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  • richardmitnick 1:45 pm on June 25, 2015 Permalink | Reply
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    From Symmetry: “Exploring dark energy with robots” 

    Symmetry

    June 25, 2015
    Glenn Roberts Jr.

    The Dark Energy Spectroscopic Instrument will produce a 3-D space map using a ‘hive’ of robots.

    1
    Courtesy of NOAO

    Five thousand pencil-shaped robots, densely nested in a metal hive, whir to life with a precise, dizzying choreography. Small U-shaped heads swivel into a new arrangement in a matter of seconds.

    This preprogrammed routine will play out about four times per hour every night at the Dark Energy Spectroscopic Instrument. The robots of DESI will be used to produce a 3-D map of one-third of the sky. This will help DESI fulfill its primary mission of investigating dark energy, a mysterious force thought to be causing the acceleration of the expansion of the universe.

    DESI Dark Energy Spectroscopic Instrument
    DESI

    The tiny robots will be arranged in 10 wedge-shaped metal “petals” that together form a cylinder about 2.6 feet across. They will maneuver the ends of fiber-optic cables to point at sets of galaxies and other bright objects in the universe. DESI will determine their distance from Earth based on the light they emit.

    DESI’s robots are in development at Lawrence Berkeley National Laboratory, the lead in the DESI collaboration, and at the University of Michigan.

    2
    Courtesy of: DESI collaboration

    The robots—each about 8 millimeters wide in their main section and 8 inches long—will be custom-built around commercially available motors measuring just 4 millimeters in diameter. This type of precision motor, at this size, became commercially available in 2013 and is now manufactured by three companies. The motors have found use in medical devices such as insulin pumps, surgical robots and diagnostic tools.

    At DESI, the robots will automate what was formerly a painstaking manual process used at previous experiments. At the Baryon Oscillation Spectroscopic Survey, or BOSS, which began in 2009, technicians must plug 1000 fibers by hand several times each day into drilled metal plates, like operators plugging cables into old-fashioned telephone switchboards.

    “DESI is exciting because all of that work will be done robotically,” says Risa Wechsler, a co-spokesperson for DESI and an associate professor of the Kavli Institute for Particle Astrophysics and Cosmology, a joint institute of Stanford University and SLAC National Accelerator Laboratory. Using the robots, DESI will be able to redirect all of its 5000 fibers in an elaborate dance in less than 30 seconds (see video).

    “DESI definitely represents a new era,” Wechsler says.

    In addition to precisely measuring the color of light emitted by space objects, DESI will also measure how the clustering of galaxies and quasars, which are very distant and bright objects, has evolved over time. It will calculate the distance for up to 25 million space objects, compared to the fewer than 2 million objects examined by BOSS.

    The robots are designed to both collect and transmit light. After each repositioning of fibers, a special camera measures the alignment of each robot’s fiber-optic cable within thousandths of a millimeter. If the robots are misaligned, they are automatically individually repositioned to correct the error.

    Each robot has its own electronics board and can shut off and turn on independently, says Joe Silber, an engineer at Berkeley Lab who manages the system that includes the robotic array.

    In seven successive generations of prototype designs, Silber has worked to streamline and simplify the robots, trimming down their design from 60 parts to just 18. “It took a long time to really understand how to make these things as cheap and simple as possible,” he says. “We were trying not to get too clever with them.”

    The plan is for DESI to begin a 5-year run at Kitt Peak National Observatory near Tucson, Arizona, in 2019. Berkeley and Michigan scientists plan to build a test batch of 500 robots early next year, and to build the rest in 2017 and 2018.

    See the full article here.

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    Symmetry is a joint Fermilab/SLAC publication.


     
  • richardmitnick 10:59 am on May 7, 2015 Permalink | Reply
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    From Sanford via KDLT: “Unlocking Mysteries of Dark Matter & Neutrinos in South Dakota” 

    Sanford Underground Research facility

    Sanford Underground levels

    Sanford Underground Research facility

    3
    KDLT

    May 06, 2015
    Tom Hanson, KDLT News Anchor

    The former Homestake Gold Mine in Lead closed in 2002. It is now the Sanford Underground Research Facility Funded by the state of South Dakota, the U.S. Department of Energy and a donation from T. Denny Sanford the lab is drawing some of the sharpest minds in science to South Dakota.

    The search for dark matter and the study of neutrinos are at the heart of two of the underground labs biggest projects. The equipment used in this research is so sensitive it has to be shielded from cosmic rays on the earth’s surface.

    Located almost a mile underground the LUX is a dark matter detector.

    Lux Dark Matter 2
    LUX Dark matter
    LUX

    2
    The two men behind the project Simon Fiorucci (left) and Harry Nelson are hunting something so rare, no one has ever seen it, in fact no one really knows exactly what it is.

    “We are trying to detect a new form of matter which we are absolutely sure constitutes about 85 percent of the matter in the universe,” said Nelson. “And the fabulous thing is no one knows what it is. So there are a bunch of conjectures and so the gadget behind us is dedicated to the most popular conjecture of what this dark matter of the universe is.”

    The gadget is the Large Underground Xenon Detector or LUX, a phone booth sized container holding liquid xenon, cooled to -160 degrees F and surrounded by thousands of gallons of specially treated water. And according to Sanford Underground Lab officials the LUX has the reputation as the most sensitive detector ever built. Nelson has a nack for taking a very complicated process and simplifying it.

    “Our detector occasionally should see a little touch of the dark matter and it will make the atoms in our detector recoil and emit a little bit of light and also make a little bit of electric charge, that’s what we are trying to do here,” said Nelson.

    But according to Fiorucci so far that hasn’t happened.

    “We’ve seen nothing at all, which at first glance you might think well that’s not great, actually what that means is we’ve eliminated quite a number of possibilities, said Fiorucci.

