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  • richardmitnick 11:35 am on August 5, 2019 Permalink | Reply
    Tags: , , , , , operated by the school of physics of U Sidney AU, Swinburne University of Technology, UTMOST-Molonglo Observatory Synthesis Telescope (MOST) a radio telescope operating at 843 mhz, Wael Farah developed the FRB detection system and is the first person to discover FRBs in real-time with a fully automated machine learning system.   

    From Swinburne University of Technology: “Swinburne uses AI to detect fast radio bursts in real-time” 

    Swinburne U bloc

    From Swinburne University of Technology

    5 August 2019
    Katherine Moody

    1
    An artist’s impression of the fast radio burst detected on October 17 2018 at the Molonglo Radio Telescope near Canberra, Australia. Credit: James Josephides/Swinburne

    UTMOST-Molonglo Observatory Synthesis Telescope (MOST) a radio telescope operating at 843 mhz, operated by the school of physics of U Sidney, AU

    A Swinburne PhD student has built an automated system that uses artificial intelligence (AI) to revolutionise our ability to detect and capture fast radio bursts (FRBs) in real-time.

    FRBs are mysterious and powerful flashes of radio waves from space, thought to originate billions of light years from the Earth. They last for only a few milliseconds (a thousandth of a second) and their cause is one of astronomy’s biggest puzzles.

    Wael Farah developed the FRB detection system, and is the first person to discover FRBs in real-time with a fully automated, machine learning system. Mr Farah’s system has already identified five bursts – including one of the most energetic ever detected, as well as the broadest.

    His results have been published in the Monthly Notices of the Royal Astronomical Society.

    Capturing fast radio bursts in real-time

    Mr Farah trained the on-site computer at the Molonglo Radio Observatory near Canberra to recognise the signs and signatures of FRBs, and trigger an immediate capture of the finest details seen to date.

    The bursts were detected within seconds of their arrival at the Molonglo Radio Telescope, producing high quality data that allowed Swinburne researchers to study their structure accurately, and gather clues about their origin.

    Mr Farah says his interest in FRBs comes from the fact they can potentially be used to study matter around and between galaxies that is otherwise almost impossible to see.

    “It is fascinating to discover that a signal that travelled halfway through the universe, reaching our telescope after a journey of a few billion years, exhibits complex structure, like peaks separated by less than a millisecond,” he says.

    Molonglo project scientist, Dr Chris Flynn says: “Wael has used machine learning on our high-performance computing cluster to detect and save FRBs from amongst millions of other radio events, such as mobile phones, lightning storms, and signals from the Sun and from pulsars.”

    Australian Research Council Laureate Fellow and project leader, Professor Matthew Bailes says: “Molonglo’s real-time detection system allows us to fully exploit its high time and frequency resolution and probe FRB properties that were previously unobtainable.”

    2
    One of the FRBs shows remarkable structure in time and radio frequency. The fine details seen here could only be captured because the computers had been trained to spot FRBs within seconds of their arrival at the Earth. Image credit: Wael Farah/Swinburne

    The five bursts were found as part of the UTMOST FRB search program – a joint collaboration between Swinburne and the University of Sydney. The Molonglo telescope is owned by the University of Sydney.

    World-first discoveries

    In June, Swinburne astrophysicists Dr Adam Deller and Dr Ryan Shannon, from the Centre for Astrophysics and Supercomputing, were part of a team that determined the precise location of a one-off FRB for the first time.

    Dr Shannon also led the discovery of 20 FRBS in 2018, nearly doubling the known number of bursts at that time.

    See the full article here .

    Please help promote STEM in your local schools.

    Stem Education Coalition

    Swinburne U Campus

    Swinburne University of Technology (often simply called Swinburne) is an Australian public university based in Melbourne, Victoria. It was founded in 1908 as the Eastern Suburbs Technical College by George Swinburne in order to serve those without access to further education in Melbourne’s eastern suburbs. Its main campus is located in Hawthorn, a suburb of Melbourne which is located 7.5 km from the Melbourne central business district.

    In addition to its main Hawthorn campus, Swinburne has campuses in the Melbourne metropolitan area at Wantirna and Croydon as well as a campus in Sarawak, Malaysia.
    In the 2016 QS World University Rankings, Swinburne was ranked 32nd for art and design, making it one of the top art and design schools in Australia and the world.

     
  • richardmitnick 7:08 am on July 25, 2019 Permalink | Reply
    Tags: "A Speedier Check of Models", , ARC Centre of Excellence in All Sky Astrophysics, , , , , Journal of Open Source Software, PRISM-Probabilistic Regression Instrument for Simulating Models, Swinburne University of Technology   

    From AAS NOVA: “A Speedier Check of Models” 

    AASNOVA

    From AAS NOVA

    24 July 2019
    Susanna Kohler

    1
    An output from Meraxes, a galaxy formation model. A new study explores how scientists can more efficiently analyze increasingly complex models. [Meraxes/Simon Mutch]

    Astronomy is driven forward by a combination of novel observations and complex, inventive modeling. How can astronomers better analyze their models? A new study presents a tool for the job — and is also the first article published under a new partnership between the American Astronomical Society (AAS) and the Journal of Open Source Software.

