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  • richardmitnick 7:53 pm on June 26, 2017 Permalink | Reply
    Tags: , BNL "science raft", Large Synoptic Survey Telescope (LSST),   

    From BNL: “Brookhaven Lab Reaches Major Milestone for Large Synoptic Survey Telescope Project” 

    Brookhaven Lab

    June 26, 2017
    Stephanie Kossman
    skossman@bnl.gov
    (631) 344-8671, or

    Peter Genzer,
    genzer@bnl.gov
    (631) 344-3174

    1
    Paul O’Connor (left) and Bill Wahl (right) pictured with components of the science raft.

    Scientists at the U.S. Department of Energy’s (DOE) Brookhaven National Laboratory have completed the first “science raft” for the Large Synoptic Survey Telescope (LSST), a massive telescope designed to capture images of the universe like never before. The raft is part of the sensor array that will make up the crucial camera segment of the telescope, and its completion is the first major milestone for Brookhaven’s role in the project.

    The LSST project is a collaborative effort among more than 30 institutions from around the globe, funded primarily by DOE’s Office of Science and the National Science Foundation. SLAC National Accelerator Lab is leading the overall DOE effort, and Brookhaven is leading the conceptualization, design, construction, and qualification of the digital sensory array, the “digital film” for LSST’s camera.


    LSST Camera, built at SLAC



    LSST telescope, currently under construction at Cerro Pachón Chile, a 2,682-meter-high mountain in Coquimbo Region, in northern Chile, alongside the existing Gemini South and Southern Astrophysical Research Telescopes.

    Now under construction on a mountaintop in Chile, LSST will capture an image of the entire sky in the southern hemisphere every three nights, allowing researchers to create a time-lapse movie of the universe. Its camera will have an unparalleled field of view and, coupled with the light gathering power of the telescope, LSST will have a far greater capacity to survey the sky than has ever been previously available.

    The 3,200 megapixel sensor array being developed at Brookhaven is what will enable LSST to capture this extraordinary view when it begins operations in 2023.

    “It’s the heart of the camera,” said Bill Wahl, Science Raft Subsystem Manager of the LSST project at Brookhaven Lab. “What we’re doing here at Brookhaven represents years of great work by many talented scientists and engineers, which will lead to a collection of images that has never been seen before by anyone. It’s an exciting time for the project and especially for the Lab.”

    LSST’s scientists have designed a grid composed of more than 200 sensors, divided into 21 modules called science rafts. Each raft can function as a camera on its own but, when combined, they will stitch together a complete image of the visible sky. After years of design and construction, the first raft was qualified for use in the LSST camera in late May 2017. Brookhaven is now scheduled to construct approximately one raft per month.

    “Completion of the first raft is a big stepping stone,” said Paul O’Connor, Senior Scientist at Brookhaven Lab’s Instrumentation Division. Scientists at Brookhaven have successfully captured high-fidelity images using the newly completed raft, confirming the functionality of its design.

    Brookhaven began its LSST research and development program in 2003, with construction starting in 2014. In the time leading up to this milestone, an entire production facility, along with production and tracking software, needed to be created. During the past three years, Brookhaven and its vendors have been tackling the painstaking task of constructing these incredibly precise imaging arrays.

    The science raft “is an object that is tricky enough to build alone, but it also has to operate perfectly when in a vacuum and cooled to -100° Celsius,” O’Connor said. Cooling the rafts improves the camera’s sensitivity; however, it also causes parts to contract, making it increasingly complicated to design the rafts precisely.

    Ultimately, even with these challenges, the first raft was completed on time and the full digital sensor array is on track to be delivered to Chile by the end of 2019.

    Once operational in the Andes Mountains, LSST will serve nearly every subset of the astrophysics community. It is estimated that LSST will find tens of millions of asteroids in our solar system, in addition to offering new information about the creation of our galaxy.

    The main interest of the DOE in supporting the development of the LSST camera, however, is to investigate dark energy and dark matter – two anomalies that have baffled astrophysicists for decades.


    Dark Energy Camera [DECam], built at FNAL


    NOAO/CTIO Victor M Blanco 4m Telescope which houses the DECam at Cerro Tololo, Chile, housing DECam

    “This is what a lot of people would say is the most pressing question of fundamental physics,” O’Connor said. “The nature of dark energy and dark matter don’t fit into the rest of physics.”

    Scientists intend to use LSST to infer the spatial distribution of dark matter by looking at the way its gravitational force bends light from luminous matter (matter in the universe that emits light).

    Images captured by LSST will also be made available to the public through a full-sky viewer similar to the Google Earth platform. This technology will give students and independent scientists the opportunity to investigate dark energy and dark matter, as well as for an average person to see and explore the stars.

    For more information on LSST, please visit https://www.lsst.org/

    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 1:40 pm on June 1, 2017 Permalink | Reply
    Tags: , , , , , Large Synoptic Survey Telescope (LSST), Pan-STARRS1,   

    From Universe Today: “What Exactly Should We See When a Star Splashes into a Black Hole Event Horizon?” 

    universe-today

    Universe Today

    1 June , 2017
    Evan Gough

    1
    This artist’s impression shows the surroundings of the supermassive black hole at the heart of the active galaxy NGC 3783. Credit: ESO/M. Kornmesser

    At the center of our Milky Way galaxy dwells a behemoth.

    Sag A* NASA Chandra X-Ray Observatory 23 July 2014, the supermassive black hole at the center of the Milky Way

    An object so massive that nothing can escape its gravitational pull, not even light. In fact, we think most galaxies have one of them. They are, of course, supermassive black holes.

    Supermassive black holes are stars that have collapsed into a singularity. Einstein’s General Theory of Relativity predicted their existence. And these black holes are surrounded by what’s known as an event horizon, which is kind of like the point of no return for anything getting too close to the black hole. But nobody has actually proven the existence of the event horizon yet.

    Some theorists think that something else might lie at the center of galaxies, a supermassive object event stranger than a supermassive black hole. Theorists think these objects have somehow avoided a black hole’s fate, and have not collapsed into a singularity. They would have no event horizon, and would have a solid surface instead.

    “Our whole point here is to turn this idea of an event horizon into an experimental science, and find out if event horizons really do exist or not,” – Pawan Kumar Professor of Astrophysics, University of Texas at Austin.

    A team of researchers at the University of Texas at Austin and Harvard University have tackled the problem. Wenbin Lu, Pawan Kumar, and Ramesh Narayan wanted to shed some light onto the event horizon problem.

    They wondered about the solid surface object, and what would happen when an object like a star collided with it. They published their results in the Monthly Notices of the Royal Astronomical Society.

    The trio predicted that in the 3.5 year time-frame captured by the Pan-STAARS survey, 10 of these collisions would occur and should be represented in the data.

    Pan-STARRS1 located on Haleakala, Maui, HI, USA

    The team found none of the flare-ups they expected to see if the hard-surface theory is true.

    2
    Artist’s conception of the event horizon of a black hole. Credit: Victor de Schwanberg/Science Photo Library

    They’re hoping to improve their test with the upcoming Large Synoptic Survey Telescope (LSST) being built in Chile.


    LSST Camera, built at SLAC



    LSST telescope, currently under construction at Cerro Pachón Chile, a 2,682-meter-high mountain in Coquimbo Region, in northern Chile, alongside the existing Gemini South and Southern Astrophysical Research Telescopes.

    The LSST is a wide field telescope that will capture images of the night sky every 20 seconds over a ten-year span. Every few nights, the LSST will give us an image of the entire available night sky. This will make the study of transient objects much easier and effective.

    See the full article here .