    4

    Possibilities surround the other big project currently underway at the Sanford lab. The Majorana Demonstrator is looking at neutrinos.

    Majorano Demonstrator Experiment
    Majorano

    Particles so small there are billions of them passing through your body as you read this story. Professor John Wilkerson and his team are searching for a rare form of radioactive decay.

    “If we see this rare decay it would actually tell us that neutrinos can be their own anti particle and it might explain why we exist, why there’s so much matter and why there’s not anti-matter in the universe,” said Wilkerson.

    The vast majority of the observable universe from our planet seems to be made of matter and not antimatter. Why? Is one of the most interesting questions facing scientists.

    Building on the success of the LUX and Majorana Demonstrator, the next generations of projects are coming to the underground facility.
    The LZ project will continue the search for dark matter and will be 30 times larger than the LUX.

    LZ project
    LZ Project

    However the Deep Underground Neutrino Experiment or DUNE will be the biggest of all.

    FNAL DUNE
    DUNE

    The $1.5 billion project will try to find out how neutrinos change from point A to point B. It involves shooting neutrinos through the earth from Fermilab in Illinois to a huge detector at the Sanford Underground Lab.

    The man in charge of the facility, executive director Brookings native Mike Headley says they are excited to be a part of the project.

    “This will really be a big deal”, said Headley. “It’s an international collaboration that has close to 150 institutions worldwide and over 700 collaborators. The Long Base Neutrino Experiment (also called DUNE) is basically a $1.5 billion project. It is 1/3 funded international 2/3 funded in U.S. About 300 million of that $1.5 Billion will be facility construction here in South Dakota, so it’s going to be one of the biggest construction projects we’ve ever had in the state.”

    Construction on DUNE will begin next year. Scientists behind the project say neutrinos could hold clues about how the universe began and why matter greatly outnumbers antimatter, allowing us to exist.

    See the full article here.

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    About us.
    The Sanford Underground Research Facility in Lead, South Dakota, advances our understanding of the universe by providing laboratory space deep underground, where sensitive physics experiments can be shielded from cosmic radiation. Researchers at the Sanford Lab explore some of the most challenging questions facing 21st century physics, such as the origin of matter, the nature of dark matter and the properties of neutrinos. The facility also hosts experiments in other disciplines—including geology, biology and engineering.

    The Sanford Lab is located at the former Homestake gold mine, which was a physics landmark long before being converted into a dedicated science facility. Nuclear chemist Ray Davis earned a share of the Nobel Prize for Physics in 2002 for a solar neutrino experiment he installed 4,850 feet underground in the mine.

    Homestake closed in 2003, but the company donated the property to South Dakota in 2006 for use as an underground laboratory. That same year, philanthropist T. Denny Sanford donated $70 million to the project. The South Dakota Legislature also created the South Dakota Science and Technology Authority to operate the lab. The state Legislature has committed more than $40 million in state funds to the project, and South Dakota also obtained a $10 million Community Development Block Grant to help rehabilitate the facility.

    In 2007, after the National Science Foundation named Homestake as the preferred site for a proposed national Deep Underground Science and Engineering Laboratory (DUSEL), the South Dakota Science and Technology Authority (SDSTA) began reopening the former gold mine.

    In December 2010, the National Science Board decided not to fund further design of DUSEL. However, in 2011 the Department of Energy, through the Lawrence Berkeley National Laboratory, agreed to support ongoing science operations at Sanford Lab, while investigating how to use the underground research facility for other longer-term experiments. The SDSTA, which owns Sanford Lab, continues to operate the facility under that agreement with Berkeley Lab.

    The first two major physics experiments at the Sanford Lab are 4,850 feet underground in an area called the Davis Campus, named for the late Ray Davis. The Large Underground Xenon (LUX) experiment is housed in the same cavern excavated for Ray Davis’s experiment in the 1960s. In October 2013, after an initial run of 80 days, LUX was determined to be the most sensitive detector yet to search for dark matter—a mysterious, yet-to-be-detected substance thought to be the most prevalent matter in the universe. The Majorana Demonstrator experiment, also on the 4850 Level, is searching for a rare phenomenon called “neutrinoless double-beta decay” that could reveal whether subatomic particles called neutrinos can be their own antiparticle. Detection of neutrinoless double-beta decay could help determine why matter prevailed over antimatter. The Majorana Demonstrator experiment is adjacent to the original Davis cavern.

    Another major experiment, the Long Baseline Neutrino Experiment (LBNE) [being replaced by DUNE]—a collaboration with Fermi National Accelerator Laboratory (Fermilab) and Sanford Lab, is in the preliminary design stages. The project got a major boost last year when Congress approved and the president signed an Omnibus Appropriations bill that will fund LBNE operations through FY 2014. Called the “next frontier of particle physics,” LBNE [DUNE] will follow neutrinos as they travel 800 miles through the earth, from FermiLab in Batavia, Ill., to Sanford Lab.

    Fermilab LBNE
    LBNE

     
  • richardmitnick 10:35 am on May 6, 2015 Permalink | Reply
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    From Nature: “Mysterious galactic signal points LHC to dark matter” 

    Nature Mag
    Nature

    06 May 2015
    Davide Castelvecchi

    1
    γ-rays (shown in false colour) emitted from the Galactic Centre are giving the LHC a firm target in its hunt for dark matter.

    It is one of the most disputed observations in physics. But an explanation may be in sight for a mysterious excess of high-energy photons at the centre of the Milky Way. The latest analysis suggests that the signal could come from a dark-matter particle that has just the right mass to show up at the world’s largest particle accelerator.