    Exploring a Complex Universe

    Modeling complicated astronomical systems is an important part of how we work to understand the universe. As technology advances, models have become increasingly more complex, encompassing more and more parameters. Complex models can do a better job of describing the astronomical systems we observe, but they’re also more challenging — and time-consuming — to analyze to see how well they might fit data.

    2
    Reconstruction of a multi-Gaussian model with 12 parameters using two techniques: normal MCMC parameter sampling (right column) and hybrid PRISM+MCMC parameter sampling (left column). The reconstruction is shown as a blue solid line, and the true model is shown as a dashed black line. The different rows represent increasing iterations. The hybrid reconstruction fits the known data better after fewer iterations — effectively analyzing the model 16 times faster than the normal MCMC approach. [van der Velden et al. 2019]

    One approach astronomers often use to analyze many-parameter models is Markov Chain Monte Carlo (MCMC) methods. With MCMC methods, instead of fully evaluating a model throughout parameter space, you randomly sample the model in a variety of places. This provides a general idea of the behavior of the model without requiring the time and computing investment of a full analysis.

    While MCMC methods are generally robust, they can be quite slow — you might spend a lot of time sampling uninteresting parts of parameter space rather than focusing on the ones that are most likely to describe your system. To address this problem, a team of scientists led by Ellert van der Velden (Swinburne University of Technology and ARC Centre of Excellence in All Sky Astrophysics, Australia) have developed a new tool: a software package they call Probabilistic Regression Instrument for Simulating Models, or PRISM.

    Let’s Speed Up the Process

    How does PRISM work? When given a model to analyze, PRISM uses clever statistical methods to create an approximation of the model and iteratively predict which regions of parameter space aren’t of interest. This allows the user to home in on the interesting regions and explore the general behavior of a model very quickly. This algorithm can be used either alone or in conjunction with MCMC methods to analyze models more efficiently.

    PRISM’s approach isn’t new: these techniques have previously been used to analyze models in a variety of scientific disciplines, including the study of whales, oil reservoirs, galaxy formation, disease, and biological systems. But PRISM takes the techniques and neatly bundles them up into a python software package that anyone can use to analyze their models — a valuable tool for astronomers and other scientists alike!

    A New Partnership for Software

    Want more assurance about this software? You’ve got it! Van der Velden and collaborators’ article on PRISM, published in ApJS, is just one of a pair of publications; the second is the scrutinized software itself.

    Under a new agreement between the AAS and the Journal of Open Source Software (JOSS), scientists submitting articles about astronomical software to AAS journals may choose not only to have their article reviewed, but also to have the software itself reviewed at JOSS in parallel. When both review processes are complete, the reviewed software is linked with the paper describing it in AAS journals.

    The article presenting PRISM is the first of these simultaneous reviews to be conducted and published, and we expect many more to come! Software plays such an integral role in the study of astronomy today, and AAS publishing is pleased to help ensure that these valuable tools are shared.

    Citation

    “Model Dispersion with PRISM: An Alternative to MCMC for Rapid Analysis of Models,” Ellert van der Velden et al 2019 ApJS 242 22.
    https://iopscience.iop.org/article/10.3847/1538-4365/ab1f7d

    “Model dispersion with PRISM; an alternative to MCMC for rapid analysis of models,” van der Velden 2019 Journal of Open Source Software, 4(38) 1229.
    http://joss.theoj.org/papers/10.21105/joss.01229

    See the full article here .


    five-ways-keep-your-child-safe-school-shootings

    Please help promote STEM in your local schools.

    Stem Education Coalition

    1

    AAS Mission and Vision Statement

    The mission of the American Astronomical Society is to enhance and share humanity’s scientific understanding of the Universe.

    The Society, through its publications, disseminates and archives the results of astronomical research. The Society also communicates and explains our understanding of the universe to the public.
    The Society facilitates and strengthens the interactions among members through professional meetings and other means. The Society supports member divisions representing specialized research and astronomical interests.
    The Society represents the goals of its community of members to the nation and the world. The Society also works with other scientific and educational societies to promote the advancement of science.
    The Society, through its members, trains, mentors and supports the next generation of astronomers. The Society supports and promotes increased participation of historically underrepresented groups in astronomy.
    The Society assists its members to develop their skills in the fields of education and public outreach at all levels. The Society promotes broad interest in astronomy, which enhances science literacy and leads many to careers in science and engineering.

    Adopted June 7, 2009

     
  • richardmitnick 2:47 pm on April 16, 2019 Permalink | Reply
    Tags: "Swinburne joins Australia’s multi-billion dollar smart satellite revolution", SmartSat CRC, Swinburne University of Technology   

    From Swinburne University of Technology: “Swinburne joins Australia’s multi-billion dollar smart satellite revolution” 

    Swinburne U bloc

    From Swinburne University of Technology

    16 April 2019

    Associate Professor Alan Duffy
    9214 3876
    aduffy@swin.edu.au
    @astroduff

    1
    South Australian Premier Steven Marshall, Minister for Industry, Science and Technology, Karen Andrews and SmartSat CRC Swinburne Academic Lead Associate Professor Alan Duffy at the launch of the CRC.