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  • richardmitnick 7:50 am on May 27, 2017 Permalink | Reply
    Tags: , , Azimuth Advancements, , , Large Synoptic Survey Telescope (LSST)   

    From LSST: “Azimuth Advancements” 

    LSST

    Large Synoptic Survey Telescope

    1
    The telescope mount is rapidly being assembled in the factory at Asturfeito. No image credit.

    5-26-17

    Work on the Telescope Mount Assembly (TMA) by subcontractor Asturfeito in Spain is progressing rapidly. An auxiliary second level platform has been installed, providing access to the azimuth floor. In addition, azimuth radial bearings have been placed and vertical seismic stops have been trial fitted. Currently, the plan is to float the azimuth structure on the hydrostatic bearings in July, which will be the first time the base of the TMA supports the full structural load. Achieving this milestone will allow the Telescope & Site team to start doing balance calculations and planning rotational tests of the TMA.

    See the full article here .

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    LSST telescope, currently under construction at Cerro Pachón Chile
    LSST Interior
    LSST telescope, currently under construction at Cerro Pachón Chile.

    LSST/Camera, built at SLAC
    LSST/Camera, built at SLAC

    The LSST is a new kind of telescope. Currently under construction in Chile, it is being built to rapidly survey the night-time sky. Compact and nimble, the LSST will move quickly between images, yet its large mirror and large field of view—almost 10 square degrees of sky, or 40 times the size of the full moon—work together to deliver more light from faint astronomical objects than any optical telescope in the world.

    From its mountaintop site in the foothills of the Andes, the LSST will take more than 800 panoramic images each night with its 3.2 billion-pixel camera, recording the entire visible sky twice each week. Each patch of sky it images will be visited 1000 times during the survey. With a light-gathering power equal to a 6.7-m diameter primary mirror, each of its 30-second observations will be able to detect objects 10 million times fainter than visible with the human eye. A powerful data system will compare new with previous images to detect changes in brightness and position of objects as big as far-distant galaxy clusters and as small as near-by asteroids.

    The LSST’s combination of telescope, mirror, camera, data processing, and survey will capture changes in billions of faint objects and the data it provides will be used to create an animated, three-dimensional cosmic map with unprecedented depth and detail , giving us an entirely new way to look at the Universe. This map will serve a myriad of purposes, from locating that mysterious substance called dark matter and characterizing the properties of the even more mysterious dark energy, to tracking transient objects, to studying our own Milky Way Galaxy in depth. It will even be used to detect and track potentially hazardous asteroids—asteroids that might impact the Earth and cause significant damage.

    As with past technological advances that opened new windows of discovery, such a powerful system for exploring the faint and transient Universe will undoubtedly serve up surprises.

    Plans for sharing the data from LSST with the public are as ambitious as the telescope itself. Anyone with a computer will be able to view the moving map of the Universe created by the LSST, including objects a hundred million times fainter than can be observed with the unaided eye. The LSST project will provide analysis tools to enable both students and the public to participate in the process of scientific discovery. We invite you to learn more about LSST science.

    The LSST will be unique: no existing telescope or proposed camera could be retrofitted or re-designed to cover ten square degrees of sky with a collecting area of forty square meters. Named the highest priority for ground-based astronomy in the 2010 Decadal Survey, the LSST project formally began construction in July 2014.

     
  • richardmitnick 3:50 pm on May 16, 2017 Permalink | Reply
    Tags: , Blind studies, , , Large Synoptic Survey Telescope (LSST), , , , ,   

    From Symmetry: “The facts and nothing but the facts” 

    Symmetry Mag

    Symmetry

    1
    Artwork by Corinne Mucha

    05/16/17
    Manuel Gnida

    At a recent workshop on blind analysis, researchers discussed how to keep their expectations out of their results.

    Scientific experiments are designed to determine facts about our world. But in complicated analyses, there’s a risk that researchers will unintentionally skew their results to match what they were expecting to find. To reduce or eliminate this potential bias, scientists apply a method known as “blind analysis.”

    Blind studies are probably best known from their use in clinical drug trials, in which patients are kept in the dark about—or blind to—whether they’re receiving an actual drug or a placebo. This approach helps researchers judge whether their results stem from the treatment itself or from the patients’ belief that they are receiving it.

    Particle physicists and astrophysicists do blind studies, too. The approach is particularly valuable when scientists search for extremely small effects hidden among background noise that point to the existence of something new, not accounted for in the current model. Examples include the much-publicized discoveries of the Higgs boson by experiments at CERN’s Large Hadron Collider and of gravitational waves by the Advanced LIGO detector.

    LHC

    CERN/LHC Map

    CERN LHC Tunnel

    CERN LHC particles


    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

    “Scientific analyses are iterative processes, in which we make a series of small adjustments to theoretical models until the models accurately describe the experimental data,” says Elisabeth Krause, a postdoc at the Kavli Institute for Particle Astrophysics and Cosmology, which is jointly operated by Stanford University and the Department of Energy’s SLAC National Accelerator Laboratory. “At each step of an analysis, there is the danger that prior knowledge guides the way we make adjustments. Blind analyses help us make independent and better decisions.”

    Krause was the main organizer of a recent workshop at KIPAC that looked into how blind analyses could be incorporated into next-generation astronomical surveys that aim to determine more precisely than ever what the universe is made of and how its components have driven cosmic evolution.

    Black boxes and salt

    One outcome of the workshop was a finding that there is no one-size-fits-all approach, says KIPAC postdoc Kyle Story, one of the event organizers. “Blind analyses need to be designed individually for each experiment.”

    The way the blinding is done needs to leave researchers with enough information to allow a meaningful analysis, and it depends on the type of data coming out of a specific experiment.

    A common approach is to base the analysis on only some of the data, excluding the part in which an anomaly is thought to be hiding. The excluded data is said to be in a “black box” or “hidden signal box.”

    Take the search for the Higgs boson. Using data collected with the Large Hadron Collider until the end of 2011, researchers saw hints of a bump as a potential sign of a new particle with a mass of about 125 gigaelectronvolts. So when they looked at new data, they deliberately quarantined the mass range around this bump and focused on the remaining data instead.

    They used that data to make sure they were working with a sufficiently accurate model. Then they “opened the box” and applied that same model to the untouched region. The bump turned out to be the long-sought Higgs particle.

    That worked well for the Higgs researchers. However, as scientists involved with the Large Underground Xenon experiment reported at the workshop, the “black box” method of blind analysis can cause problems if the data you’re expressly not looking at contains rare events crucial to figuring out your model in the first place.

    LUX has recently completed one of the world’s most sensitive searches for WIMPs—hypothetical particles of dark matter, an invisible form of matter that is five times more prevalent than regular matter.

    LUX/Dark matter experiment at SURF

    LUX scientists have done a lot of work to guard LUX against background particles—building the detector in a cleanroom, filling it with thoroughly purified liquid, surrounding it with shielding and installing it under a mile of rock. But a few stray particles make it through nonetheless, and the scientists need to look at all of their data to find and eliminate them.

    For that reason, LUX researchers chose a different blinding approach for their analyses. Instead of using a “black box,” they use a process called “salting.”

    LUX scientists not involved in the most recent LUX analysis added fake events to the data—simulated signals that just look like real ones. Just like the patients in a blind drug trial, the LUX scientists didn’t know whether they were analyzing real or placebo data. Once they completed their analysis, the scientists that did the “salting” revealed which events were false.

    A similar technique was used by LIGO scientists, who eventually made the first detection of extremely tiny ripples in space-time called gravitational waves.

    High-stakes astronomical surveys

    The Blind Analysis workshop at KIPAC focused on future sky surveys that will make unprecedented measurements of dark energy and the Cosmic Microwave Background—observations that will help cosmologists better understand the evolution of our universe.

    CMB per ESA/Planck

    ESA/Planck

    Dark energy is thought to be a force that is causing the universe to expand faster and faster as time goes by. The CMB is a faint microwave glow spread out over the entire sky. It is the oldest light in the universe, left over from the time the cosmos was only 380,000 years old.

    To shed light on the mysterious properties of dark energy, the Dark Energy Science Collaboration is preparing to use data from the Large Synoptic Survey Telescope, which is under construction in Chile. With its unique 3.2-gigapixel camera, LSST will image billions of galaxies, the distribution of which is thought to be strongly influenced by dark energy.