    The Large Hadron Collider (LHC), housed at the CERN particle-physics laboratory near Geneva, Switzerland, is due to restart colliding protons this summer after a two-year hiatus (see ‘LHC 2.0: A new view of the Universe‘). Physicists there have told Nature that they now plan to make the search for such a particle a top target for the collider’s second run.

    CERN LHC Map
    CERN LHC Grand Tunnel
    CERN LHC particles
    LHC

    A positive detection would resolve the source of the galactic γ-rays. But it would also reveal the nature of dark matter, the invisible stuff thought to make up around 85% of the Universe’s matter, and would be long-sought evidence for supersymmetry, a grand way to extend the current standard model of particle physics.

    2
    Standard Model of Particle Physics. The diagram shows the elementary particles of the Standard Model (the Higgs boson, the three generations of quarks and leptons, and the gauge bosons), including their names, masses, spins, charges, chiralities, and interactions with the strong, weak and electromagnetic forces. It also depicts the crucial role of the Higgs boson in electroweak symmetry breaking, and shows how the properties of the various particles differ in the (high-energy) symmetric phase (top) and the (low-energy) broken-symmetry phase (bottom).

    “This could very well be the single most promising explanation for the Galactic Centre proposed to date,” says Dan Hooper of the Fermi National Accelerator Laboratory (Fermilab) in Batavia, Illinois, although he adds that “there are quite a few others that are not too far behind”.

    In 2009, Hooper and Lisa Goodenough, then a graduate student at New York University, were the first to spot the signal, in data from NASA’s Fermi Gamma-Ray Space Telescope.

    NASA Fermi Telescope
    Fermi Gamma-Ray Space Telescope

    They proposed that the bump was a signature of dark matter. Two colliding dark-matter particles would annihilate each other, just as ordinary matter does with antimatter. The annihilation would generate a succession of short-lived particles that would eventually produce γ-rays.

    But the proposed particle, which has been dubbed the hooperon or gooperon after its proponents, soon ran into problems with physicists’ favourite version of supersymmetry. Although the minimal supersymmetric standard model (MSSM) allows for dark-matter particles with the estimated mass of hooperons — about 25–30 gigaelectronvolts (1 GeV is roughly the mass of a proton) — multiple experiments had suggested that the particles must be heavier. To accommodate hooperons, MSSM would have to be modified to an extent that makes many physicists uncomfortable. “It would have required a completely new theory,” says Sascha Caron, a particle physicist at Radboud University Nijmegen in the Netherlands, who leads the team behind the latest calculations.

    Sceptics suggested that the γ-ray excess spotted in the Fermi data had more-mundane explanations, such as emissions from neutron stars or from the remnants of exploded stars.

    But in late 2014, it emerged that calculations for the range of dark-matter-particle masses that would be compatible with the Fermi bump were too conservative. Fresh estimates of the γ-ray ‘noise’ produced by known sources, provided by the Fermi science team and others, allow for much heavier particles. “The excess can be explained with a particle of up to 200 GeV,” says Simona Murgia, a physicist at the University of California, Irvine, and a leading scientist in the Fermi team.

    Big-Bang fit

    Armed with this insight, Caron and his collaborators recalculated the predictions of the MSSM theory and found another potential explanation for the excess — an existing dark-matter candidate called a neutralino. The neutralino was heavy enough not to be excluded by previous experiments, yet light enough to potentially be produced in the second run of the LHC.

    Caron’s model also produces a prediction for the amount of dark matter that should have been created in the Big Bang that is compatible with state-of-the-art observations of the cosmic microwave background — the relic radiation of the Big Bang — performed by the European Space Agency’s Planck probe (see Nature http://doi.org/38k; 2014). This cannot be a coincidence, he says. “I find this quite amazing.”

    Cosmic Microwave Background  Planck
    CMB per Planck

    Caron’s team is not the only one reanalysing the Fermi bump in light of the new estimates. Similar but less-detailed calculations done by Fermilab physicist Patrick Fox and his colleagues last November also revealed the neutralino as a potential cause of the Fermi γ-rays. And Katherine Freese, director of Nordita, the Nordic Institute for Theoretical Physics in Stockholm, says that she and her collaborators have calculated that the excess could be caused by a type of dark matter that features in a less-popular theory of supersymmetry.

    Resolution may be just around the corner. In addition to being produced at the LHC, the neutralino could also be within the shooting range of next-generation underground experiments that are trying to catch dark-matter particles that happen to fly through Earth, says physicist Albert De Roeck, who works on the CMS, one of the two LHC detectors that will hunt for dark matter. If such a particle is indeed the cause of the γ-rays, he says, “it seems that the dark-matter signals should be observed very soon now”.

    See the full article here.

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    Nature is a weekly international journal publishing the finest peer-reviewed research in all fields of science and technology on the basis of its originality, importance, interdisciplinary interest, timeliness, accessibility, elegance and surprising conclusions. Nature also provides rapid, authoritative, insightful and arresting news and interpretation of topical and coming trends affecting science, scientists and the wider public.