    Swinburne will be a key player in the new Cooperative Research Centre for Smart Satellite Technologies and Analytics – the SmartSat CRC
    The SmartSat CRC is set to help meet the Australian Space Agency’s goal of lifting Australia’s space industry to $12 billion, generating an extra 20,000 jobs by 2030

    Swinburne will be a key player in one of the most significant space industry research concentrations in Australia, as part of a new Cooperative Research Centre for Smart Satellite Technologies and Analytics – The SmartSat CRC.

    The new CRC is a national research powerhouse involving a $190 million investment in cash and in-kind from 82 research and industry partners.

    With the addition of $55 million of federal government funding through the Department of Industry, Science and Technology’s successful CRC program, the SmartSat CRC will be the biggest investment in space industry research and development in our history. It is set to help meet the Australian Space Agency’s goal of lifting Australia’s space industry to $12 billion, generating an extra 20,000 jobs by 2030.

    The bid was led by the University of South Australia (UniSA) in partnership with Nova Systems.

    Bid leader and SmartSat CEO designate, UniSA’s Professor Andy Koronios, says the CRC will be a game changer for Australia’s space economy.

    “Globally space technologies and industries are worth more than $500 billion but that success has been underpinned by serious global investment in research,” Professor Koronios says.

    “Australia has had a strong pedigree and a long history in space with excellent scientific capabilities in instrumentation and communications technologies but until now, the research has not been brought together to build a new industry for Australia, and to capitalise on the exponential growth of the global space economy.

    “Our goal in bringing together the bid for SmartSat was to show the huge potential and capacity there is in Australia to make an impact globally by developing leapfrogging technologies in areas where we have some of the best expertise on the planet – AI, advanced communications and remote sensing analytics,” Professor Koronios says.

    “We are excited to bring Swinburne’s world-leading capabilities in astronomical data processing and visualisation to bear on the enormous opportunities the SmartSat CRC will bring to drive the growth of the Australian space industry,” says Swinburne Deputy Vice-Chancellor (Research and Development) Professor Aleksandar Subic.

    “The challenges facing our industry partners within the CRC are of a global scale and we can help solve them with the cutting-edge machine learning and AI techniques developed at Swinburne as part of our internationally recognised Industry 4.0 capability.”

    The new CRC will be headquartered in South Australia but will establish state nodes to ensure that the whole of the nation is involved in the development of smart satellite technologies which will meet Australia’s needs to secure its defence, telecommunications and monitoring technologies into the future.

    Other partners in the CRC include Australian-based global companies such as AIRBUS, BAE, MDA, Northrop Grumman, Saab, SciSys, Dassault Systems, and THALES; Australian companies – Nova Systems, OPTUS, SHOAL, and FrontierSI; Australian startups – including X-Lab, Myriota, Fluorosat, Fleet, Innovor, Lyrebird, Delta-V and x-lab; Australian universities and research organisations – UniSA, ANU, UNSW, RMIT, QUT, Curtin, CSIRO, DST, the Universities of Queensland, Adelaide, Western Australia and Western Sydney; and international collaborators, UCL, Catapult, NASA, the European Space Agency and the National University of Singapore among many more.

    See the full article here .

    five-ways-keep-your-child-safe-school-shootings

    Please help promote STEM in your local schools.

    Stem Education Coalition

    Swinburne U Campus

    Swinburne is a large and culturally diverse organisation. A desire to innovate and bring about positive change motivates our students and staff. The result is in an institution that grows and evolves each year.

    More than 100 years ago Swinburne opened its doors with a simple premise in mind: to provide education to a section of society otherwise denied further education.

    More than a century later, we continue to persevere in our commitment to not only provide, but also transform education through strong industry engagement, social inclusion, a desire to innovate and, above all, a determination to create positive change.

     
  • richardmitnick 9:52 am on April 13, 2018 Permalink | Reply
    Tags: , , , , , , New WM Keck Observatory Remote Viewing Facility opens at Swinburne, Swinburne University of Technology   

    From Swinburne: “New WM Keck Observatory Remote Viewing Facility opens at Swinburne” 

    Swinburne U bloc

    Swinburne University of Technology

    12 April 2018

    Lea Kivivali
    +61 3 9214 5428
    lkivivali@swin.edu.au


    Keck Observatory, Maunakea, Hawaii, USA.4,207 m (13,802 ft), above sea level, showing also NASA’s IRTF and NAOJ Subaru

    World-class facility enables researchers to remotely control the twin Keck Observatory telescopes in Hawaii from Hawthorn.
    Swinburne researchers have access to the observatory for up to 10 nights a year.
    The facility is partially funded through a donation from the Eric Ormond Baker Charitable fund.

    Pioneering astrophysics research in Australia has received a boost with the launch of the WM Keck Observatory Remote Viewing Facility at Swinburne University of Technology’s Luton Lane offices in Hawthorn.

    This world-class facility enables researchers and astronomy students to remotely control the twin Keck Observatory telescopes – the world’s most scientifically productive optical and infrared telescopes – based in Hawaii.

    More than 9000 kilometres from the observatory, Swinburne astronomers have been able to control the Keck telescopes with a direct video link to the telescopes since 2009 from a small on-campus control room.

    Deputy Vice-Chancellor (Research and Development), Professor Aleksandar Subic, says the Caltech partnership and access to Keck remote viewing and observation has allowed Swinburne researchers to conduct world leading research that is leading to new discoveries and transforming knowledge.

