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  • richardmitnick 2:40 pm on September 15, 2014 Permalink | Reply
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    From The Dark Energy Survey: “Distant Wanderer” 

    Dark Energy Icon
    The Dark Energy Survey

    Dark Energy Detectives

    No Date
    Det. D. Gerdes

    After a great journey, a long-hidden member of our solar system has returned. Not since the 9th century, when Charlemagne ruled as Emperor of the Holy Roman Empire and Chinese culture flourished under the Tang Dynasty, has this small icy world re-entered the realm of the outer planets.

    wandersr

    This distant wanderer is among first of its kind discovered with data from the Dark Energy Survey (DES). Now officially known as 2013 TV158, it first came into view on October 14, 2013, and has been observed several dozen more times over the following 10 months as it slowly traces the cosmic path laid out for it by Newton’s law of gravitation. We see this small object move in the animation to the left, comprised of a pair of images taken two hours apart in August, 2014.

    It takes almost 1200 years for 2013 TV158 to orbit the sun, and it is probably a few hundred kilometers across – about the length of the Grand Canyon.

    In eight more years, it will make its closest approach to the sun – still a billion kilometers beyond Neptune. At this distance, the sun would shine with less than a tenth of a percent of its brightness here on earth, and would appear no larger than a dime seen from a hundred feet away.

    That’s what high noon looks like on 2013 TV158.

    Then it will begin its six-century outbound journey, slowly fading from the view of even the most powerful telescopes, eventually reaching a distance of nearly 30 billion kilometers before pirouetting toward home again sometime in the 27th century.

    This object is just one of countless tiny worlds that inhabit the frozen outer region of the solar system called the Kuiper Belt, an expanse 20 times as wide and many times more massive than the asteroid belt between Mars and Jupiter. The dwarf planet Pluto also calls the Kuiper Belt its home. The orbits of Jupiter, Pluto and 2013 TV158 around the sun can be seen in the image to the lower right.

    kb
    Known objects in the Kuiper belt, derived from data from the Minor Planet Center. Objects in the main belt are colored green, whereas scattered objects are colored orange. The four outer planets are blue. Neptune’s few known trojans are yellow, whereas Jupiter’s are pink. The scattered objects between Jupiter’s orbit and the Kuiper belt are known as centaurs. The scale is in astronomical units. The pronounced gap at the bottom is due to difficulties in detection against the background of the plane of the Milky Way.

    Scientists believe that these Kuiper Belt Objects, or KBOs, are relics from the formation of the solar system, cosmic leftovers that never merged into one of the larger planets. By studying them, we can gain a better understanding of the processes that gave birth to the solar system 4.5 billion years ago.

    image
    Because they are so distant and faint, KBOs are extremely difficult to detect. The first KBO, Pluto, was discovered in 1930. Sixty-two years would pass before astronomers found the next one. Astronomers have identified well over half a million objects in the main asteroid belt between Mars and Jupiter. To date, we know of only about 1500 KBOs.

    DES is designed to peer far beyond our galaxy, to find millions of galaxies and thousands of supernovae, but it can also do much more. DES records images of ten specific patches of the sky each week between August and February. These images are a perfect hunting ground for KBOs, which move slowly enough that they can stay in the same field of view for weeks or even months. This allows us to look for objects that appear in different places on different nights, and eventually track the orbit over many nights of observations.

    So far we’ve searched less than one percent of the DES survey area for new KBOs. Who knows what other distant new worlds will wander into view?

    Det. D. Gerdes

    Dark Energy Camera
    CTIO Victor M Blanco 4m Telescope
    CTIO Victor M Blanco 4m Telescope interior
    The Dark Energy camera, DECam, built at Fermilab, and its home, the Victor M.Blanco 4m Telescope in Chile

    See the full article here.

    The Dark Energy Survey (DES) is designed to probe the origin of the accelerating universe and help uncover the nature of dark energy by measuring the 14-billion-year history of cosmic expansion with high precision. More than 120 scientists from 23 institutions in the United States, Spain, the United Kingdom, Brazil, and Germany are working on the project. This collaboration [has built] an extremely sensitive 570-Megapixel digital camera, DECam, and will mount it on the Blanco 4-meter telescope at Cerro Tololo Inter-American Observatory high in the Chilean Andes. Starting in Sept. 2012 and continuing for five years, DES will survey a large swath of the southern sky out to vast distances in order to provide new clues to this most fundamental of questions.