    Dark Energy Camera [DECam], built at FNAL


    NOAO/CTIO Victor M Blanco 4m Telescope which houses the DECam at Cerro Tololo, Chile, housing DECam


    LSST Camera, built at SLAC



    LSST telescope, currently under construction at Cerro Pachón Chile, a 2,682-meter-high mountain in Coquimbo Region, in northern Chile, alongside the existing Gemini South and Southern Astrophysical Research Telescopes.

    “Blinding will help us look at the properties of galaxies picked for this analysis independent of the well-known cosmological implications of preceding studies,” DESC member Krause says. One way the collaboration plans on blinding its members to this prior knowledge is to distort the images of galaxies before they enter the analysis pipeline.

    Not everyone in the scientific community is convinced that blinding is necessary. Blind analyses are more complicated to design than non-blind analyses and take more time to complete. Some scientists participating in blind analyses inevitably spend time looking at fake data, which can feel like a waste.

    Yet others strongly advocate for going blind. KIPAC researcher Aaron Roodman, a particle-physicist-turned-astrophysicist, has been using blinding methods for the past 20 years.

    “Blind analyses have already become pretty standard in the particle physics world,” he says. “They’ll be also crucial for taking bias out of next-generation cosmological surveys, particularly when the stakes are high. We’ll only build one LSST, for example, to provide us with unprecedented views of the sky.”

    See the full article here .

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    Symmetry is a joint Fermilab/SLAC publication.


     
  • richardmitnick 1:56 pm on April 28, 2017 Permalink | Reply
    Tags: , , , , , Large Synoptic Survey Telescope (LSST)   

    From Kavli: “Delving Into the ‘Dark Universe’ with the Large Synoptic Survey Telescope” 

    KavliFoundation

    The Kavli Foundation

    Two astrophysicists and a theoretical physicist discuss how the Large Synoptic Survey Telescope will probe the nature of dark matter and dark energy by taking an unprecedentedly enormous scan of the sky.


    LSST Camera, built at SLAC



    LSST telescope, currently under construction at Cerro Pachón Chile, a 2,682-meter-high mountain in Coquimbo Region, in northern Chile, alongside the existing Gemini South and Southern Astrophysical Research Telescopes.

    AT A MOUNTAINTOP CEREMONY IN CHILE, on April 14th, scientists and diplomats laid the first stone for the Large Synoptic Survey Telescope (LSST). This ambitious international astrophysics project is slated to start scanning the heavens in 2022. When it does, LSST should open up the “dark universe” of dark matter and dark energy—the unseen substance and force, respectively, composing 95 percent of the universe’s mass and energy—as never before.

    The “large” in LSST’s name is a bit of an understatement. The telescope will feature an 8.4-meter diameter mirror and a 3.2 gigapixel camera, the biggest digital camera ever built. The telescope will survey the entire Southern Hemisphere’s sky every few days, hauling in 30 terabytes of data nightly. After just its first month of operations, LSST’s camera will have observed more of the universe than all previous astronomical surveys combined.

    On April 2, 2015, two astrophysicists and a theoretical physicist spoke with The Kavli Foundation about how LSST’s sweeping search for dark matter and dark energy will answer fundamental questions about our universe’s make-up.

    Steven Kahn – is the Director of LSST and the Cassius Lamb Kirk Professor in the Natural Sciences in the Kavli Institute for Particle Astrophysics and Cosmology (KIPAC) at Stanford University.

    Sarah Bridle – is a professor of astrophysics in the Extragalactic Astronomy and Cosmology research group of the Jodrell Bank Center for Astrophysics in the School of Physics and Astronomy at The University of Manchester.

    Hitoshi Murayama – is the Director of the Kavli Institute for the Physics and Mathematics of the Universe (Kavli IPMU) at the University of Tokyo and a professor at the Berkeley Center for Theoretical Physics at the University of California, Berkeley.

    The following is an edited transcript of their roundtable discussion. The participants have been provided the opportunity to amend or edit their remarks.

    THE KAVLI FOUNDATION (TKF): Steven, when the LSST takes its first look at the universe seven years from now, why will this be so exciting to you?

    STEVEN KAHN: In terms of how much light it will collect and its field of view, LSST is about ten times bigger than any other survey telescope either planned or existing. This is important because it will allow us to survey a very large part of the sky relatively quickly and to do many repeated observations of every part of the Southern Hemisphere over ten years. By doing this, the LSST will gather information on an enormous number of galaxies. We’ll detect something like 20 billion galaxies.

    SARAH BRIDLE: That’s a hundred times as many as we’re going to get with the current generation of telescopes, so it’s a huge increase. With the data, we’re going to be able to make a three-dimensional map of the dark matter in the universe using gravitational lensing.

    Gravitational Lensing NASA/ESA

    Gravitational microlensing, S. Liebes, Physical Review B, 133 (1964): 835

    Then we’re going to use that to tell us about how the “clumpiness” of the universe is changing with time, which is going to tell us about dark energy.

    TKF: How does gathering information on billions of galaxies help us learn more about dark energy?

    HITOSHI MURAYAMA: Dark energy is accelerating the expansion of the universe and ripping it apart. The questions we are asking are: Where is the universe going? What is its fate? Is it getting completely ripped apart at some point? Does the universe end? Or does it go forever? Does the universe slow down at some point? To understand these questions, it’s like trying to understand how quickly the population of a given country is aging. You can’t understand the trend of where the country is going just by looking at a small number of people. You have to do a census of the entire population. In a similar way, you need to really look at a vast amount of galaxies so you can understand the trend of where the universe is going. We are taking a cosmic census with LSST.

    2
    A diagram explaining the phenomenon of gravitational lensing. Foreground clumps of dark matter in galaxy clusters gravitationally bend the light from background galaxies on its way to Earth. Note that the image is not to scale. Credit: NASA, ESA, L. Calcada)

    This phenomenon occurs when foreground matter and dark matter contained in galaxy clusters bend the light from background galaxies—sort of like looking through the bottom of a wine glass. Measuring the amount of the distortion of the background galaxies indirectly reveals the amount of dark matter that has clumped together in the foreground object. Measuring the rate of this dark matter clumping across different eras in the universe’s history speaks to how much dark energy is stretching the universe at given times, thus revealing the mysterious, pervasive force’s strength and properties.

    TKF: The main technique the LSST will use to learn more about dark energy will be gravitational lensing. Dark energy is the mysterious, invisible force that is pushing open and shaping the universe. Can you elaborate on why this is important and how will LSST help realize its full potential?

    BRIDLE: It’s extremely difficult to detect the dark energy that seems to be causing our universe to accelerate.


    Dark Energy Camera [DECam], built at FNAL


    NOAO/CTIO Victor M Blanco 4m Telescope which houses the DECam at Cerro Tololo, Chile, housing DECam

    Through gravitational lenses, however, it’s possible by observing how much dark matter is being pulled together by gravity.

    Dark matter cosmic web and the large-scale structure it forms The Millenium Simulation, V. Springel et al

    And by looking at how much this dark matter clumps up early and later on in the universe, we can see how much the universe is being stretched apart at different times. With LSST, there will be a huge increase in the number of galaxies that we can detect and observe. LSST will also let us identify how far away the galaxies are. This is important. If we want to see how fast the universe is clumping together at different times, we need to know at what time and how far away we’re looking.

    KAHN: With LSST, we’re trying to measure the subtle distortion of the appearance of galaxies caused by clumps of dark matter. We do this by looking for correlations in galaxies’ shapes depending on their position with respect to one another. Of course, there’s uncertainty associated with that kind of measurement on the relatively small scales of individual galaxies, and the dominant source of that uncertainty is that galaxies have intrinsic shapes—some are spiral-shaped, some are round, and so on, and we are seeing them at different viewing angles, too. Increasing the number of galaxies with LSST makes doing this a far more statistically powerful and thus precise measurement of the effect of gravitational lensing caused by dark matter and how the clumping of dark matter has changed over the universe’s history.