    A strategic research agreement with the California Institute for Technology (Caltech) for a further five years gives Swinburne access to the W M Keck Observatory for up to 10 nights a year until 2023.

    “The potential discoveries have the ability to answer some of life’s biggest questions and lead to breakthrough technologies that could benefit many fields and industries. We are already seeing a huge impact that the recent discovery of gravitational waves is having,” Professor Subic says.

    2
    No image caption or credit.

    The new facility can accommodate larger research teams and provides a new base for the Deeper, Wider Faster astrophysics program that has been searching for Fast Radio Bursts, the fastest explosions in the Universe.

    “The ability to remotely operate the Keck telescopes from Melbourne has placed the Swinburne campus in the frontline of international astrophysics,” says Director of Swinburne’s Centre for Astrophysics and Supercomputing, Professor Karl Glazebrook.

    “It is really exciting to be in the remote observing room and see, in real time, the newest and faintest signals from the most distant objects coming in live. It allows Swinburne astronomers to make decisions on the spot that lead to major discoveries about the Universe and facilitates wide engagement of our staff and students in these moments.”

    Using the W M Keck Observatory’s cutting-edge instrumentation, Swinburne astronomers have produced landmark discoveries about the Universe such as:

    The monster galaxy that grew up too fast.
    New method solves 40 year-old mystery on the size of shadowy galaxies.
    New spin on star forming galaxies.
    The detection of superluminous supernovae.

    Astronomers from other research centres will also have access to the new facility.

    Researchers will also be able to remotely control the Anglo-Australian Telescope in New South Wales.

    The new facility was unveiled at a special event held for Swinburne alumni and donors. It has been partially funded through a generous donation from the Eric Ormond Baker Charitable fund, represented by trustee and Swinburne Online staff member Graeme Baker, and managed by Equity Trustees.

    See the full article here .

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

    Swinburne U Campus

    Swinburne is a large and culturally diverse organisation. A desire to innovate and bring about positive change motivates our students and staff. The result is in an institution that grows and evolves each year.

     
  • richardmitnick 8:20 am on March 7, 2018 Permalink | Reply
    Tags: , Dell EMC OzSTAR supercomputer, , , Swinburne University of Technology   

    From Swinburne University of Technology: “Swinburne supercomputer to be one of the most powerful in Australia” 

    Swinburne U bloc

    Swinburne University of Technology

    7 March 2018
    Katherine Towers
    +61 3 9214 5789
    ktowers@swin.edu.au

    1
    Swinburne U of T OzSTAR supercomputer

    Swinburne has launched one of the most powerful computers in the country in a bid to help unlock the secrets of the Universe.

    The new $4 million supercomputer, OzSTAR, is based at Swinburne’s Hawthorn campus and features a performance peak of 1.2 petaflops.

    The computer, powered by Dell EMC, launches Swinburne into the petascale era of supercomputing and will enable the Swinburne-based Australian Research Council Centre of Excellence for Gravitational Wave Discovery’s (OzGrav) to search for gravitational waves and study the extreme physics of black holes and warped spacetime.

    2
    The supercomputer features custom artwork designed by Swinburne graduate Justin Pedler (right) and visual arts agency Apparition Media.

    3
    The finished design features gas swirling around two black holes.

    OzGrav Director, Professor Matthew Bailes, says OzSTAR will be used to shift through reams of data and be powerful enough to search for coalescing black holes and neutron stars in real time.

    “In one second, OzSTAR can perform 10,000 calculations for every one of the 100 billion starts in our galaxy,” says Professor Bailes.

    Manager of the supercomputer, Professor Jarrod Hurley, says OzSTAR maintains Swinburne as an academic leader in supercomputing with a focus on hybrid CPU-GPU technology across the system.

    He says the supercomputer will also be key in enabling Swinburne’s Data Science Research Institute to tackle future data science challenges such as machine learning, deep learning, database interrogation and visualisation.

    Understanding gravitational waves

    Gravitational waves were first predicted 100 years ago by Albert Einstein in his theory of General Relativity, which described how gravity warps and distorts space-time.

    Einstein’s mathematics showed that massive accelerating objects (such as neutron stars or black holes orbiting each other) distort both space and time and emit a new type of radiation, known as gravitational waves.

    But these gravitational waves remained undetected for a century until advances in detector sensitivity at the Advanced Laser Interferometer Gravitational-Wave Observatory (aLIGO) in the US enabled their detection in September 2015.

    Shortly after being switched on, aLIGO physically sensed distortions in space-time itself caused by passing gravitational waves generated by two colliding black holes nearly 1.3 billion light years away that moved its mirrors by just 1/10000th of the width of a proton.

    UC Santa Cruz

    UC Santa Cruz

    14

    A UC Santa Cruz special report

    Tim Stephens

    Astronomer Ryan Foley says “observing the explosion of two colliding neutron stars” [see https://sciencesprings.wordpress.com/2017/10/17/from-ucsc-first-observations-of-merging-neutron-stars-mark-a-new-era-in-astronomy ]–the first visible event ever linked to gravitational waves–is probably the biggest discovery he’ll make in his lifetime. That’s saying a lot for a young assistant professor who presumably has a long career still ahead of him.