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  • richardmitnick 1:45 pm on September 12, 2014 Permalink | Reply
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    From FNAL- “Frontier Science Result: DES Dark Energy Survey discovers new trans-Neptunian objects” 


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

    Friday, Sept. 12, 2014
    David Gerdes, University of Michigan

    three
    Planet hunters, from left: Zhilu Zhang (Carleton College), David Gerdes (University of Michigan) and Ross Jennings (Carleton College)

    Ever wish you could spend your summer vacation exploring someplace cool? Undergraduate students Ross Jennings and Zhilu Zhang, both of Carleton College, got to explore one of the coolest places in the solar system when they accepted research fellowships at the University of Michigan to work with Professor David Gerdes on a search for trans-Neptunian minor planets with the Dark Energy Survey. This faraway region of the solar system, more than five billion kilometers from the sun, is populated by thousands of small, icy worlds that take centuries to complete one orbit. These trans-Neptunian objects (TNOs) are believed to be leftovers from the primordial cloud that gave birth to the solar system.

    two
    These side-by-side images show the new minor planet 2013 QO95. The circled object in the left picture is roughly 200 kilometers in size and lies just beyond Pluto. The bright star in the image is too faint to be seen with the unaided eye. Images: Dark Energy Survey

    Dark Energy Camera
    Dark Energy Camera on the Blanco 4-meter telescope at Cerro Tololo Inter-American Observatory high in the Chilean Andes.

    CTIO Victor M Blanco 4m Telescope
    CTIO Victor M Blanco 4m Telescope interior
    CTIO Victor M Blanco 4m Telescope

    To look for TNOs in Dark Energy Survey data, Gerdes and his students examined the 10 fields that DES visits roughly every five days to search for type Ia supernovae. This search uses difference imaging software to detect transient objects such as a supernova that brightens rapidly and then fades over the next few months. But it’s also the perfect tool to find TNOs, which move from night to night against the background of fixed stars, yet slowly enough that they can stay in the same field of observation for weeks.

    Gerdes, Jennings and Zhang started with a list of nearly 100,000 observations of individual transients, then linked different combinations with trial orbits to see which ones were consistent with a TNO. As more and more points were added to each candidate orbit, the team refined their calculations and made improved predictions for additional observations. By the end of the summer, the team had discovered five new TNOs.

    The properties of the new objects reflect the rich dynamical structure of the trans-Neptunian region: One orbits the sun once for every two orbits of Neptune, and another makes two orbits for every five of Neptune. These orbital resonances protect the objects from disruptive close encounters with the giant planet. A third object has a highly elongated, 1,200-year orbit that is among the 50 longest orbital periods known. (Read more about the fourth and fifth objects.)

    In the course of this summer project, the students learned a variety of skills, from Python programming to the mechanics of submitting results for publication.

    But the most important thing, said Zhang, was this: “You need to really have a lot of enthusiasm for the research you are involved in, because there is a lot of repetition and tedious work involved in research, and it is not about discovering new things every day. However, the joy you get after you finally find something is so special that I haven’t felt anything like that before in my entire life.”

    Now that’s cool.

    See the full article here.

    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.

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  • richardmitnick 3:41 pm on August 18, 2014 Permalink | Reply
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    From Symmetry: “Dark Energy Survey kicks off second season” 

    Symmetry

    August 18, 2014
    No Writer Credit

    On August 15, with its successful first season behind it, the Dark Energy Survey collaboration began its second year of mapping the southern sky in unprecedented detail. Using the Dark Energy Camera, a 570-megapixel imaging device built by the collaboration and mounted on the Victor M. Blanco Telescope in Chile, the survey’s five-year mission is to unravel the fundamental mystery of dark energy and its impact on our universe.

    CTIO Victor M Blanco 4m Telescope
    Victor M Blanco 4m Telescope

    Dark Energy Camera
    Dark Energy Camera

    Along the way, the survey will take some of the most breathtaking pictures of the cosmos ever captured. The survey team has announced two ways the public can see the images from the first year.

    Today, the Dark Energy Survey relaunched its photo blog, Dark Energy Detectives. Once every two weeks during the survey’s second season, a new image or video will be posted to http://www.darkenergydetectives.org with an explanation provided by a scientist. During its first year, Dark Energy Detectives drew thousands of readers and followers, including more than 46,000 followers on its Tumblr site.

