA-built collection of instruments was launched from Vostochny, Siberia. That work is expected to provide scientists worldwide with measurements of radiation in space and advance space sciences for years to come.

    Other members of the team are scientists from UCLA (researchers Alexander Drozdov and Adam Kellerman, and postdoctoral scholar Hui Zhu); Germany’s GFZ Research Centre for Geosciences in Potsdam (Irina Zhelavskaya and Nikita Aseev, who were visiting scholars at UCLA for six months in 2015-16; Shprits holds a joint appointment here); Stanford University (Maria Spasojevic); University of Colorado, Boulder (Maria Usanova and Daniel Baker); Augsburg College in Minneapolis (Mark Engebretson); UC Berkeley (Oleksiy Agapitov, who also has an appointment at Ukraine’s University of Kyiv); Finland’s University of Oulu (Tero Raita); and the University of New Hampshire (Harlan Spence).

    Funding sources for the Nature Communications research included the University of California Office of the President, National Science Foundation, NASA and the Helmholtz Association Recruiting Imitative program.

    See the full article here .

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    UC LA Campus

    For nearly 100 years, UCLA has been a pioneer, persevering through impossibility, turning the futile into the attainable.

    We doubt the critics, reject the status quo and see opportunity in dissatisfaction. Our campus, faculty and students are driven by optimism. It is not naïve; it is essential. And it has fueled every accomplishment, allowing us to redefine what’s possible, time after time.

    This can-do perspective has brought us 12 Nobel Prizes, 12 Rhodes Scholarships, more NCAA titles than any university and more Olympic medals than most nations. Our faculty and alumni helped create the Internet and pioneered reverse osmosis. And more than 100 companies have been created based on technology developed at UCLA.

     
  • richardmitnick 3:41 pm on September 28, 2016 Permalink | Reply
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    From Frontier Fields: “Beyond the Frontier Fields: How JWST Will Push the Science to a New Frontier” 

    Frontier Fields
    Frontier Fields

    September 28, 2016
    bonniemeinke

    The Frontier Fields Project has been an ambitious campaign to see deep into our universe. Gravitational lensing, as used by the Frontier Fields Project, enables Hubble to see fainter and more-distant galaxies than would otherwise be possible. These images push to the very limits of how deeply Hubble can see out into space.

    NASA/ESA Hubble Telescope
    NASA/ESA Hubble Telescope

    Hubble, Spitzer, Chandra, and other observatories are doing cutting-edge science through the Frontier Fields Project, but there’s a challenge.

    NASA/Spitzer Telescope
    NASA/Spitzer Telescope

    NASA/Chandra Telescope
    NASA/Chandra Telescope

    Even though leveraging gravitational lensing has allowed astronomers to see objects that otherwise could not be detected with today’s telescopes, the technique still isn’t enough to see the most distant galaxies. As the universe expands, light gets stretched into longer and longer wavelengths, beyond the visible and near-infrared wavelengths Hubble can detect. To see the most distant galaxies, one needs a space telescope with Hubble’s keen resolution, but at infrared wavelengths.

    That infrared telescope is the James Webb Space Telescope, slated to launch in October 2018. It has a mirror 6.5 meters (21 feet) across, can observe wavelengths up to 10 times longer than Hubble can observe, and is the mission that will detect and study the first appearances of galaxies in the universe.

    1
    Figure 1: Webb will have a 6.5-meter-diameter primary mirror, which would give it a significant larger collecting area than the mirrors available on the current generation of space telescopes. Hubble’s mirror is a much smaller 2.4 meters in diameter, and its corresponding collecting area is 4.5 square meters, giving Webb around seven times more collecting area! Webb’s field of view is more than 15 times larger than the NICMOS near-infrared camera on Hubble. It also will have significantly better spatial resolution than is available with the infrared Spitzer Space Telescope. Credit: NASA. http://webbtelescope.org/gallery.

    Observations of the early universe are still incomplete. To build the full cosmological history of our universe, we need to see how the first stars and galaxies formed, and how those galaxies evolved into the grand structures we see today.

    Looking back in time to the first light in the universe:

    Astronomers use light to explore the universe, but there are pieces of our universe’s early history where there wasn’t much light. The era of the universe called the “Dark Ages” is as mysterious as its name implies. Shortly after the Big Bang, our universe was filled with glowing plasma, or ionized gas. As the universe cooled and expanded, electrons and protons began to bind together to form neutral hydrogen atoms (one proton and one electron each). The last of the light from the Big Bang escaped (becoming what we now detect as the Cosmic Microwave Background [CMB]).