    2
    The first optical image of a gravitational wave source was taken by a team led by Ryan Foley of UC Santa Cruz using the Swope Telescope at the Carnegie Institution’s Las Campanas Observatory in Chile. This image of Swope Supernova Survey 2017a (SSS17a, indicated by arrow) shows the light emitted from the cataclysmic merger of two neutron stars. (Image credit: 1M2H Team/UC Santa Cruz & Carnegie Observatories/Ryan Foley)

    Carnegie Institution Swope telescope at Las Campanas, Chile, 100 kilometres (62 mi) northeast of the city of La Serena. near the north end of a 7 km (4.3 mi) long mountain ridge. Cerro Las Campanas, near the southern end and over 2,500 m (8,200 ft) high, at Las Campanas, Chile

    A neutron star forms when a massive star runs out of fuel and explodes as a supernova, throwing off its outer layers and leaving behind a collapsed core composed almost entirely of neutrons. Neutrons are the uncharged particles in the nucleus of an atom, where they are bound together with positively charged protons. In a neutron star, they are packed together just as densely as in the nucleus of an atom, resulting in an object with one to three times the mass of our sun but only about 12 miles wide.

    “Basically, a neutron star is a gigantic atom with the mass of the sun and the size of a city like San Francisco or Manhattan,” said Foley, an assistant professor of astronomy and astrophysics at UC Santa Cruz.

    These objects are so dense, a cup of neutron star material would weigh as much as Mount Everest, and a teaspoon would weigh a billion tons. It’s as dense as matter can get without collapsing into a black hole.

    THE MERGER

    Like other stars, neutron stars sometimes occur in pairs, orbiting each other and gradually spiraling inward. Eventually, they come together in a catastrophic merger that distorts space and time (creating gravitational waves) and emits a brilliant flare of electromagnetic radiation, including visible, infrared, and ultraviolet light, x-rays, gamma rays, and radio waves. Merging black holes also create gravitational waves, but there’s nothing to be seen because no light can escape from a black hole.

    Foley’s team was the first to observe the light from a neutron star merger that took place on August 17, 2017, and was detected by the Advanced Laser Interferometer Gravitational-Wave Observatory (LIGO).


    VIRGO Gravitational Wave interferometer, near Pisa, Italy

    Caltech/MIT Advanced aLigo Hanford, WA, USA installation


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

    Cornell SXS, the Simulating eXtreme Spacetimes (SXS) project

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

    ESA/eLISA the future of gravitational wave research

    1
    Skymap showing how adding Virgo to LIGO helps in reducing the size of the source-likely region in the sky. (Credit: Giuseppe Greco (Virgo Urbino group)

    Now, for the first time, scientists can study both the gravitational waves (ripples in the fabric of space-time), and the radiation emitted from the violent merger of the densest objects in the universe.

    3
    The UC Santa Cruz team found SSS17a by comparing a new image of the galaxy N4993 (right) with images taken four months earlier by the Hubble Space Telescope (left). The arrows indicate where SSS17a was absent from the Hubble image and visible in the new image from the Swope Telescope. (Image credits: Left, Hubble/STScI; Right, 1M2H Team/UC Santa Cruz & Carnegie Observatories/Ryan Foley)

    It’s that combination of data, and all that can be learned from it, that has astronomers and physicists so excited. The observations of this one event are keeping hundreds of scientists busy exploring its implications for everything from fundamental physics and cosmology to the origins of gold and other heavy elements.


    A small team of UC Santa Cruz astronomers were the first team to observe light from two neutron stars merging in August. The implications are huge.

    ALL THE GOLD IN THE UNIVERSE

    It turns out that the origins of the heaviest elements, such as gold, platinum, uranium—pretty much everything heavier than iron—has been an enduring conundrum. All the lighter elements have well-explained origins in the nuclear fusion reactions that make stars shine or in the explosions of stars (supernovae). Initially, astrophysicists thought supernovae could account for the heavy elements, too, but there have always been problems with that theory, says Enrico Ramirez-Ruiz, professor and chair of astronomy and astrophysics at UC Santa Cruz.

    4
    The violent merger of two neutron stars is thought to involve three main energy-transfer processes, shown in this diagram, that give rise to the different types of radiation seen by astronomers, including a gamma-ray burst and a kilonova explosion seen in visible light. (Image credit: Murguia-Berthier et al., Science)

    A theoretical astrophysicist, Ramirez-Ruiz has been a leading proponent of the idea that neutron star mergers are the source of the heavy elements. Building a heavy atomic nucleus means adding a lot of neutrons to it. This process is called rapid neutron capture, or the r-process, and it requires some of the most extreme conditions in the universe: extreme temperatures, extreme densities, and a massive flow of neutrons. A neutron star merger fits the bill.

    Ramirez-Ruiz and other theoretical astrophysicists use supercomputers to simulate the physics of extreme events like supernovae and neutron star mergers. This work always goes hand in hand with observational astronomy. Theoretical predictions tell observers what signatures to look for to identify these events, and observations tell theorists if they got the physics right or if they need to tweak their models. The observations by Foley and others of the neutron star merger now known as SSS17a are giving theorists, for the first time, a full set of observational data to compare with their theoretical models.