    Starting on September 1, the one-year anniversary of the start of the survey, the data collected by DES in its first season will become freely available to researchers worldwide. The data will be hosted by the National Optical Astronomy Observatory. The Blanco Telescope is hosted at the National Science Foundation’s Cerro Tololo Inter-American Observatory, the southern branch of NOAO.

    In addition, the hundreds of thousands of individual images of the sky taken during the first season are being analyzed by thousands of computers at the National Center for Supercomputing Applications at the University of Illinois at Urbana-Champaign, Fermi National Accelerator Laboratory and Lawrence Berkeley National Laboratory. The processed data will also be released in coming months.

    Scientists on the survey will use these images to unravel the secrets of dark energy, the mysterious substance that makes up 70 percent of the mass and energy of the universe. Scientists have theorized that dark energy works in opposition to gravity and is responsible for the accelerating expansion of the universe.

    “The first season was a resounding success, and we’ve already captured reams of data that will improve our understanding of the cosmos,” says DES Director Josh Frieman of Fermilab and the University of Chicago. “We’re very excited to get the second season under way and continue to probe the mystery of dark energy.”

    While results on the survey’s probe of dark energy are still more than a year away, a number of scientific results have already been published based on data collected with the Dark Energy Camera.

    The first scientific paper based on Dark Energy Survey data was published in May by a team led by Ohio State University’s Peter Melchior. Using data that the survey team acquired while putting the Dark Energy Camera through its paces, they used a technique called gravitational lensing to determine the masses of clusters of galaxies.

    In June, Dark Energy Survey researchers from the University of Portsmouth and their colleagues discovered a rare superluminous supernova in a galaxy 7.8 billion light years away. A group of students from the University of Michigan discovered five new objects in the Kuiper Belt, a region in the outer reaches of our solar system, including one that takes over a thousand years to orbit the Sun.

    kuiper
    Kuiper Belt

    In February, Dark Energy Survey scientists used the camera to track a potentially hazardous asteroid that approached Earth. The data was used to show that the newly discovered Apollo-class asteroid 2014 BE63 would pose no risk.

    Several more results are expected in the coming months, says Gary Bernstein of the University of Pennsylvania, project scientist for the Dark Energy Survey.

    The Dark Energy Camera was built and tested at Fermilab. The camera can see light from more than 100,000 galaxies up to 8 billion light-years away in each crystal-clear digital snapshot.

    “The Dark Energy Camera has proven to be a tremendous tool, not only for the Dark Energy Survey, but also for other important observations conducted year-round,” says Tom Diehl of Fermilab, operations scientist for the Dark Energy Survey. “The data collected during the survey’s first year—and its next four—will greatly improve our understanding of the way our universe works.”

    See the full article here.

    Symmetry is a joint Fermilab/SLAC publication.


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  • richardmitnick 9:23 am on July 10, 2014 Permalink | Reply
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    From Fermilab- “The sky is not the limit: DES gets time on Gemini telescope” 


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

    Thursday, July 10, 2014
    Hanae Armitage

    In an ambitious five-year mission, the Dark Energy Survey team has devoted itself to mapping the southern sky in unprecedented detail, ultimately hoping to decipher what may stand as the most bewildering phenomenon of our expanding universe.

    In March, DES applied to the Large and Long Program at the Gemini Observatory, a program meant to foster scientific exploration through global collaboration. Although the Gemini Observatory has existed since 2000, the Large and Long Program launched just last year as another means to probe the shrapnel of the big bang. It offers time on two of the world’s finest telescopes, one located atop an 8,900-foot mountain in the Chilean Andes (Gemini South) and the other on Mauna Kea, Hawaii (Gemini North).

    Gemini North telescope
    Gemini North

    Gemini South telescope
    Gemini South

    Just last month, co-leader of the Strong Lensing Science Working Group at DES, Liz Buckley-Geer, received the email she’d been waiting for: Spread over the next three years, DES had been awarded a lofty total of 276 hours on Gemini South.

    “Because we were asking for such a big block of time I really didn’t think we had much of a chance,” Buckley-Geer said. “I was pretty gobsmacked when I got the email two weeks ago.”