     
  • richardmitnick 12:43 pm on April 29, 2015 Permalink | Reply
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    From Keck: “The Dark Matter Conspiracy” 

    Keck Observatory

    Keck Observatory

    Keck Observatory

    April 29, 2015
    MEDIA CONTACT
    Steve Jefferson
    W. M. Keck Observatory
    sjefferson@keck.hawaii.edu
    808.881.3827

    1
    Example of mapping out and analyzing the speeds of stars in an elliptical galaxy. Blue colors show regions where the stars are hurtling toward the observer on Earth, and red colors show regions that are moving away, in an overall pattern of coherent rotation. The top panel shows the original data, as collected using the DEIMOS spectrograph at the W.M. Keck Observatory. The bottom panel shows a numerical model that matches the data remarkably well, from using the combined gravitational influence of luminous and dark matter. Credit: M. Cappellari and the SLUGGS team

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    The speeds of stars on circular orbits have been measured around both spiral and elliptical galaxies. Without dark matter, the speeds should decrease with distance from the galaxy, at different rates for the two galaxy types. Instead, the dark matter appears to conspire to keep the speeds steady. Credit: M. Cappellari and the Sloan Digital Sky Survey

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    Computer simulation of a galaxy, with the dark matter colorized to make it visible. The dark matter surrounds and permeates the galaxy, holding it together and allowing stars and planets to form. Credit: Springel et al., Virgo Consortium, Max-Planck-Institute for Astrophysics

    An international team of astronomers, led by Michele Cappellari from the University of Oxford, has used data gathered by the W. M. Keck Observatory in Hawaii to analyze the motions of stars in the outer parts of elliptical galaxies, in the first such survey to capture large numbers of these galaxies. The team discovered surprising gravitational similarities between spiral and elliptical galaxies, implying the influence of hidden forces. The study will be published in The Astrophysical Journal Letters.

    The scientists from the USA, Australia, and Europe used the powerful DEIMOS spectrograph installed on the world’s largest optical telescope at Keck Observatory to conduct a major survey of nearby galaxies called SLUGGS, which mapped out the speeds of their stars.

    Keck DEIMOS
    DEIMOS spectrograph

    The team then applied Newton’s law of gravity to translate these speed measurements into the amounts of matter distributed within the galaxies.

    “The DEIMOS spectrograph was crucial for this discovery since it can take in data from an entire giant galaxy all at once, while at the same time sampling the speeds of its stars at a hundred separate locations with exquisite accuracy,” said Aaron Romanowsky, of San Jose State University.

    One of the most important scientific discoveries of the 20th century was that the spectacular spiral galaxies, such as our own Milky Way, rotate much faster than expected, powered by an extra gravitational force of invisible “dark matter” as it is now called. Since this discovery 40 years ago, we have learned that this mysterious substance, which is probably an exotic elementary particle, makes up about 85 percent of the mass in the Universe, leaving only 15 percent to be the ordinary stuff encountered in our everyday lives. Dark matter is central to our understanding of how galaxies form and evolve – and is ultimately one of the reasons for the existence of life on Earth – yet we know almost nothing about it.

    “The surprising finding of our study was that elliptical galaxies maintain a remarkably constant circular speed out to large distances from their centers, in the same way that spiral galaxies are already known to do,” said Cappellari. “This means that in these very different types of galaxies, stars and dark matter conspire to redistribute themselves to produce this effect, with stars dominating in the inner regions of the galaxies, and a gradual shift in the outer regions to dark matter dominance.”

    However, the conspiracy does not come out naturally from models of dark matter, and some disturbing fine-tuning is required to explain the observations. For this reason, the conspiracy even led some authors to suggest that, rather than being due to dark matter, it may be due to Newton’s law of gravity becoming progressively less accurate at large distances. Remarkably, decades after it was proposed, this alternative theory (without dark matter) still cannot be conclusively ruled out.

    Spiral galaxies only constitute less than half of the stellar mass in the Universe, which is dominated by elliptical and lenticular galaxies, and which have puffier configurations of stars and lack the flat disks of gas that spirals have. In these galaxies, it has been very difficult technically to measure their masses and to find out how much dark matter they have, and how this is distributed – until now.

    Because the elliptical galaxies have different shapes and formation histories than spiral galaxies, the newly discovered conspiracy is even more profound and will lead experts in dark matter and galaxy formation to think carefully about what has happened in the “dark sector” of the universe.

    “This question is particularly timely in this period when physicists at CERN are about to restart the Large Hadron Collider to try to directly detect the same elusive dark matter particle, which makes galaxies rotate fast, if it really exists!,” said Professor Jean Brodie, principal investigator of the SLUGGS survey.

    The W. M. Keck Observatory operates the largest, most scientifically productive telescopes on Earth. The two, 10-meter optical/infrared telescopes near the summit of Mauna Kea on the Island of Hawaii feature a suite of advanced instruments including imagers, multi-object spectrographs, high-resolution spectrographs, integral-field spectrographs and world-leading laser guide star adaptive optics systems.

    DEIMOS (the DEep Imaging and Multi-Object Spectrograph) boasts the largest field of view (16.7 arcmin by 5 arcmin) of any of the Keck instruments, and the largest number of pixels (64 Mpix). It is used primarily in its multi-object mode, obtaining simultaneous spectra of up to 130 galaxies or stars. Astronomers study fields of both nearby and distant galaxies with DEIMOS, efficiently probing the most distant corners of the universe with high sensitivity.

    See the full article here.

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    Mission
    To advance the frontiers of astronomy and share our discoveries with the world.

    The W. M. Keck Observatory operates the largest, most scientifically productive telescopes on Earth. The two, 10-meter optical/infrared telescopes on the summit of Mauna Kea on the Island of Hawaii feature a suite of advanced instruments including imagers, multi-object spectrographs, high-resolution spectrographs, integral-field spectrometer and world-leading laser guide star adaptive optics systems. Keck Observatory is a private 501(c) 3 non-profit organization and a scientific partnership of the California Institute of Technology, the University of California and NASA.

    Today Keck Observatory is supported by both public funding sources and private philanthropy. As a 501(c)3, the organization is managed by the California Association for Research in Astronomy (CARA), whose Board of Directors includes representatives from the California Institute of Technology and the University of California, with liaisons to the board from NASA and the Keck Foundation.
    Keck UCal

    Keck NASA

    Keck Caltech

     
  • richardmitnick 9:24 am on April 20, 2015 Permalink | Reply
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    From Don Lincoln at FNAL: “Complex Dark Matter” 

    FNAL Home

    Fermilab is an enduring source of strength for the US contribution to scientific research world wide.