    LSST will also help address something called cosmic variance. This happens when we’re making comparisons of what we see against a statistical prediction of what an ensemble of possible universes might look like. We only live in one universe, so there’s an inherent error associated with how good those statistical predictions are of what our universe should look like when applied to the largest scales of great fields of galaxies. The only way to try and statistically beat that cosmic variance down is to survey as much of the sky as possible, and that’s the other area where LSST is breaking new ground.

    TKF: Will the gravitational lensing observations by LSST be more accurate than anything before?

    KAHN: One of the reasons I personally got motivated to work on LSST was because of the difficulty in making the sort of weak lensing measurements that Sarah described.

    BRIDLE: Typically, telescopes distort the images of galaxies by more than the gravitational lensing effect we are trying to measure. And in order to learn about dark matter and dark energy from gravitational lensing, we’ve got to not just detect the gravitational lensing signal but measure it to about a one-percent accuracy. So we’ve got to rid of these effects from the optics in the telescope before we can do anything to learn about cosmology.

    KAHN: A lot of the initial work in this field has been plagued by issues associated with the basic telescopes and cameras used. It was hard to separate out the cosmic signals that people were looking for from spurious effects that were introduced by the instrumentation. LSST is actually the first telescope that will have ever been built with the notion of doing weak lensing in mind. We have taken great care to model in detail the whole system, from the telescope to the camera to the atmosphere that we are looking through, to understand the particular issues in the system that could compromise weak lensing measurements. That approach has been a clear driver in how we design the facility and how we calibrate it. It’s been a big motivation for me personally and for the entire LSST team.

    TKF: As LSST reveals the universe’s past, will it also help us predict the future of the universe?

    MURAYAMA: Yes, it will. Because LSST will survey the sky so quickly and repeatedly, it will show how the universe is changing over time. For example, we will be able to see how a supernova changes from one time period to another. This kind of information should prove extremely useful in deciphering the nature of dark energy, for instance.

    KAHN: This is one way LSST will observe changes in the universe and gather information on dark energy beyond gravitational lensing. In fact, the way the acceleration of the universe by dark energy was first discovered in 1998 was through the measurement of what are called Type Ia supernovae.

    Sag A* NASA Chandra X-Ray Observatory 23 July 2014, the supermassive black hole at the center of the Milky Way

    These are exploding stars where we believe we understand the typical intrinsic brightness of the explosion. Therefore, the apparent brightness of a supernova—how faint the supernova appears when we see it—is a clear measure of how far away the object is. That is because objects that are farther away are dimmer than closer objects. By measuring a population of Type Ia supernovae, we can figure out their true distances from us and how those distances have increased over time. Put those two pieces of information together, and that’s a way of determining the expansion rate of the universe.

    This analysis was done for the initial discovery of the accelerating cosmic expansion with a relatively small number of supernovae—just tens. LSST will measure an enormous number of supernovae, something like 250,000 per year. Only a smaller fraction of those will be very well characterized, but that number is still in the tens of thousands per year. That will be very useful for understanding how our universe has evolved.

    TKF: LSST will gather a prodigious amount of data. How will this information be made available to scientists and the public alike for parsing?

    KAHN: Dealing with the enormous size of the data base LSST will produce is a challenge. Over its ten-year run, LSST will generate something like a couple hundred petabytes of data, where a petabyte is 10 to the 15th bytes. That’s more data, by a lot, than everything that’s ever been written in any language in human history.

    The data will be made public to the scientific community largely in the form of catalogs of objects and their properties. But those catalogs can be trillions of lines long. So one of the challenges is not so much how you acquire and store the data, but how do you actually find anything in something that big? It’s the needle in the haystack problem. That’s where there need to be advances because the current techniques that we use to query catalogs, or to say “find me such and such,” they don’t scale very well to this size of data. So a lot of new computer science ideas have to be invoked to make that work.

    ___________________________________________________________________________________

    “With the data, we’re going to be able to make a three-dimensional map of the dark matter in the universe using gravitational lensing. Then we’re going to use that to tell us about how the “clumpiness” of the universe is changing with time, which is going to tell us about dark energy.” –Sarah Bridle
    ___________________________________________________________________________________

    MURAYAMA: One thing that we at Kavli IPMU are pursuing right now is a sort of precursor project to LSST called Hyper Suprime-Cam, using the Subaru Telescope.

    NAOJ Subaru Hyper Suprime Camera

    NAOJ/Subaru Telescope at Mauna Kea Hawaii, USA

    It’s smaller than LSST, but it’s trying to do many of the things that LSST is after, like looking for weak gravitational lensing and trying to understand dark energy. We already are facing the challenge of dealing with a large data set. One aspect we would like to pursue at Kavli IPMU, and of course LSST is already doing it, is to get a lot of people in computer science and statistics involved into this. I believe a new area of statistics will be created by the needs of handling these large data sets. It’s a sort of fusion, the interdisciplinary aspects of this project. It’s a large astronomy survey that will influence other areas of science.

    TKF: Are any “citizen science” projects envisioned for LSST, like Galaxy Zoo, a website where astronomy buffs classify the shapes of millions of galaxies imaged by the Sloan Digital Sky Survey?

    KAHN: Data will be made available right away. So LSST will in some sense bring the universe home to anybody with a personal computer, who can log on and look at any part of the southern hemisphere’s sky at any given time. So there’s a tremendous potential there to engage the public not only in learning about science, but actually in doing science and interacting directly with the universe.

    We have people involved in LSST that are intimately tied into Galaxy Zoo. We’re looking into how to incorporate citizens and crowdsource the science investigations of LSST. One of these investigations is strong gravitational lensing. Sarah has talked about weak gravitational lensing, which is a very subtle distortion to the appearance of the background galaxies. But it turns out if you put a galaxy right behind a concentration of dark matter found in a massive foreground galaxy cluster, then the distortions can get very significant. You can actually see multiple images of the background galaxy in a single image, bent all the way around the foreground galaxy cluster. The detection of those strong gravitational lenses and the analysis of the light patterns you see within them also yields complementary scientific information about cosmological fundamental parameters. But it requires sort of recognizing what is in fact a strong gravitational lensing event, as well as modeling the distribution of dark matter that gives rise to the strength of that particular lensing. Colleagues of Hitoshi and myself have already created a tool to help with this effort, called SpaceWarps (www.spacewarps.org). The tool lets the public look for strong gravitational lenses using data from the Sloan Digital Sky Survey and to play around with dark matter modeling to see if they can get something that looks like the real data.

    ___________________________________________________________________________

    “Over its ten-year run, LSST will generate something like a couple hundred petabytes of data, where a petabyte is 10 to the 15th bytes. That’s more data, by a lot, than everything that’s ever been written in any language in human history.” –Steven Kahn
    ___________________________________________________________________________

    MURAYAMA: This has been incredibly successful. Scientists have developed computer programs to automatically look for these strongly lensed galaxies, but even an algorithm written by the best scientists can still miss some of these strong gravitationally lensed objects. Regular citizens, however, often manage to find some candidates for the strongly lensed galaxies that the computer algorithm has missed. Not only will this be great fun for people to get involved, it can even help the science as well, especially with a project as large as LSST.

    TKF: In the hunt for dark energy’s signature on the cosmos, LSST is just one of many current and planned efforts. Sarah, how will LSST observations tie in with the Dark Energy Survey you’re working on, and Hitoshi, with will LSST complement the Hyper Suprime-Cam?

    BRIDLE: So the Dark Energy Survey is going to image one-eighth of the whole sky and have 300 million galaxy images. About two years of data have been taken so far, with about three more years to go. We’ll be doing maps of dark matter and measurements of dark energy. The preparation for LSST that we are doing via DES will be essential.

    MURAYAMA: Hyper Suprime-Cam is similar to the Dark Energy Survey. It’s a nearly billion pixel camera looking for nearly 10 million galaxies. Following up on the Hyper Suprime-Cam imaging surveys, we would like to measure what we call spectra from a couple million galaxies.