    With a hefty 8.1-meter mirror, the Gemini telescope is twice as large as the telescope on which DECam is currently mounted. But DES scientists don’t plan to take new images with Gemini South. DECam images are plenty clear and show high-quality snapshots of galaxies and galaxy clusters. Instead of imaging, DES scientists will use an instrument called a spectrograph to further inspect the images and, in some cases, confirm a rare phenomenon called strong lensing.

    DECam
    DECam

    One of five methods DES uses to explore dark energy, strong lensing is the bending of light from a distant galaxy, or source, due to the gravitational influence of a massive foreground object, or lens. Lensing changes the observed shape of the distant galaxy and intensifies brightness. To find these strong lensing systems in the DECam images, DES scientists look for objects that look distorted, often appearing as long bright arcs, multiple blue knots or, in the rarest cases, an Einstein ring. DES will focus on certain classes of strong lenses that can be used to study dark energy.

    “The strong lenses provide a kind of peephole to the more distant, fainter universe that wouldn’t be available if the lenses weren’t there,” said DES Operations Scientist Tom Diehl.

    But what appear to be strong lenses are not always so. To separate the lenses from the impostors, scientists measure the redshifts of both the lens and the source. A true strong lens is one in which the source redshift is larger than the lens redshift.

    A redshift occurs when light wavelengths increase, or shift toward the red side of the electromagnetic spectrum. The measured redshift of a galaxy is related to the expansion of the universe as a function of time, and it allows DES scientists to calculate the distance to the object.

    To determine the redshift of a galaxy, the scientists will compare the spectrum of the obtained light with known features in the spectrum of various chemical compounds found on Earth. If the same features are seen in an observed spectrum from a distant source but occur at shifted wavelengths, then the redshift can be calculated.

    “The observations with Gemini will give us the redshifts of all these objects, and armed with that information we can move on to the next step,” Buckley-Geer said. “It’s not all the information we need, but it’s one piece of the jigsaw puzzle closer to understanding these system in relation to dark energy.”

    See the full article here.

    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.


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  • richardmitnick 9:25 am on April 4, 2014 Permalink | Reply
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    From Fermilab- “Frontier Science Result: Sloan Digital Sky Survey Sloan Digital Sky Survey and the cosmological constant” 


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

    Friday, April 4, 2014
    John Marriner

    The Sloan Digital Sky Survey supernova (SDSS SN) survey was born in 2004, when a team led by Fermilab’s Josh Frieman was approved as part of the first extension of the original survey. Frieman, now leader of the Dark Energy Survey, recognized that the wide-field-of-view Sloan telescope made it an ideal instrument to observe supernovae — extremely bright, exploding stars.

    The Sloan supernova project has resulted in more than 30 publications, including the recent paper of Betoule, et al, to be published in Astronomy and Astrophysics. It is the most precise analysis of supernova data to date.

    Stars in the type Ia class of supernovae explode with the same intrinsic brightness. Thus scientists can determine the distance to a supernova by measuring the apparent brightness as seen from Earth. The wavelength of distant light is shifted toward redder colors, and the amount of redshift reveals how long ago the light was emitted. Taken together, the measurements of the supernova brightness and redshift allow scientists to determine the size of the universe as a function of cosmic time.

    The Nobel Prize-winning discovery of [Saul] Perlmutter, Riess and Schmidt showed the expansion of the universe is now accelerating, not decelerating from gravity as expected. The phenomenon is called dark energy, and its properties are often described in terms of the ratio of its pressure to its density — a ratio called w. [Albert] Einstein’s equations for general relativity include the possibility of a value called the cosmological constant, which could provide the mathematical description of dark energy if the value of w is exactly -1. Any other result requires some other modification to Einstein’s equations.

    The Sloan supernova survey and a similar, higher-redshift survey known as the Supernova Legacy Survey formed a “joint lightcurve analysis” group (JLA) to analyze supernova data from both surveys. The full SDSS SN sample and essential improvements in analysis technique produced the new, precise result.

    chart
    The allowed region for cosmological parameters according the recent analysis of supernova data combined with the previously published results from the ESA/Planck satellite data.

    The figure above shows the result of the JLA analysis and illustrates the effectiveness of combining the supernova data with data from the Planck satellite, which has provided the most precise measurement of the cosmic microwave background. Along the horizontal axis, labeled ΩM, is the fraction of the universe that consists of ordinary matter, and w is the parameter that describes dark energy. The color contours show the experimentally allowed region for these cosmological parameters. The gray region shows the combination of the Planck and the JLA results.