    FNAL Don Lincoln
    Don Lincoln

    After a century of study, scientists have come to the realization that the ordinary matter made of atoms is a minority in the universe. In order to explain observations, it appears that there exists a new and undiscovered kind of matter, called dark matter, that is five times more prevalent than ordinary matter. The evidence for this new matter’s existence is very strong, but scientists know only a little about its nature. In today’s video, Fermilab’s Dr. Don Lincoln talks about an exciting and unconventional idea, specifically that dark matter might have a very complex set of structures and interactions. While this idea is entirely speculative, it is an interesting hypothesis and one that scientists are investigating.

    See the full article here.

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    Fermilab Campus

    Fermi National Accelerator Laboratory (Fermilab), located just outside Batavia, Illinois, near Chicago, is a US Department of Energy national laboratory specializing in high-energy particle physics. Fermilab is America’s premier laboratory for particle physics and accelerator research, funded by the U.S. Department of Energy. Thousands of scientists from universities and laboratories around the world
    collaborate at Fermilab on experiments at the frontiers of discovery.

     
  • richardmitnick 8:42 am on April 14, 2015 Permalink | Reply
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    From FNAL: “Mapping the cosmos: Dark Energy Survey creates detailed guide to spotting dark matter” 

    FNAL Home

    Fermilab is an enduring source of strength for the US contribution to scientific research world wide.

    Media contacts:

    Andre Salles, Fermilab Office of Communication, 630-840-3351, media@fnal.gov

    Science contacts:

    Josh Frieman, director of the Dark Energy Survey, 847-274-0429, frieman@fnal.gov
    Chihway Chang, ETH Zurich, +41-798101425, chihway.chang@phys.ethz.ch
    Bhuvnesh Jain, University of Pennsylvania, 267-973-7063, bjain@physics.upenn.edu
    Gary Bernstein, University of Pennsylvania, 215-573-6252, garyb@physics.upenn.edu

    Analysis will help scientists understand the role that dark matter plays in galaxy formation

    1
    This is the first Dark Energy Survey map to trace the detailed distribution of dark matter across a large area of sky. The color scale represents projected mass density: red and yellow represent regions with more dense matter. The dark matter maps reflect the current picture of mass distribution in the universe where large filaments of matter align with galaxies and clusters of galaxies. Clusters of galaxies are represented by gray dots on the map – bigger dots represent larger clusters. This map covers three percent of the area of sky that DES will eventually document over its five-year mission. Image: Dark Energy Survey

    Dark Energy Survey
    Dark Energy Camera
    CTIO Victor M Blanco 4m Telescope
    CTIO Victor M Blanco 4m Telescope interior
    Dark Energy Survey; Camera, built at FNAL; and CTIO Victor M Blanco 4 meter telescope which houses the DECam Camera

    Scientists on the Dark Energy Survey have released the first in a series of dark matter maps of the cosmos. These maps, created with one of the world’s most powerful digital cameras, are the largest contiguous maps created at this level of detail and will improve our understanding of dark matter’s role in the formation of galaxies. Analysis of the clumpiness of the dark matter in the maps will also allow scientists to probe the nature of the mysterious dark energy, believed to be causing the expansion of the universe to speed up.

    The new maps were released today at the April meeting of the American Physical Society in Baltimore, Maryland. They were created using data captured by the Dark Energy Camera, a 570-megapixel imaging device that is the primary instrument for the Dark Energy Survey (DES).

    Dark matter, the mysterious substance that makes up roughly a quarter of the universe, is invisible to even the most sensitive astronomical instruments because it does not emit or block light. But its effects can be seen by studying a phenomenon called gravitational lensing – the distortion that occurs when the gravitational pull of dark matter bends light around distant galaxies. Understanding the role of dark matter is part of the research program to quantify the role of dark energy, which is the ultimate goal of the survey.

    This analysis was led by Vinu Vikram of Argonne National Laboratory (then at the University of Pennsylvania) and Chihway Chang of ETH Zurich. Vikram, Chang and their collaborators at Penn, ETH Zurich, the University of Portsmouth, the University of Manchester and other DES institutions worked for more than a year to carefully validate the lensing maps.

    “We measured the barely perceptible distortions in the shapes of about 2 million galaxies to construct these new maps,” Vikram said. “They are a testament not only to the sensitivity of the Dark Energy Camera, but also to the rigorous work by our lensing team to understand its sensitivity so well that we can get exacting results from it.”

    The camera was constructed and tested at the U.S. Department of Energy’s Fermi National Accelerator Laboratory and is now mounted on the 4-meter Victor M. Blanco telescope at the National Optical Astronomy Observatory’s Cerro Tololo Inter-American Observatory in Chile. The data were processed at the National Center for Supercomputing Applications at the University of Illinois in Urbana-Champaign.

    The dark matter map released today makes use of early DES observations and covers only about three percent of the area of sky DES will document over its five-year mission. The survey has just completed its second year. As scientists expand their search, they will be able to better test current cosmological theories by comparing the amounts of dark and visible matter.

    Those theories suggest that, since there is much more dark matter in the universe than visible matter, galaxies will form where large concentrations of dark matter (and hence stronger gravity) are present. So far, the DES analysis backs this up: The maps show large filaments of matter along which visible galaxies and galaxy clusters lie and cosmic voids where very few galaxies reside. Follow-up studies of some of the enormous filaments and voids, and the enormous volume of data, collected throughout the survey will reveal more about this interplay of mass and light.

    “Our analysis so far is in line with what the current picture of the universe predicts,” Chang said. “Zooming into the maps, we have measured how dark matter envelops galaxies of different types and how together they evolve over cosmic time. We are eager to use the new data coming in to make much stricter tests of theoretical models.”