    KAHN: The measurement of spectra as an addition to imaging tells us not only about the structure of matter in the universe but also how much the matter is moving with respect to the overall, accelerating cosmic expansion due to dark energy. Spectra are an additional, very important piece of information in constraining cosmological models.

    MURAYAMA: We will identify spectra with an instrument called the Prime Focus Spectrograph, which is scheduled to start operations in 2017 also on the Subaru telescope.

    NAOJ Subaru Prime Focus Spectrograph

    We will do very deep exposures to get the spectra on some of these interesting objects, such as galaxies where lensing is taking place and supernovae, which will also allow us to do much more precise measurements on dark energy.

    3
    This image from a pilot project, the Deep Lens Survey (DLS), offers up an example of what the sky will look like when observed by LSST. The images from LSST will have twice DLS’ depth and resolution, while also covering 50,000 times the area of this particular image, and in six different optical colors. Credit: Deep Lens Survey / UC Davis / NOAO)

    Like the Hyper Suprime-Cam, LSST can only do imaging. So I’m hoping when LSST comes online in the 2020s, we will already have the Prime Focus Spectrograph operational, and we will be able to help each other. LSST’s huge amount of data will contain many interesting objects we would like to study with this Prime Focus Spectrograph.

    KAHN: All these dark matter and dark energy telescope projects are very complementary to each other. It’s because of the scientific importance of these really fundamental pressing questions—what is the nature of dark matter and dark energy?—that the various different funding institutions around the world have been eager to invest in such an array of different complementary projects. I think that’s great, and it just shows how important this general problem is.

    TKF: Hitoshi, you mentioned earlier the interdisciplinary approach fostered by LSST and projects like it, and you’ve spoken before about how having different scientific disciplines and perspectives together leads to breakthrough thinking—a major goal of Kavli IPMU. Your primary expertise is in particle physics, but you work on many other areas of physics. Could you describe how observations of the very biggest scales of the dark universe with LSST will inform work on the very smallest, subatomic scales, and vice versa?

    MURAYAMA: It’s really incredible to think about this point. The biggest thing we can observe in the universe has to have something to do with the smallest things we can think of and all the matter we see around us.

    BRIDLE: It is amazing that you can look at the largest scales and find out about the smallest things.

    MURAYAMA: For more than a hundred years, particle physicists have been trying to understand what everything around us is made of. We made huge progress by building a theory called the standard model of particle physics in the 20th century, which is really a milestone of science. Discovering the Higgs boson at the Large Hadron Collider at CERN in 2012 really nailed that the standard model is the right theory about the origin of everything around us. But it turns out that what we see around us is actually making up only five percent of the universe.

    CERN CMS Higgs Event

    CERN ATLAS Higgs Event

    The Standard Model of elementary particles (more schematic depiction), with the three generations of matter, gauge bosons in the fourth column, and the Higgs boson in the fifth.

    So there is this feeling among particle physicists of “what have we been doing for a hundred years?” We only have five percent of the universe! We still need to understand the remaining 95 percent of the universe, which is dark matter and dark energy. It’s a huge problem and we have no idea what they are really.

    ______________________________________________________________________________________

    “The biggest thing we can observe in the universe has to have something to do with the smallest things we can think of.” –Hitoshi Murayama
    ______________________________________________________________________________________

    A way I explain what dark matter is: It’s the mother from whom we got separated at birth. What I mean by this is without dark matter, there’s no structure to the universe—no galaxies, no stars—and we wouldn’t be here. Dark matter, like a mother, is the reason we exist, but we haven’t met her and have never managed to thank her. So that’s the reason why we would like to know who she is, how she came to exist and how she shaped us. That’s the connection between the science of looking for the fundamental constituents of the universe, which is namely what particle physicists are after, and this largest scale of observation done with LSST.

    TKF: Given LSST’s vast vista on the Universe, it is frankly expected that the project will turn up the unexpected. Any ideas or speculations on what tracking such a huge portion of the universe might newly reveal?

    KAHN: That’s sort of like asking, “what are the unknown unknowns?” [laughter]

    TKF: Yes—good luck figuring those out!

    KAHN: Let me just say, one of the great things about astrophysics is that we have explicit theoretical predictions we’re trying to test out by taking measurements of the universe. That approach is more akin to many other areas of experimental physics, like searching for the Higgs boson with the Large Hadron Collider, as Hitoshi mentioned earlier.

    CERN/LHC Map


    CERN LHC Tunnel



    LHC at CERN

    But there’s also this wonderful history in astronomy that every time we build a bigger and better facility, we always find all kinds of new things we never envisioned.

    If you go back—unfortunately I’m old enough to remember these days—to the period before the launch of the Hubble Space Telescope, it’s interesting to see what people had thought were going to be the most exciting things to do with Hubble. Many of those things were done and they were definitely exciting. But I think what many people felt was the most exciting was the stuff we didn’t even think to ask about, like the discovery of dark energy Hubble helped make. So I think a lot of us have expectations of similar kinds of discoveries for facilities like LSST. We will make the measurement we’re intending to make, but there will be a whole bunch of other exciting stuff that we never even dreamed of that’ll come for free on top.

    BRIDLE: I’m a cosmologist and I’m very excited for what LSST is going to do for cosmology, but I’m even more excited that it’s going to be taking very, very short 15-second exposures of the sky. LSST is going to be able to discover all these changing, fleeting objects like supernovae that Hitoshi talked about, but it’s a whole new phase of discovery. It’s inevitable we’re going to discover a whole load of new stuff that we’ve never even thought of.

    MURAYAMA: I’m sure there will be surprises!

    See the full article here .

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    Stem Education Coalition
    The Kavli Foundation, based in Oxnard, California, is dedicated to the goals of advancing science for the benefit of humanity and promoting increased public understanding and support for scientists and their work.

    The Foundation’s mission is implemented through an international program of research institutes, professorships, and symposia in the fields of astrophysics, nanoscience, neuroscience, and theoretical physics as well as prizes in the fields of astrophysics, nanoscience, and neuroscience.

     
  • richardmitnick 12:36 pm on April 6, 2017 Permalink | Reply
    Tags: , , , , Gemini Observatory Octocam, Large Synoptic Survey Telescope (LSST)   

    From Gemini Observatory: “OCTOCAM Looks Toward a New Era of Discovery” 

    NOAO

    Gemini Observatory
    Gemini Observatory

    April 5, 2017
    Science/Technical Contacts:

    Stephen Goodsell
    Gemini Program Manager
    Durham University, Durham, UK
    Email: sgoodsell”at”gemini.edu
    Cell: +44 7539256513

    Scot Kleinman
    Gemini Head of Development
    Gemini Observatory, Hilo, Hawai‘i
    Email: kleinman”at”gemini.edu
    Office: 808 074-2618

    Media Contact:

    Peter Michaud
    Public Information and Outreach Manager
    Gemini Observatory, Hilo, Hawai‘i
    Email: pmichaud”at”gemini.edu
    Desk: 808 974-2510
    Cell: 808 936-6643

    1
    OCTOCAM’s near-infrared optical bench. The near-infrared section is cryogenically cooled in a vacuum to operate at a temperature below 80 Kelvin.

    2
    OCTOCAM’s visible optical bench. The visible section is kept at about the temperature of the outside telescope environment.

    Gemini Observatory announces the development of a major new facility-class broadband optical and near-infrared imager and spectrograph named OCTOCAM.

    “OCTOCAM provides Gemini with a unique capability as we look ahead to the Large Synoptic Survey Telescope era,” says Stephen Goodsell who manages the instrument program for Gemini. “The instrument will be able to rapidly acquire transient objects and simultaneously obtain eight images or spectral bands from each target,” according to Goodsell. “This is important because it provides a much greater level of information and detail, which will undoubtedly lead to transformational scientific discoveries.”

    The power of the instrument comes from its ability to simultaneously observe over an extremely wide swath of the optical and infrared spectrum. It is expected that when the instrument begins commissioning and observations in 2022 it will serve as an ideal complement to the discoveries made with the Large Synoptic Survey Telescope (LSST) by providing rapid follow-up capabilities.