    According to Ramirez-Ruiz, the observations support the theory that neutron star mergers can account for all the gold in the universe, as well as about half of all the other elements heavier than iron.

    RIPPLES IN THE FABRIC OF SPACE-TIME

    Einstein predicted the existence of gravitational waves in 1916 in his general theory of relativity, but until recently they were impossible to observe. LIGO’s extraordinarily sensitive detectors achieved the first direct detection of gravitational waves, from the collision of two black holes, in 2015. Gravitational waves are created by any massive accelerating object, but the strongest waves (and the only ones we have any chance of detecting) are produced by the most extreme phenomena.

    Two massive compact objects—such as black holes, neutron stars, or white dwarfs—orbiting around each other faster and faster as they draw closer together are just the kind of system that should radiate strong gravitational waves. Like ripples spreading in a pond, the waves get smaller as they spread outward from the source. By the time they reached Earth, the ripples detected by LIGO caused distortions of space-time thousands of times smaller than the nucleus of an atom.

    The rarefied signals recorded by LIGO’s detectors not only prove the existence of gravitational waves, they also provide crucial information about the events that produced them. Combined with the telescope observations of the neutron star merger, it’s an incredibly rich set of data.

    LIGO can tell scientists the masses of the merging objects and the mass of the new object created in the merger, which reveals whether the merger produced another neutron star or a more massive object that collapsed into a black hole. To calculate how much mass was ejected in the explosion, and how much mass was converted to energy, scientists also need the optical observations from telescopes. That’s especially important for quantifying the nucleosynthesis of heavy elements during the merger.

    LIGO can also provide a measure of the distance to the merging neutron stars, which can now be compared with the distance measurement based on the light from the merger. That’s important to cosmologists studying the expansion of the universe, because the two measurements are based on different fundamental forces (gravity and electromagnetism), giving completely independent results.

    “This is a huge step forward in astronomy,” Foley said. “Having done it once, we now know we can do it again, and it opens up a whole new world of what we call ‘multi-messenger’ astronomy, viewing the universe through different fundamental forces.”

    IN THIS REPORT

    Neutron stars
    A team from UC Santa Cruz was the first to observe the light from a neutron star merger that took place on August 17, 2017 and was detected by the Advanced Laser Interferometer Gravitational-Wave Observatory (LIGO)

    5
    Graduate students and post-doctoral scholars at UC Santa Cruz played key roles in the dramatic discovery and analysis of colliding neutron stars.Astronomer Ryan Foley leads a team of young graduate students and postdoctoral scholars who have pulled off an extraordinary coup. Following up on the detection of gravitational waves from the violent merger of two neutron stars, Foley’s team was the first to find the source with a telescope and take images of the light from this cataclysmic event. In so doing, they beat much larger and more senior teams with much more powerful telescopes at their disposal.

    “We’re sort of the scrappy young upstarts who worked hard and got the job done,” said Foley, an untenured assistant professor of astronomy and astrophysics at UC Santa Cruz.

    7
    David Coulter, graduate student

    The discovery on August 17, 2017, has been a scientific bonanza, yielding over 100 scientific papers from numerous teams investigating the new observations. Foley’s team is publishing seven papers, each of which has a graduate student or postdoc as the first author.

    “I think it speaks to Ryan’s generosity and how seriously he takes his role as a mentor that he is not putting himself front and center, but has gone out of his way to highlight the roles played by his students and postdocs,” said Enrico Ramirez-Ruiz, professor and chair of astronomy and astrophysics at UC Santa Cruz and the most senior member of Foley’s team.

    “Our team is by far the youngest and most diverse of all of the teams involved in the follow-up observations of this neutron star merger,” Ramirez-Ruiz added.

    8
    Charles Kilpatrick, postdoctoral scholar

    Charles Kilpatrick, a 29-year-old postdoctoral scholar, was the first person in the world to see an image of the light from colliding neutron stars. He was sitting in an office at UC Santa Cruz, working with first-year graduate student Cesar Rojas-Bravo to process image data as it came in from the Swope Telescope in Chile. To see if the Swope images showed anything new, he had also downloaded “template” images taken in the past of the same galaxies the team was searching.

    9
    Ariadna Murguia-Berthier, graduate student

    “In one image I saw something there that was not in the template image,” Kilpatrick said. “It took me a while to realize the ramifications of what I was seeing. This opens up so much new science, it really marks the beginning of something that will continue to be studied for years down the road.”

    At the time, Foley and most of the others in his team were at a meeting in Copenhagen. When they found out about the gravitational wave detection, they quickly got together to plan their search strategy. From Copenhagen, the team sent instructions to the telescope operators in Chile telling them where to point the telescope. Graduate student David Coulter played a key role in prioritizing the galaxies they would search to find the source, and he is the first author of the discovery paper published in Science.

    10
    Matthew Siebert, graduate student

    “It’s still a little unreal when I think about what we’ve accomplished,” Coulter said. “For me, despite the euphoria of recognizing what we were seeing at the moment, we were all incredibly focused on the task at hand. Only afterward did the significance really sink in.”

    Just as Coulter finished writing his paper about the discovery, his wife went into labor, giving birth to a baby girl on September 30. “I was doing revisions to the paper at the hospital,” he said.