    View the Dark Energy Survey analysis.

    The Dark Energy Survey is a collaboration of more than 300 scientists from 25 institutions in six countries. Its primary instrument, the Dark Energy Camera, is mounted on the 4-meter Blanco telescope at the National Optical Astronomy Observatory’s Cerro Tololo Inter-American Observatory in Chile, and its data is processed at the National Center for Supercomputing Applications at the University of Illinois at Urbana-Champaign.

    Funding for the DES Projects has been provided by the U.S. Department of Energy Office of Science, the U.S. National Science Foundation, the Ministry of Science and Education of Spain, the Science and Technology Facilities Council of the United Kingdom, the Higher Education Funding Council for England, ETH Zurich for Switzerland, the National Center for Supercomputing Applications at the University of Illinois at Urbana-Champaign, the Kavli Institute of Cosmological Physics at the University of Chicago, Financiadora de Estudos e Projetos, Fundação Carlos Chagas Filho de Amparo à Pesquisa do Estado do Rio de Janeiro, Conselho Nacional de Desenvolvimento Científico e Tecnológico and the Ministério da Ciência e Tecnologia, the Deutsche Forschungsgemeinschaft and the collaborating institutions in the Dark Energy Survey. The DES participants from Spanish institutions are partially supported by MINECO under grants AYA2012-39559, ESP2013-48274, FPA2013-47986 and Centro de Excelencia Severo Ochoa SEV-2012-0234, some of which include ERDF funds from the European Union.

    Fermilab is America’s premier national laboratory for particle physics and accelerator research. A U.S. Department of Energy Office of Science laboratory, Fermilab is located near Chicago, Illinois, and operated under contract by the Fermi Research Alliance, LLC. Visit Fermilab’s website at http://www.fnal.gov and follow us on Twitter at @Fermilab.

    The DOE Office of Science is the single largest supporter of basic research in the physical sciences in the United States and is working to address some of the most pressing challenges of our time. For more information, please visit science.energy.gov.

    See the full article here.

    Please help promote STEM in your local schools.

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    Fermilab Campus

    Fermi National Accelerator Laboratory (Fermilab), located just outside Batavia, Illinois, near Chicago, is a US Department of Energy national laboratory specializing in high-energy particle physics. Fermilab is America’s premier laboratory for particle physics and accelerator research, funded by the U.S. Department of Energy. Thousands of scientists from universities and laboratories around the world
    collaborate at Fermilab on experiments at the frontiers of discovery.

     
  • richardmitnick 12:48 pm on April 13, 2015 Permalink | Reply
    Tags: , , Dark Energy/Dark Matter,   

    From New Scientist: “Looking into the voids could help explain dark energy” 

    NewScientist

    New Scientist

    10 April 2015
    Anil Ananthaswamy

    1
    A complex web (Image: Volker Springle/Max Planck Institute for Astrophysics/SP)

    HOLES in the universe could help explain why it’s ripping apart. The number and size of cosmic voids could shed light on the mysterious dark energy that is causing the universe to grow at an ever-increasing pace.

    In the late 1990s, astronomers realised that the expansion of the universe was accelerating and attributed this to the inherent “dark energy” of space-time.

    But we understand little about dark energy. Each unit of space-time contains some, but if this energy density changes with time, it implies different fates for our universe. If it is constant, as current observations suggest, then the universe will expand forever. But if it changes, we could be heading for a more dramatic end, like a big rip or a big crunch.

    One way to understand whether dark energy changes with time is to observe its effect on the large-scale structure of the universe. Just instants after the big bang, quantum fluctuations in the fabric of space-time led to regions that had more matter than their neighbours. As the universe expanded, the denser regions evolved to form clusters of galaxies. The less dense regions became voids – regions of space-time almost empty of matter, which can stretch from 30 million to 150 million light years across.

    While most efforts at deciphering dark energy involve studying its effect on clusters of galaxies, Alice Pisani and colleagues at the Paris Institute of Astrophysics decided to see if dark energy influenced the number of voids in the universe. “Voids are just an unavoidable part of the distribution of matter in the universe,” says team member Benjamin Wandelt.

    It turns out that there was a time in the evolution of the universe when the effects of dark energy kicked in and stopped the formation of new large-scale structures, whether clusters or voids. The properties of dark energy influenced when this happened and therefore the distribution of these structures.

    Pisani and colleagues considered three scenarios, all of which can explain the observed rate of expansion today. One was that dark energy is a cosmological constant [Λ]; in the other scenarios, dark energy changed with time. The second caused the expansion to accelerate later but faster than the cosmological constant would have, and in the third, it was earlier but slower.

    “Depending exactly on when the universe started accelerating, you have more or less voids of various sizes,” says Wandelt. The team’s analysis shows that with later but faster acceleration, there should be more big voids but fewer smaller ones compared with the cosmological constant. The opposite would be the case for acceleration that began earlier but was slower (arxiv.org/abs/1503.07690).

    Observations are not yet good enough to differentiate between the three scenarios but the European Space Agency’s Euclid mission, due for launch in 2020, will study more voids than ever before. The Paris team says its analysis could be applied to the Euclid data to elucidate dark energy, alongside studies investigating clusters.

    ESA Euclid spacecraft
    ESA/Euclid

    See the full article here.

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  • richardmitnick 3:25 pm on April 3, 2015 Permalink | Reply
    Tags: , Dark Energy/Dark Matter,   

    From FNAL: “Frontier Science Result – PICO Seeing dark matter 

    FNAL Home

    Fermilab is an enduring source of strength for the US contribution to scientific research world wide.