    LSST Camera, built at SLAC



    LSST telescope, currently under construction at Cerro Pachón Chile, a 2,682-meter-high mountain in Coquimbo Region, in northern Chile, alongside the existing Gemini South and Southern Astrophysical Research Telescopes.

    Once completed the instrument is slated for installation on the 8-meter Gemini South telescope which is located adjacent to the current construction site of the LSST on Cerro Pachón in Chile.

    “Two core tenets of Gemini’s future vision are to lead as a premier facility for taking advantage of the upcoming discoveries from the LSST; while offering broad, flexible capabilities that enable a wide-range of individual PI-driven science,” says Scot Kleinman, Associate Director of Development at Gemini. “OCTOCAM, with its eight simultaneous channels, including both imaging and spectroscopic capabilities, moves Gemini a giant step closer to this vision. We are thrilled to make this transformative instrument available to our community in early 2022.”

    Chris Davis, Program Officer at the U.S. National Science Foundation (NSF, which also funds the LSST), notes that because Gemini has international funding participants that include the U.S., Canada, Brazil, Argentina, and Chile, this project spans the globe. “All of the Gemini participants contribute to the development of instruments like OCTOCAM,” says Davis. However, he adds, “OCTOCAM really captures the spirit of international cooperation with the global network of researchers that are designing and building this instrument.”

    In late March the Association of Universities for Research in Astronomy (AURA, which operates Gemini on behalf of the NSF) and the Southwest Research Institute (SwRI) signed a contract to build and commission the instrument. With the contract signed work began immediately on the conceptual design of the instrument. Please see SwRI press release here.

    “Using eight state-of-the-art detectors, OCTOCAM will simultaneously observe visible and invisible light spectra almost instantaneously, in tens of milliseconds,” said Dr. Peter Roming, a staff scientist at SwRI who will serve as project manager and co-principal investigator. SwRI will oversee systems engineering, providing detectors, electronics, and software development for this refrigerator-sized, ground-based apparatus. The Institute will also lead the integration and testing of the device.

    “It’s really exciting to be working on an 8-meter class instrument that will be used to observe the whole Universe, from the oldest stars to nearby exoplanets,” Roming said. “The imaging, spectral analysis, and temporal resolution combined with exceptional sensitivity make OCTOCAM a unique, unparalleled instrument.”

    “OCTOCAM has been designed to revolutionize the research in many fields of astrophysics. To achieve this, a large, international group of scientists determined the key science questions to be addressed in the coming decade and those were used subsequently to define the technical characteristics that will allow OCTOCAM to answer them,” says Antonio de Ugarte Postigo, scientist at the Instituto de Astrofísica of Andalucía (IAA-CSIC) in Granada, Spain and principal investigator of the project.

    “We look forward to a work that will involve the full scientific community of Gemini. OCTOCAM will open a new window of research by occupying a region in the spectral coverage-spectral resolution-time resolution diagram not covered by any other instrument in the world,” says Christina Thöne, scientist at IAA, Granada and Deputy Project Manager of OCTOCAM.

    “I am very excited about the science that we will be able to do with OCTOCAM,” said Dr. Alexander van der Horst, an assistant professor of astrophysics at the George Washington University in Washington, DC, and the project scientist for OCTOCAM. “The capabilities of OCTOCAM make it a unique instrument, and it will provide a wealth of information on a very broad range of objects, from rocks of ice in our own solar system to the most massive stars exploding at the edge of our Universe.”

    Please visit OCTOCAM page for the list of team members and more.

    See the full article here .

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    Gemini/North telescope at Mauna Kea, Hawaii, USA
    Gemini/North telescope at Mauna Kea, Hawaii, USA

    Gemini South
    Gemini South telescope, Cerro Tololo Inter-American Observatory (CTIO) campus near La Serena, Chile

    AURA Icon

    Gemini’s mission is to advance our knowledge of the Universe by providing the international Gemini Community with forefront access to the entire sky.

    The Gemini Observatory is an international collaboration with two identical 8-meter telescopes. The Frederick C. Gillett Gemini Telescope is located on Mauna Kea, Hawai’i (Gemini North) and the other telescope on Cerro Pachón in central Chile (Gemini South); together the twin telescopes provide full coverage over both hemispheres of the sky. The telescopes incorporate technologies that allow large, relatively thin mirrors, under active control, to collect and focus both visible and infrared radiation from space.

    The Gemini Observatory provides the astronomical communities in six partner countries with state-of-the-art astronomical facilities that allocate observing time in proportion to each country’s contribution. In addition to financial support, each country also contributes significant scientific and technical resources. The national research agencies that form the Gemini partnership include: the US National Science Foundation (NSF), the Canadian National Research Council (NRC), the Chilean Comisión Nacional de Investigación Cientifica y Tecnológica (CONICYT), the Australian Research Council (ARC), the Argentinean Ministerio de Ciencia, Tecnología e Innovación Productiva, and the Brazilian Ministério da Ciência, Tecnologia e Inovação. The observatory is managed by the Association of Universities for Research in Astronomy, Inc. (AURA) under a cooperative agreement with the NSF. The NSF also serves as the executive agency for the international partnership.

     
  • richardmitnick 10:27 pm on March 3, 2017 Permalink | Reply
    Tags: , , , , Large Synoptic Survey Telescope (LSST), ,   

    From Universe Today: “Rise of the Super Telescopes”: LSST 

    universe-today

    Universe Today

    3 Mar , 2017
    Evan Gough

    LSST
    LSST/Camera, built at SLAC
    LSST/Camera, built at SLAC
    LSST Interior
    LSST telescope, currently under construction at Cerro Pachón Chile, a 2,682-meter-high mountain in Coquimbo Region, in northern Chile, alongside the existing Gemini South and Southern Astrophysical Research Telescopes.
    LSST telescope, currently under construction at Cerro Pachón Chile, a 2,682-meter-high mountain in Coquimbo Region, in northern Chile, alongside the existing Gemini South and Southern Astrophysical Research Telescopes

    Gemini South telescope, Cerro Tololo Inter-American Observatory (CTIO) campus near La Serena, Chile
    Gemini South telescope, Cerro Tololo Inter-American Observatory (CTIO) campus near La Serena, Chile

    NOAO/ Southern Astrophysical Research Telescope (SOAR)telescope situated on Cerro Pachón - IV Región - Chile, at 2,700 meters (8,775 feet)
    NOAO/ Southern Astrophysical Research Telescope (SOAR)telescope situated on Cerro Pachón – IV Región – Chile, at 2,700 meters (8,775 feet)

    While the world’s other Super Telescopes rely on huge mirrors to do their work, the LSST is different. It’s a huge panoramic camera that will create an enormous moving image of the Universe. And its work will be guided by three words: wide, deep, and fast.

    While other telescopes capture static images, the LSST will capture richly detailed images of the entire available night sky, over and over. This will allow astronomers to basically “watch” the movement of objects in the sky, night after night. And the imagery will be available to anyone.

    The LSST is being built by a group of institutions in the US, and even got some money from Bill Gates. It will be situated atop Cerro Pachon, a peak in Northern Chile. The Gemini South and Southern Astrophysical Research Telescopes are also situated there.

    See the full article here .

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  • richardmitnick 2:28 pm on January 14, 2017 Permalink | Reply
    Tags: , , , , Large Synoptic Survey Telescope (LSST), , Twinkles   

    From Symmetry: “Twinkle, twinkle, little supernova” 

    Symmetry Mag
    Symmetry

    01/12/17
    Ricarda Laasch

    1
    Phil Marshall, SLAC

    Using Twinkles, the new simulation of images of our night sky, scientists get ready for a gigantic cosmological survey unlike any before.

    Almost every worthwhile performance is preceded by a rehearsal, and scientific performances are no exception. Engineers test a car’s airbag deployment using crash test dummies before incorporating them into the newest model. Space scientists fire a rocket booster in a test environment before attaching it to a spacecraft in flight.