    It’s been a wild ride for the whole team, first in the rush to find the source, and then under pressure to quickly analyze the data and write up their findings for publication. “It was really an all-hands-on-deck moment when we all had to pull together and work quickly to exploit this opportunity,” said Kilpatrick, who is first author of a paper comparing the observations with theoretical models.

    11
    César Rojas Bravo, graduate student

    Graduate student Matthew Siebert led a paper analyzing the unusual properties of the light emitted by the merger. Astronomers have observed thousands of supernovae (exploding stars) and other “transients” that appear suddenly in the sky and then fade away, but never before have they observed anything that looks like this neutron star merger. Siebert’s paper concluded that there is only a one in 100,000 chance that the transient they observed is not related to the gravitational waves.

    Ariadna Murguia-Berthier, a graduate student working with Ramirez-Ruiz, is first author of a paper synthesizing data from a range of sources to provide a coherent theoretical framework for understanding the observations.

    Another aspect of the discovery of great interest to astronomers is the nature of the galaxy and the galactic environment in which the merger occurred. Postdoctoral scholar Yen-Chen Pan led a paper analyzing the properties of the host galaxy. Enia Xhakaj, a new graduate student who had just joined the group in August, got the opportunity to help with the analysis and be a coauthor on the paper.

    12
    Yen-Chen Pan, postdoctoral scholar

    “There are so many interesting things to learn from this,” Foley said. “It’s a great experience for all of us to be part of such an important discovery.”

    13
    Enia Xhakaj, graduate student

    IN THIS REPORT

    Scientific Papers from the 1M2H Collaboration

    Coulter et al., Science, Swope Supernova Survey 2017a (SSS17a), the Optical Counterpart to a Gravitational Wave Source

    Drout et al., Science, Light Curves of the Neutron Star Merger GW170817/SSS17a: Implications for R-Process Nucleosynthesis

    Shappee et al., Science, Early Spectra of the Gravitational Wave Source GW170817: Evolution of a Neutron Star Merger

    Kilpatrick et al., Science, Electromagnetic Evidence that SSS17a is the Result of a Binary Neutron Star Merger

    Siebert et al., ApJL, The Unprecedented Properties of the First Electromagnetic Counterpart to a Gravitational-wave Source

    Pan et al., ApJL, The Old Host-galaxy Environment of SSS17a, the First Electromagnetic Counterpart to a Gravitational-wave Source

    Murguia-Berthier et al., ApJL, A Neutron Star Binary Merger Model for GW170817/GRB170817a/SSS17a

    Kasen et al., Nature, Origin of the heavy elements in binary neutron star mergers from a gravitational wave event

    Abbott et al., Nature, A gravitational-wave standard siren measurement of the Hubble constant (The LIGO Scientific Collaboration and The Virgo Collaboration, The 1M2H Collaboration, The Dark Energy Camera GW-EM Collaboration and the DES Collaboration, The DLT40 Collaboration, The Las Cumbres Observatory Collaboration, The VINROUGE Collaboration & The MASTER Collaboration)

    Abbott et al., ApJL, Multi-messenger Observations of a Binary Neutron Star Merger

    PRESS RELEASES AND MEDIA COVERAGE


    Watch Ryan Foley tell the story of how his team found the neutron star merger in the video below. 2.5 HOURS.

    Press releases:

    UC Santa Cruz Press Release

    UC Berkeley Press Release

    Carnegie Institution of Science Press Release

    LIGO Collaboration Press Release

    National Science Foundation Press Release

    Media coverage:

    The Atlantic – The Slack Chat That Changed Astronomy

    Washington Post – Scientists detect gravitational waves from a new kind of nova, sparking a new era in astronomy

    New York Times – LIGO Detects Fierce Collision of Neutron Stars for the First Time

    Science – Merging neutron stars generate gravitational waves and a celestial light show

    CBS News – Gravitational waves – and light – seen in neutron star collision

    CBC News – Astronomers see source of gravitational waves for 1st time

    San Jose Mercury News – A bright light seen across the universe, proving Einstein right

    Popular Science – Gravitational waves just showed us something even cooler than black holes

    Scientific American – Gravitational Wave Astronomers Hit Mother Lode

    Nature – Colliding stars spark rush to solve cosmic mysteries

    National Geographic – In a First, Gravitational Waves Linked to Neutron Star Crash

    Associated Press – Astronomers witness huge cosmic crash, find origins of gold

    Science News – Neutron star collision showers the universe with a wealth of discoveries

    UCSC press release
    First observations of merging neutron stars mark a new era in astronomy

    Credits

    Writing: Tim Stephens
    Video: Nick Gonzales
    Photos: Carolyn Lagattuta
    Header image: Illustration by Robin Dienel courtesy of the Carnegie Institution for Science
    Design and development: Rob Knight
    Project managers: Sherry Main, Scott Hernandez-Jason, Tim Stephens

    Dark Energy Survey


    Dark Energy Camera [DECam], built at FNAL


    NOAO/CTIO Victor M Blanco 4m Telescope which houses the DECam at Cerro Tololo, Chile, housing DECam at an altitude of 7200 feet

    Gemini South telescope, Cerro Tololo Inter-American Observatory (CTIO) campus near La Serena, Chile, at an altitude of 7200 feet

    Noted in the video but not in the article:

    NASA/Chandra Telescope

    NASA/SWIFT Telescope

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

    CTIO PROMPT telescope telescope built by the University of North Carolina at Chapel Hill at Cerro Tololo Inter-American Observatory in Chilein the Chilean Andes.