    The measured value of w is -1.018 ± 0.057 and is consistent with Einstein’s cosmological constant. Nevertheless, it is still only a step towards understanding dark energy.

    See the full article here.

    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.


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  • richardmitnick 1:14 pm on February 25, 2014 Permalink | Reply
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    From Fermilab: “To catch a falling asteroid: Dark Energy Camera scientists locate object passing Earth” 


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

    Tuesday, Feb. 25, 2014
    Leah Hesla

    For seven minutes earlier this month, two Fermilab physicists moonlighted as astronomers who, like the Men in Black, were positioned to protect the Earth from the scum of the universe.

    On Feb. 3, Alex Drlica-Wagner and Steve Kent were in Chile taking data for the Dark Energy Survey when they received an email stating that a satellite telescope had picked up signs of a potentially hazardous asteroid, one whose orbit might soon meet with Earth’s.

    three
    This Dark Energy Survey observing team was on shift at the Dark Energy Camera in Chile when they got the call to check out a potentially hazardous asteroid. From left: Steve Kent (Fermilab and University of Chicago), Alex Drlica-Wagner (Fermilab) and Hernan Tirado, telescope operator at the Cerro-Tololo Inter-American Observatory, where DECam is housed. Photo: Sara Barber, University of Oklahoma

    The message had come from a scientist at the Jet Propulsion Laboratory. Bad weather in the northern hemisphere had foiled attempts by JPL’s two go-to cameras to photograph the asteroid, hindering the lab’s ability to predict its orbit. Could the Dark Energy Camera take a bit of time off from its usual task of imaging distant galaxies to take pictures of this near-Earth object?

    DECam
    DECam

    “We know about thousands of these asteroids,” said Kent, SCD. “Of course, one we didn’t know about hit Russia last year, so there’s a lot of interest.”

    Since the asteroid was new on the orbital block, astronomers had only a rough idea of where it was headed. They did know it would soon pass in line with the sun and thus be difficult to spot in photographs.

    “If we didn’t follow up on it within two days, they weren’t going to be able to follow it up anytime soon,” said Drlica-Wagner of Fermilab’s Center for Particle Astrophysics. “Because of the weather and the uncertainty of the predictions, DECam was the only thing that could pull it off.”

    Given Chile’s clear skies and DECam’s large field of view, Drlica-Wagner and Kent were fairly confident they could catch the asteroid on camera in five takes, even if its predicted location was only an estimate. They punched in the coordinates JPL gave them and took their shots. Seven minutes later, they had photos.

    The asteroid turned up in all five, though it wasn’t immediately apparent. The images had to be processed by the National Optical Astronomy Observatory in Tucson, Ariz., and coordinates submitted to the Minor Planet Center in Cambridge, Mass., to figure out the orbit. The results were then sent to JPL.

    The asteroid looked just like the faint stars that it shared the photos with, except for one characteristic — it appeared in different positions in the five images, just the way a cartoon dot would move in a flipbook.

    After combining the pictures with the satellite data, the asteroid-tracking crew brought good news.

    “People shouldn’t be particularly worried,” Drlica-Wagner said. At its closest approach to Earth on March 1, newly discovered Apollo-class asteroid 2014 BE63 will be 18 million miles away.

    The Dark Energy Camera scientists were glad to come to the aid of fellow astronomers.

    “In astronomy there are always things that are time-critical in nature. People will say, ‘You’re at the telescope. Can you do something for me?'” Kent said. “It’s a bit of a tradition to help when you can.”

    He added jokingly, “In this case, saving the Earth was an extra factor, so we thought it was generous.”

    See the full article here.

    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.


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  • richardmitnick 11:53 am on February 21, 2014 Permalink | Reply
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    From Fermilab- “Frontier Science Result: Dark Energy Survey Cosmic shadows in the microwave light from the big bang” 


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

    Friday, Feb. 21, 2014
    Bradford Benson

    The cosmic microwave background [CMB] is the radiant heat left over from the big bang. It was emitted nearly 14 billion years ago, just 380,000 years after the big bang, and has traveled across literally the entire observable universe. This makes the CMB an ideal backlight to find the most massive, distant structures in the universe, in particular clusters of galaxies.