    One of the newest “training grounds” for astrophysicists is called Twinkles. The Twinkles dataset, which has not yet been released, consists of thousands of simulated, highly realistic images of the night sky, full of supernovae and quasars. The simulated-image database will help scientists rehearse a future giant cosmological survey called LSST.

    LSST
    LSST/Camera, built at SLAC
    LSST/Camera, built at SLAC
    LSST Interior
    LSST telescope, currently under construction at Cerro Pachón Chile, a 2,682-meter-high mountain in Coquimbo Region, in northern Chile, alongside the existing Gemini South and Southern Astrophysical Research Telescopes.
    LSST telescope, currently under construction at Cerro Pachón Chile, a 2,682-meter-high mountain in Coquimbo Region, in northern Chile, alongside the existing Gemini South and Southern Astrophysical Research Telescopes.

    LSST, short for the Large Synoptic Survey Telescope, is under construction in Chile and will conduct a 10-year survey of our universe, covering the entire southern sky once a year. Scientists will use LSST images to explore our galaxy to learn more about supernovae and to shine a light on the mysterious dark energy that is responsible for the expansion of our universe.

    It’s a tall order, and it needs a well prepared team. Scientists designed LSST using simulations and predictions for its scientific capabilities. But Twinkles’ thousands of images will give them an even better chance to see how accurately their LSST analysis tools can measure the changing brightness of supernovae and quasars. That’s the advantage of using simulated data. Scientists don’t know about all the objects in the sky above our heads, but they do know their simulated sky— there, they already know the answers. If the analysis tools make a calculation error, they’ll see it.

    The findings will be a critical addition to LSST’s measurements of certain cosmological parameters, where a small deviation can have a huge impact on the outcome.

    “We want to understand the whole path of the light: From other galaxies through space to our solar system and our planet, then through our atmosphere to the telescope – and from there through our data-taking system and image processing,” says Phil Marshall, a scientist at the US Department of Energy’s SLAC National Accelerator Laboratory who leads the Twinkles project. “Twinkles is our way to go all the way back and study the whole picture instead of one single aspect.”

    Scientists simulate the images as realistically as possible to figure out if some systematic errors add up or intertwine with each other. If they do, it could create unforeseen problems, and scientists of course want to deal with them before LSST starts.

    Twinkles also lets scientists practice sorting out a different kind of problem: A large collaboration spread across the whole globe that will perform numerous scientific searches simultaneously on the same massive amounts of data.

    Richard Dubois, senior scientist at SLAC and co-leader of the software infrastructure team, works with his team of computing experts to create methods and plans to deal with the data coherently across the whole collaboration and advise the scientists to choose specific tools to make their life easier.

    “Chaos is a real danger; so we need to keep it in check,” Dubois says. “So with Twinkles, we test software solutions and databases that help us to keep our heads above water.”

    The first test analysis using Twinkles images will start toward the end of the year. During the first go, scientists extract type 1a supernovae and quasars and learn how to interpret the automated LSST measurements.

    “We hid both types of objects in the Twinkles data,” Marshall says. “Now we can see whether they look the way they’re supposed to.”

    LSST will start up in 2022, and the first LSST data will be released at the end of 2023.

    “High accuracy cosmology will be hard,” Marshall says. “So we want to be ready to start learning more about our universe right away!”

    See the full article here .

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    Symmetry is a joint Fermilab/SLAC publication.


     
  • richardmitnick 2:40 pm on November 25, 2016 Permalink | Reply
    Tags: , , GridPP, Large Synoptic Survey Telescope (LSST), Shear brilliance: computing tackles the mystery of the dark universe,   

    From U Manchester: “Shear brilliance: computing tackles the mystery of the dark universe” 

    U Manchester bloc

    University of Manchester

    24 November 2016
    No writer credit found

    Scientists from The University of Manchester working on a revolutionary telescope project have harnessed the power of distributed computing from the UK’s GridPP collaboration to tackle one of the Universe’s biggest mysteries – the nature of dark matter and dark energy.

    Researchers at The University of Manchester have used resources provided by GridPP – who represent the UK’s contribution to the computing grid used to find the Higgs boson at CERN – to run image processing and machine learning algorithms on thousands of images of galaxies from the international Dark Energy Survey.

    Dark Energy Icon

    The Manchester team are part of the collaborative project to build the Large Synoptic Survey Telescope (LSST), a new kind of telescope currently under construction in Chile and designed to conduct a 10-year survey of the dynamic Universe. LSST will be able to map the entire visible sky.

    LSST/Camera, built at SLAC
    LSST/Camera, built at SLAC

    LSST Interior
    LSST telescope, currently under construction at Cerro Pachón Chile
    LSST telescope, currently under construction at Cerro Pachón Chile

    In preparation to the LSST starting its revolutionary scanning, a pilot research project has helped researchers detect and map out the cosmic shear seen across the night sky, one of the tell-tale signs of the dark matter and dark energy thought to make up some 95 per cent of what we see in the Universe. This in turn will help prepare for the analysis of the expected 200 petabytes of data the LSST will collect when it starts operating in 2023.

    The pilot research team based at The Manchester of University was led by Dr Joe Zuntz, a cosmologist originally at Manchester’s Jodrell Bank Observatory and now a researcher at the Royal Observatory in Edinburgh.

    “Our overall aim is to tackle the mystery of the dark universe – and this pilot project has been hugely significant. When the LSST is fully operating researchers will face a galactic data deluge – and our work will prepare us for the analytical challenge ahead.”
    Sarah Bridle, Professor of Astrophysics

    Dr George Beckett, the LSST-UK Science Centre Project Manager based at The University of Edinburgh, added: “The pilot has been a great success. Having completed the work, Joe and his colleagues are able to carry out shear analysis on vast image sets much faster than was previously the case. Thanks are due to the members of the GridPP community for their assistance and support throughout.”

    The LSST will produce images of galaxies in a wide variety of frequency bands of the visible electromagnetic spectrum, with each image giving different information about the galaxy’s nature and history. In times gone by, the measurements needed to determine properties like cosmic shear might have been done by hand, or at least with human-supervised computer processing.

    With the billions of galaxies expected to be observed by LSST, such approaches are unfeasible. Specialised image processing and machine learning software (Zuntz 2013) has therefore been developed for use with galaxy images from telescopes like LSST and its predecessors. This can be used to produce cosmic shear maps like those shown in the figure below. The challenge then becomes one of processing and managing the data for hundreds of thousands of galaxies and extracting scientific results required by LSST researchers and the wider astrophysics community.

    As each galaxy is essentially independent of other galaxies in the catalogue, the image processing workflow itself is highly parallelisable. This makes it an ideal problem to tackle with the kind of High-Throughput Computing (HTP) resources and infrastructure offered by GridPP. In many ways, the data from CERN’s Large Hadron Collider particle collision events is like that produced by a digital camera (indeed, pixel-based detectors are used near the interaction points) – and GridPP regularly processes billions of such events as part of the Worldwide LHC Computing Grid (WLCG).

    A pilot exercise, led by Dr Joe Zuntz while at The University of Manchester and supported by one of the longest serving and most experienced GridPP experts, Senior System Administrator Alessandra Forti, saw the porting of the image analysis workflow to GridPP’s distributed computing infrastructure. Data from the Dark Energy Survey (DES) was used for the pilot.

    After transferring this data from the US to GridPP Storage Elements, and enabling the LSST Virtual Organisation on a number of GridPP Tier-2 sites, the IM3SHAPE analysis software package (Zuntz, 2013) was tested on local, grid-friendly client machines to ensure smooth running on the grid. Analysis jobs were then submitted and managed using the Ganga software suite, which is able to coordinate the thousands of individual analyses associated with each batch of galaxies. Initial runs were submitted using Ganga to local grid sites, but the pilot progressed to submission to multiple sites via the GridPP DIRAC (Distributed Infrastructure with Remote Agent Control) service. The flexibility of Ganga allows both types of submission, which made the transition from local to distributed running significantly easier.