    CMB per ESA/Planck
    CMB per ESA/Planck

    The universe would have been a dark place, with no sources of light to reveal this cooling, neutral hydrogen gas.

    Some of that gas would have begun coalescing into dense clumps, pulled together by gravity. As these clumps grew larger, they would become stars and eventually galaxies. Slowly, starlight would begin to shine in the universe. Eventually, as the early stars grew in numbers and brightness, they would have emitted enough ultraviolet light to “reionize” the universe by stripping electrons off neutral hydrogen atoms, leaving behind individual protons. This process created a hot plasma of free electrons and protons. At this point, the light from star and galaxy formation could travel freely across space and illuminate the universe. It is important to note here, astronomers are currently unsure whether the energy responsible for reionization came from stars in the early-forming galaxies; rather, it might have come from hot gas surrounding massive black holes or some even more exotic source such as decaying dark matter.

    The universe’s first stars, believed to be 30 to 300 times as massive as our Sun and millions of times as bright, would have burned for only a few million years before dying in tremendous explosions, or “supernovae.” These explosions spewed the recently manufactured chemical elements of stars outward into the universe before the expiring stars collapsed into black holes.

    Astronomers know the universe became reionized because when they look back at quasars — incredibly bright objects thought to be powered by supermassive black holes — in the distant universe, they don’t see the dimming of their light that would occur if the light passed through a fog of neutral hydrogen gas. While they find clouds of neutral hydrogen gas, they see almost no signs of neutral hydrogen gas in the matter located in the space between galaxies. This means that at some point the matter was reionized. Exactly when this occurred is one of the questions Webb will help answer, by looking for glimpses of very distant objects still dimmed by neutral hydrogen gas.

    Much remains to be uncovered about the time of reionization. The universe right after the Big Bang would have consisted of hydrogen, helium, and a small amount of lithium. But the stars we see today also contain heavier elements — elements that are created inside stars. So how did those first stars form from such limited ingredients? Webb may not be able to see the very first stars of the Dark Ages, but it’ll witness the generation of stars immediately following, and analyze the kinds of materials they contain.

    Webb’s ability to see the infrared light from the most distant objects in the universe will allow it to truly identify the sources that gave rise to reionization. For the first time, we will be able to see the stars and quasars that unleashed enough energy to illuminate the universe again.

    2
    Figure 2: JWST will be able to see back to when the first bright objects (stars and galaxies) were forming in the early universe. Credit: STScI. http://jwst.nasa.gov/firstlight.html

    Early Galaxies:

    Webb will also show us how early galaxies formed from those first clumps of stars. Scientists suspect the black holes born from the explosions of the earliest stars (supernovae) devoured gas and stars around them, becoming the extremely bright objects called “mini-quasars.” The mini-quasars, in turn, may have grown and merged to become the huge black holes found in the centers of present-day galaxies. Webb will try to find and understand these supernovae and mini-quasars to put theories of early galaxy formation to the test. Do all early galaxies have these mini-quasars or only some? These regions give off infrared light as the gas around them cools, allowing Webb to glean information about how mini-quasars in the early universe work — how hot they are, for instance, and how dense.

    Webb will show us whether the first galaxies formed along lines and webs of dark matter, as expected, and when. Right now we know the first galaxies formed anywhere from 378,000 years to 1 billion years after the Big Bang. Many models have been created to explain which era gave rise to galaxies, but Webb will pinpoint the precise time period.

    Hubble is known for its deep-field images, which capture slices of the universe throughout time. But these images stop at the point beyond which Hubble’s vision cannot reach. Webb will fill in the gaps in these images, extending them back to the Dark Ages. Working together, Hubble and Webb will help us visualize much more of the universe than we ever have before, creating for us an unprecedented picture that stretches from the current day to the beginning of the recognizable universe.

    NASA/ESA/CSA Webb Telescope annotated
    NASA/ESA/CSA Webb Telescope annotated
    http://webbtelescope.org/gallery

    Resources:

    https://frontierfields.org/2016/07/21/the-final-frontier-of-the-universe/

    http://hubble25th.org/science/8

    http://webbtelescope.org/article/13

    See the full article here .

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    Frontier Fields draws on the power of massive clusters of galaxies to unleash the full potential of the Hubble Space Telescope. The gravity of these clusters warps and magnifies the faint light of the distant galaxies behind them. Hubble captures the boosted light, revealing the farthest galaxies humanity has ever encountered, and giving us a glimpse of the cosmos to be unveiled by the James Webb Space Telescope.

    NASA Hubble Telescope
    Hubble
    NASA James Webb Telescope
    Webb

     
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