    CMB Planck ESA
    CMB from ESA’s Planck Spacecraft

    The most massive clusters consist of over 1,000 galaxies and have a total mass larger than 1 million billion suns. Even with its relatively impressive heft, when CMB photons pass through a cluster, only about 1 percent scatter off of gas in the cluster, but this is enough to create a distinctive “shadow” in the CMB, usually known as the Sunyaev-Zel’dovich effect.

    Clusters of galaxies are the largest gravitationally bound objects in the universe and are therefore important tracers of cosmic structure growth. The abundance of clusters over the history of the universe gives information about a variety of cosmological parameters, including the properties of dark energy. Earlier in the universe’s history, dark energy affected the abundance of clusters primarily through its effect on the growth of structure in the universe. Therefore, the abundance of clusters probes the dark-energy paradigm in a way that complements geometric probes such as the light from supernovae.

    The South Pole Telescope (SPT) and the Dark Energy Survey (DES), designed to find clusters of galaxies, are conducting overlapping surveys of the southern sky. The SPT finds a cluster through its distinctive shadow in the cosmic microwave background. DES finds clusters more traditionally by looking for over-densities of galaxies in optical images.

    South Pole Telescope
    The South Pole Telescope is funded through the National Science Foundation and the Department of Energy Office of Science.

    DES DECam
    DECam

    Each survey, which is designed to provide the largest catalog ever of massive, distant clusters, has an unprecedented combination of depth and area. The two methods have a strong complementarity and, in combination, are expected to provide significantly improved constraints on the evolution of dark energy via its effect on the growth of structure of the universe.

    The DES survey recently finished its first year of a five-year survey on Feb. 9. Preliminary analyses of a subset of the DES data have already yielded a cluster catalog with nearly 1,000 clusters. The SPT measurements of the Dark Energy Survey clusters show the distinctive shadows in the cosmic microwave background expected from the Sunyaev-Zel’dovich effect. Even with this early data, the measurements confirm that: 1) DES is successfully finding very massive, distant clusters and 2) the SPT is measuring the distinctive cluster shadow in the cosmic microwave background with a spectral distortion at the level expected from theory.

    The data is just a sign of things to come from the final survey, confirming the power of the South Pole Telescope and Dark Energy Survey data sets to find and characterize clusters and giving us a powerful new tool for understanding dark energy.

    See the full article here.

    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.


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  • richardmitnick 1:31 pm on January 28, 2014 Permalink | Reply
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    From Fermilab: “Toward a new dark-energy detector” 


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

    Tuesday, Jan. 28, 2014
    Leah Hesla

    The power of the 570-megapixel Dark Energy Camera lies in its ability to capture celestial objects millions of light-years away. Scientists are now working toward developing an instrument for characterizing these stars and galaxies in greater detail.

    DECam
    DECam

    Scientist Juan Estrada, PPD, is currently leading a Fermilab team to develop a large instrument using detectors called MKIDs, short for microwave kinetic inductance detectors. In the coming years, they’ll use it to obtain more information about the astronomical objects already detected by the Dark Energy Camera, pointing it into the night sky to capture more information about those objects’ light.

    The team builds on the work of a University of California, Santa Barbara group, led by Ben Mazin, which developed MKIDs for the visible and infrared spectrum.

    “These are small detectors,” Estrada said. “We’d like to convert this technology into something for a large instrument for cosmology.”

    The Dark Energy Camera is outfitted with 74 charge-coupled devices, better known as CCDs, and its optical filters divide the light from far-off galaxies or stars into one of five spectral ranges. When a CCD gets a hit from one of the photons from the split-off light, it sends a small signal saying that the light in that filter’s range of wavelengths has come through. The data from the five filters are then reassembled into a color picture of the galaxy or star, much the way your computer monitor layers red, green and blue pixels to generate full-color images.

    Thus DECam’s filter-and-CCD system gives scientists the rough spectral make-up of an astronomical object.

    ccd
    A prototype of the Dark Energy Survey camera, DECam. The front ring holds the detecting CCDs and is 45cm in diameter. (Credit: Fermilab)

    An MKID, however, would enhance that five-color rendering many times over. When struck by a visible photon, it produces a flood of so-called quasiparticles, allowing the wavelength for every single photon hitting the MKID to be precisely measured. That, in turn, leads to color images of astronomical objects without the use of optical filters. The higher the photon’s energy — or the more towards the violet end of the spectrum it is — the more particles it produces.