    April 3, 2015
    Alan Robinson, University of Chicago

    1
    A calibration event from PICO-2L shows boiling from multiple recoiling atomic nuclei. PICO-2L is designed to see a recoiling nucleus a from dark matter interaction.

    We are not yet seeing dark matter, but we could.

    Dark matter is all around us. There is six times more dark matter in our universe than there is the ordinary matter that we experience every day. Like neutrinos, dark matter can pass right through us and the Earth without being noticed. Moreover, dark matter does not interact with light, so we cannot see it, except perhaps in a bubble chamber.

    2
    Fermilab’s disused 15-foot bubble chamber

    Temp 0
    A bubble chamber

    Bubble chambers, including Fermilab’s 15-foot bubble chamber, were among the largest and most important particle detectors of the 1960s and 1970s investigating the physics of the weak force. In operation, bubble chambers are filled with liquid held above its boiling point temperature at the bubble chamber’s expansion pressure. The liquid boils if a nucleation site, such as a dust grain or a surface scratch, is available. In their absence, ionizing radiation (that is, particle tracks) can create bubbles. The exploding line of bubbles formed along a track lets physicists “see” the particle and photograph it.

    The PICO collaboration, of which Fermilab is a member (formed from the merger of PICASSO and COUPP), has revisited bubble chamber technology in order to look for dark matter particles. While dark matter particles pass through the Earth, they may very occasionally bounce off an atomic nucleus. PICO bubble chambers can see these nuclear recoils. They do not see most other types of ionizing radiation that can emulate dark matter in other detector technologies. PICO can also see bubbles from alpha radiation, but these are distinguishable as they sound different from those made by dark matter. As a bubble rapidly grows, PICO uses ultrasonic acoustic sensors to measure the sound of this small explosion and to reject the louder bubbles created by alpha radiation.

    The PICO-2L bubble chamber operated in 2013 and 2014 at SNOLAB, 6,800 feet underground in a Canadian nickel mine. Using 2 liters of perfluoropropane, C3F8, PICO-2L has set the world’s strongest proton spin-dependent dark matter search limits. Fluorine provides the most sensitive target nucleus to detect a spin-dependent dark matter interaction, which means future large bubble chambers may see, and hear, dark matter interactions that other detectors can not.

    3
    PICO-2L bubble chamber

    See the full article here.

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    Fermilab Campus

    Fermi National Accelerator Laboratory (Fermilab), located just outside Batavia, Illinois, near Chicago, is a US Department of Energy national laboratory specializing in high-energy particle physics. Fermilab is America’s premier laboratory for particle physics and accelerator research, funded by the U.S. Department of Energy. Thousands of scientists from universities and laboratories around the world
    collaborate at Fermilab on experiments at the frontiers of discovery.

     
  • richardmitnick 10:42 am on March 25, 2015 Permalink | Reply
    Tags: , , Dark Energy/Dark Matter,   

    From FNAL: “From the Center for Particle Astrophysics – Building a dark matter radio” 

    FNAL Home

    Fermilab is an enduring source of strength for the US contribution to scientific research world wide.

    1
    Craig Hogan, head of the Center for Particle Astrophysics, wrote this column.

    You may have heard lately that the famous cosmic dark matter — the mysterious new kind of stuff that makes up most of the gravitational mass of the universe — may not, in fact, be completely dark, but may actually emit small amounts of light. That would be very exciting, because we might detect the light and use it to help figure out what the stuff is made of.

    For example, the Fermi Gamma-Ray Space Telescope detects light, in the form of photons from the center of our galaxy, that may be caused by massive dark matter particles annihilating each other.

    NASA Fermi Telescope
    NASA/Fermi

    Such high-energy photons can be created if the individual dark matter particles themselves are massive— much more massive than any known stable particle.

    But it’s also possible that the dark matter particles have extraordinarily low mass — even smaller than the tiny masses associated with neutrinos. In that case, the light emitted by dark matter, if any, would not show up as high-energy gamma rays; instead, it would show up as radio waves. Indeed, even the dark matter itself acts more like a coherent oscillating wave field than a collection of individual particles. In this situation, the best way to search for them may not be a traditional particle detector but a receiver more like a radio.

    A leading candidate for this kind of dark matter is called an axion. The existence of such a field was predicted long ago, not from a need for dark matter, but as a way to explain why strong interactions (the quantum chromodynamics of the Standard Model that control the structure of atomic nuclei) do not appear to distinguish the past from the future as the other interactions do.

    2
    Standard Model of Particle Physics. The diagram shows the elementary particles of the Standard Model (the Higgs boson, the three generations of quarks and leptons, and the gauge bosons), including their names, masses, spins, charges, chiralities, and interactions with the strong, weak and electromagnetic forces. It also depicts the crucial role of the Higgs boson in electroweak symmetry breaking, and shows how the properties of the various particles differ in the (high-energy) symmetric phase (top) and the (low-energy) broken-symmetry phase (bottom).

    In standard cosmology, if such a particle has a low mass, roughly in the microwave range of radio frequencies, it could be produced in sufficient abundance to be some, or even all, of the cosmic dark matter.

    If so, we might find them in the laboratory. It turns out that if cosmic axions from our galaxy pass through a strong magnet, they give off a small amount of radio light at exactly the frequency corresponding to their tiny mass. To detect them, we want to build a radio tuned to that mass. The radio in this case uses a highly resonant cavity, similar to those that Fermilab uses all the time to accelerate particles. We don’t know the mass of the axion exactly, so to search for the axion, we have to tune the radio — the cavity — until we get a signal.

    The Axion Dark Matter Experiment has started a search like this at the University of Washington.