    By the end of pilot, Dr Zuntz was able to run the image processing workflow on multiple GridPP sites, regularly submitting thousands of analysis jobs on DES images.

    See the full article here .

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    U Manchester campus

    The University of Manchester (UoM) is a public research university in the city of Manchester, England, formed in 2004 by the merger of the University of Manchester Institute of Science and Technology (renamed in 1966, est. 1956 as Manchester College of Science and Technology) which had its ultimate origins in the Mechanics’ Institute established in the city in 1824 and the Victoria University of Manchester founded by charter in 1904 after the dissolution of the federal Victoria University (which also had members in Leeds and Liverpool), but originating in Owens College, founded in Manchester in 1851. The University of Manchester is regarded as a red brick university, and was a product of the civic university movement of the late 19th century. It formed a constituent part of the federal Victoria University between 1880, when it received its royal charter, and 1903–1904, when it was dissolved.

    The University of Manchester is ranked 33rd in the world by QS World University Rankings 2015-16. In the 2015 Academic Ranking of World Universities, Manchester is ranked 41st in the world and 5th in the UK. In an employability ranking published by Emerging in 2015, where CEOs and chairmen were asked to select the top universities which they recruited from, Manchester placed 24th in the world and 5th nationally. The Global Employability University Ranking conducted by THE places Manchester at 27th world-wide and 10th in Europe, ahead of academic powerhouses such as Cornell, UPenn and LSE. It is ranked joint 56th in the world and 18th in Europe in the 2015-16 Times Higher Education World University Rankings. In the 2014 Research Excellence Framework, Manchester came fifth in terms of research power and seventeenth for grade point average quality when including specialist institutions. More students try to gain entry to the University of Manchester than to any other university in the country, with more than 55,000 applications for undergraduate courses in 2014 resulting in 6.5 applicants for every place available. According to the 2015 High Fliers Report, Manchester is the most targeted university by the largest number of leading graduate employers in the UK.

    The university owns and operates major cultural assets such as the Manchester Museum, Whitworth Art Gallery, John Rylands Library and Jodrell Bank Observatory which includes the Grade I listed Lovell Telescope.

     
  • richardmitnick 9:32 am on October 26, 2016 Permalink | Reply
    Tags: , Large Synoptic Survey Telescope (LSST), Scheduling algorithm for LSST   

    From Harvard John A Paulson School of Engineering and Applied Sciences: “Eye on the sky” 

    Harvard School of Engineering and Applied Sciences
    harvard John A Paulson School of Engineering and Applied Sciences

    October 26, 2016
    Adam Zewe

    Student uses computer science to chart a course for massive telescope

    When it begins operating in 2022, the $500 million Large Synoptic Survey Telescope (LSST) will capture some of the sharpest night sky images ever produced, giving scientists an unprecedented view of near-Earth asteroids, supernovae, and the Milky Way galaxy.

    But the telescope, under construction atop a peak is Chile’s northern Andes, also presents an unprecedented challenge for astrophysicists—it will require a complicated scheduling algorithm to determine where to point the telescope as it traces the sky. To Harvard student Daniel Rothchild, that sounded like a puzzle he could solve.

    “This is not a well-studied problem in astrophysics because there has never been a telescope that behaved like this,” said Rothchild, A.B. ’17, a physics concentrator who is pursing a secondary in computer science at the John A. Paulson School of Engineering and Applied Sciences. “But scheduling is a well-studied problem in computer science. It is very important that the scheduler be effective, or the telescope is not going to be looking at the places that will yield the best data.”

    Working with Christopher Stubbs, Samuel C. Moncher Professor of Physics and Astronomy, who is a contributor to the LSST project, Rothchild launched an independent research project to develop a scheduling algorithm that would be effective in this unique situation.

    LSST/Camera, built at SLAC
    LSST/Camera, built at SLAC
    LSST Interior
    LSST telescope, currently under construction at Cerro Pachón Chile
    LSST telescope, currently under construction at Cerro Pachón Chile

    The LSST, which will image the entire night sky every three days, will stop at each point for 30 seconds before moving onto a new field. Longer calculation time leads to a much more complicated algorithm and that could easily bog down the telescope’s progress. The algorithm must also overcome the challenge of determining the “best” place for the telescope to look, when there are literally 10 billion possibilities.

    “How do you decide if Milky Way astronomy is more important than asteroid science on this particular 30-second exposure?” Rothchild asked. “It’s very difficult for scientists to say, here’s an exact quantification of how important these different areas are.”

    Rather than using machine-learning or mathematical merit functions to determine the ideal next field, Rothchild is writing code that will give the telescope a baseline optimal path to follow, along with instructions for how to respond when faced with adverse weather and unexpected downtime.

    Programming a set path for the entire 10-year span of the project allows scientists to explicitly optimize global properties of the telescope’s data, instead of hoping the merit functions or machine-learning algorithms will perform those optimizations themselves, he said. It also eliminates the headaches of trying to determine why the computer pointed the telescope at a certain location, or troubleshooting a machine-learning algorithm that seems to be aiming the telescope far off the best course.

    “There are certain astronomical elements that are fixed, even 10 years out. We know the moon will be moving a certain way and the stars will appear in specific patterns and locations, and we also know the meridian is generally the best place to point the telescope because there is the least amount of air overhead,” he said. “By programming these considerations into the scheduler explicitly, I hope to create an algorithm that will produce better schedules than those produced with existing methods.”

    His code lays out a path for the telescope to follow using a combination of astronomical data and meteorological predictions. Rothchild’s method involves much faster calculations than other scheduler algorithms because there are no machine-learning elements.

    Several other researchers are working on schedulers, and all have taken a slightly different approach. Once the telescope hardware is complete, the LSST leadership team will test each scheduler and select the one to use.

    Though he still has six years to wait before the LSST has its eye on the sky, Rothchild is excited for the opportunity to contribute to such a significant astrophysics project.

    “The LSST will produce about 15 terabytes of data each night for 10 years. By comparison, the Hubble telescope produces 10 terabytes of data in one year,” he said. “This project is going to enable scientists to take precision measurements of the universe in an unprecedented way. It is very cool to be a part of that.”

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    Currently under construction in Chile, the LSST will incorporate the world’s largest digital camera. (Photo credit: LSST.)

    See the full article here .

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    Stem Education Coalition

    Through research and scholarship, the Harvard School of Engineering and Applied Sciences (SEAS) will create collaborative bridges across Harvard and educate the next generation of global leaders. By harnessing the power of engineering and applied sciences we will address the greatest challenges facing our society.

    Specifically, that means that SEAS will provide to all Harvard College students an introduction to and familiarity with engineering and technology as this is essential knowledge in the 21st century.

    Moreover, our concentrators will be immersed in the liberal arts environment and be able to understand the societal context for their problem solving, capable of working seamlessly withothers, including those in the arts, the sciences, and the professional schools. They will focus on the fundamental engineering and applied science disciplines for the 21st century; as we will not teach legacy 20th century engineering disciplines.

    Instead, our curriculum will be rigorous but inviting to students, and be infused with active learning, interdisciplinary research, entrepreneurship and engineering design experiences. For our concentrators and graduate students, we will educate “T-shaped” individuals – with depth in one discipline but capable of working seamlessly with others, including arts, humanities, natural science and social science.

    To address current and future societal challenges, knowledge from fundamental science, art, and the humanities must all be linked through the application of engineering principles with the professions of law, medicine, public policy, design and business practice.

    In other words, solving important issues requires a multidisciplinary approach.

    With the combined strengths of SEAS, the Faculty of Arts and Sciences, and the professional schools, Harvard is ideally positioned to both broadly educate the next generation of leaders who understand the complexities of technology and society and to use its intellectual resources and innovative thinking to meet the challenges of the 21st century.

    Ultimately, we will provide to our graduates a rigorous quantitative liberal arts education that is an excellent launching point for any career and profession.

     
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