    PROMPT The six domes at CTIO in Chile.

    NASA NuSTAR X-ray telescope

    See the full article here

    4
    U Swinburne Dell EMC OzSTAR supercomputer

    The supercomputer features 4140 SkyLake cores at 2.3Ghz across 107 standard compute and eight data crunching nodes, 230 NVIDIA Tesla P100 12 GB GPUs, 272 Intel Xeon Phi cores at 1.6Ghz across four C6320pKNL nodes, a high speed low latency network fabric able to move data across each building block at over 100Gbps with various features to ensure reliability and traffic flow and 5 petabyte of usable storage via the Lustre ZFS file system at 30GB/s throughput.

    See the full article here .

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

    Swinburne U Campus

    Swinburne is a large and culturally diverse organisation. A desire to innovate and bring about positive change motivates our students and staff. The result is in an institution that grows and evolves each year.

     
  • richardmitnick 12:10 pm on April 18, 2017 Permalink | Reply
    Tags: , , , , , , , Live fast die young: quiescent galaxies in the early universe, Swinburne University of Technology   

    From astrobites: “Live fast, die young: quiescent galaxies in the early universe” 

    Astrobites bloc

    Astrobites

    Apr 18, 2017
    Christopher Lovell

    Title: A massive, quiescent galaxy at redshift of z=3.717
    Authors: Karl Glazebrook, Corentin Schreiber, Ivo Labbé, Themiya Nanayakkara, Glenn G. Kacprzak, Pascal A. Oesch, Casey Papovich, Lee R Spitler, Caroline M. S. Straatman, Kim-Vy H. Tran, Tiantian Yuan
    First author’s institution: Centre for Astrophysics and Supercomputing, Swinburne University of Technology, Australia

    Status: Submitted for publication in NATURE, Open Access

    Galaxies in the early universe tend to be young and carefree. They have plenty of gas, and set about vigorously forming lots of stars. As a galaxy gets older though, it starts to run out of gas and becomes quiescent, no longer forming stars (see these bites for more details on quiescent galaxies). Theorists predict that it takes at least a few gigayears to deplete the gas, and this can be sped up by mergers and interactions with other galaxies. So, the further away we look (which corresponds to looking further back in time) the fewer quiescent galaxies we expect to see.

    Today’s paper is about the snappily named ZF-COSMOS-20115, a quiescent galaxy at the unusually high redshift of 3.7, around one and a half billion years after the big bang.

    3
    RARE FIND Galaxy ZF-COSMOS-20115, illustrated here, may be an oddity in the early universe. It formed stars rapidly, but then suddenly shut off, becoming red and dead by the time the universe was only 1.65 billion years old. Leonard Doublet/Swinburne University of Technology

    It has a mass equivalent to 170 billion suns, making it one of the most massive galaxies at this point in the universe’s history (much bigger than other similarly quiescent galaxies at this time), but it’s also very compact, less than a kiloparsec across (in comparison, our own Milky Way is ~ 50 kiloparsecs across). How did ZF-COSMOS-20115 become quiescent so quickly after forming, and is it a challenge to our current understanding of galaxy evolution?

    1
    Figure 1: Images of ZF-COSMOS-20115 with the Hubble Space Telescope (left panel), and from ground based telescopes (right panels). The left and top right images show the near-infrared, and the galaxy is clearly visible. In bottom right panel, showing visible light, the galaxy is undetected.

    In order for this galaxy to have formed so many stars and then become quiescent it must have had an enormous burst of star formation very early in its history. The authors speculate that such a burst could have been caused by a major merger between two similarly sized galaxies. Such a violent collision would have caused a huge amount of star formation in a relatively short period of time, sufficient to use up the gas reserves of both galaxies and prevent any further star formation after the merger.

    The authors argue that many current galaxy evolution models struggle to explain ZF-COSMOS-20115 – they contain galaxies of the right mass, but are still forming lots of stars. However, since this pre-print was released many of the theorists working on such models have retorted with evidence that they can produce analogues of ZF-COSMOS-20115 (see here and here). Whether these model analogues are really capturing the true nature of this galaxy or not is still up for debate. Future observations of more quiescent galaxies in the early universe will help theorists build a better picture of these young galaxies, tragically quiescent before their time…

    See the full article here .

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

    What do we do?

    Astrobites is a daily astrophysical literature journal written by graduate students in astronomy. Our goal is to present one interesting paper per day in a brief format that is accessible to undergraduate students in the physical sciences who are interested in active research.
    Why read Astrobites?

    Reading a technical paper from an unfamiliar subfield is intimidating. It may not be obvious how the techniques used by the researchers really work or what role the new research plays in answering the bigger questions motivating that field, not to mention the obscure jargon! For most people, it takes years for scientific papers to become meaningful.
    Our goal is to solve this problem, one paper at a time. In 5 minutes a day reading Astrobites, you should not only learn about one interesting piece of current work, but also get a peek at the broader picture of research in a new area of astronomy.

     
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