    ADMX Axion Dark Matter Experiment
    AXION DME
    Axion Dark Matter Experiment, U Washington

    (Because the experiment is not sensitive to cosmic rays, the actual apparatus does not have to be deep underground, but is on campus.) The tuning starts at low frequencies, searching for axions of relatively low mass, where it can use relatively large cavities. But there is a long way to go: Theory provides only a rough guess about the mass of the axion, and nobody yet knows exactly how to build smaller cavities that can efficiently search for higher-mass axions.

    Fermilab scientists and engineers are planning to make unique contributions to state-of-the-art higher-frequency cavity designs for the higher-mass search, drawing on their years of experience with radio-frequency cavities in accelerators. This unique fusion of accelerator science and dark matter science is an exciting example of the synergy that happens at Fermilab.

    See the full article here.

    Please help promote STEM in your local schools.

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    Fermilab Campus

    Fermi National Accelerator Laboratory (Fermilab), located just outside Batavia, Illinois, near Chicago, is a US Department of Energy national laboratory specializing in high-energy particle physics. Fermilab is America’s premier laboratory for particle physics and accelerator research, funded by the U.S. Department of Energy. Thousands of scientists from universities and laboratories around the world
    collaborate at Fermilab on experiments at the frontiers of discovery.

     
  • richardmitnick 1:18 pm on March 21, 2015 Permalink | Reply
    Tags: , , Dark Energy/Dark Matter, U Notre Dame   

    From Notre Dame: “New paper explains methods that may lead to new insights about dark matter” 

    Notre Dame bloc

    Notre Dame University

    2
    This is Henize 2-10, a blob-shaped dwarf galaxy 30 million light-years away. The tiny galaxy has a colossal black hole at its center and could be a transition between young, small galaxies and massive spirals like our Milky Way, suggesting that galaxies form around central black holes, not the other way around. Astronomers suggest think that Henize 2-10 could be a nearby example of some of the first galaxies ever formed in the universe. Image is from NASA/Chandra, NASA/ESA Hubble NRAO/VLA January 10, 2011

    NASA Chandra Telescope
    NASA/Chandra

    NASA Hubble Telescope
    NASA/ESA Hubble

    NRAO VLA
    NRAO/VLA

    1
    Illustration of dark matter falling into a neutron star, forming a black hole and radiating out (Courtesy of NASA)

    A new paper, co-authored by University of Notre Dame astrophysicist Joseph Bramante, discusses how detecting imploding pulsars may lead to insights about the properties of dark matter. The paper, Detecting Dark Matter with Imploding Pulsars in the Galactic Center, was recently published in Physical Review Letters, the flagship journal for the American Physical Society.

    Pulsars, or pulsating stars, are rotating neutron stars that emit pulses of light visible to astronomers on Earth. Pulsars are created from the collapsing cores of supermassive stars that have exploded into supernovae. These supermassive stars, 10 to 40 times the mass of the sun, have been found at the center of the galaxy, leading astronomers to predict a certain number of pulsars should also reside there, but that predicted number of pulsars has not yet been observed.

    “In 2013, the first pulsar at the galactic center was detected, and this observation has deepened the mystery of these stellar objects,” explained Bramante, a postdoctoral associate in the lab of Christopher Kolda. “Prior to this detection, it was thought that pulsars at the galactic center might simply be shielded from observation by dense material in the center of the galaxy.”

    In the paper, Bramante and his colleague at the University of Chicago, Tim Linden, discuss how dark matter could explain the absence of pulsars in the galactic center. Dark matter, which makes up approximately 25 percent of the matter in the universe, is a very dense type of matter that does not emit a significant amount of light. A particular kind of dark matter could destroy pulsars at the galactic center by falling into the pulsars and forming black holes that swallow them.

    “Observations of pulsars imploding into black holes could provide important clues to the properties of dark matter, specifically indicating it is asymmetric, just like visible matter,” said Bramante.

    The paper also explains how the researchers showed that the presently unknown mass and quantum couplings of dark matter could be found by determining the age at which a pulsar is swallowed by a dark matter black hole. One predictor of this pulsar-collapsing dark matter is a maximum age for pulsars, which gets higher the further away from the galactic center the pulsars are because there is less dark matter away from the center.

    The next steps in this work for Bramante and his collaborators includes building and testing a model of dark matter to ensure the model meets all other cosmological and astrophysical dark matter observations.

    See the full article here.

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    Notre Dame Campus

    The University of Notre Dame du Lac (or simply Notre Dame /ˌnoʊtərˈdeɪm/ NOH-tər-DAYM) is a Catholic research university located near South Bend, Indiana, in the United States. In French, Notre Dame du Lac means “Our Lady of the Lake” and refers to the university’s patron saint, the Virgin Mary.

    The school was founded by Father Edward Sorin, CSC, who was also its first president. Today, many Holy Cross priests continue to work for the university, including as its president. It was established as an all-male institution on November 26, 1842, on land donated by the Bishop of Vincennes. The university first enrolled women undergraduates in 1972. As of 2013 about 48 percent of the student body was female.[6] Notre Dame’s Catholic character is reflected in its explicit commitment to the Catholic faith, numerous ministries funded by the school, and the architecture around campus. The university is consistently ranked one of the top universities in the United States and as a major global university.

    The university today is organized into five colleges and one professional school, and its graduate program has 15 master’s and 26 doctoral degree programs.[7][8] Over 80% of the university’s 8,000 undergraduates live on campus in one of 29 single-sex residence halls, each of which fields teams for more than a dozen intramural sports, and the university counts approximately 120,000 alumni.[9]

    The university is globally recognized for its Notre Dame School of Architecture, a faculty that teaches (pre-modernist) traditional and classical architecture and urban planning (e.g. following the principles of New Urbanism and New Classical Architecture).[10] It also awards the renowned annual Driehaus Architecture Prize.

     
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