    MKIDs, which use superconducting material, must be very cold to be able to detect photons. In testing the current MKID-based prototype instrument, Estrada’s team recently brought it to a temperature of 33 millikelvin — the lowest temperature ever achieved on site at Fermilab.

    Over the next several years, the team hopes to create an MKID prototype instrument that can be installed in a telescope on a mountaintop next to DECam for testing. This means assembling it with a compatible mechanical design and high-bandwidth digital processing system.

    If all goes well, they can look realistically to constructing instruments installed with MKIDs and, conceivably, with 100,000 light channels. That’s 20 times more channels than the next-generation technology represented by the Dark Energy Spectroscopic Instrument, a future spectrograph that Fermilab is now helping to construct.

    “We are still some distance away from having a full-on instrument,” Estrada said. “But we are taking the initial steps that would put us closer to this very ambitious goal.”

    See the full article here.

    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.


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  • richardmitnick 4:35 pm on December 3, 2013 Permalink | Reply
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    A Rare Post from The Dark Energy Survey: “CSI: Early Universe” 

    Dark Energy Icon

    Det. B. Nord [FNAL]

    For this installment of Cosmic Scene Investigation, we travel to one of the earliest collisions of large-scale structures in the known universe.

    csi
    From DES. Credits in text.

    el gordo
    Another view. El Gordo consists of two separate galaxy subclusters colliding at several million
    kilometres per hour.
    Credit: ESO/SOAR/NASA

    A splatter of red (denoting galaxies) lies at the center of this image, and extends toward the lower left. These are the remnants of a cosmic collision. Aeons ago, one group plunged through another at millions of miles per hour, leaving in its wake a wreckage. The galaxy cluster ‘El Gordo‘ is all that remains of this raucous event, which took place less than a billion years after the universe started.

    From the deserts of Chile, the Atacama Cosmology Telescope was the first to detect this prodigious system. NASA’s Chandra X-ray Observatory, the [ESO] Very Large Telescope, and NASA’s Spitzer Telescope have also collected forensic evidence across the energy spectrum, from the infrared to the X-ray. All put together, we see a system similar to the infamous Bullet Cluster: a pair of clumps converted to a churning, violent amalgam of hot gas, dust and light.

    An extremophile in the truest sense, El Gordo is the earliest-occurring cluster of its caliber. Its hot gas is burning at 360 million degrees Fahrenheit (200 million degrees Celsius), and it weighs in at a million billion times the mass of Earth’s sun. Compare this to the Virgo cluster of galaxies, the celestial city that holds our Milky Way and its neighbors. El Gordo’s mass is about the same, but it is over a hundred times hotter.

    Dark energy is the name given to that substance, that energy, that is making spacetime spread out faster and faster. In the early universe, the small chunks that make up El Gordo were able to overcome dark energy (if it even existed then) and move toward each other to produce this cosmic crash scene. How many more like it are out there? The case remains open.

    See the full article here.

    The Dark Energy Survey (DES) is designed to probe the origin of the accelerating universe and help uncover the nature of dark energy by measuring the 14-billion-year history of cosmic expansion with high precision. More than 120 scientists from 23 institutions in the United States, Spain, the United Kingdom, Brazil, and Germany are working on the project. This collaboration [has built] an extremely sensitive 570-Megapixel digital camera, DECam, and will mount it on the Blanco 4-meter telescope at Cerro Tololo Inter-American Observatory high in the Chilean Andes. Starting in Sept. 2012 and continuing for five years, DES will survey a large swath of the southern sky out to vast distances in order to provide new clues to this most fundamental of questions.


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  • richardmitnick 5:30 am on September 28, 2013 Permalink | Reply
    Tags: , Dark Energy Survey, ,   

    From Fermilab- “Frontier Science Result: Dark Energy Survey Through a lens darkly (and strongly)” 


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

    Friday, Sept. 27, 2013
    Huan Lin

    The Dark Energy Survey collected more than 34,000 exposures during its science verification (SV) phase, from November 2012 to February 2013. It also began its first official season of observations on Aug. 31. Among the millions of astronomical objects imaged by DES so far, there are rare instances of “strong lensing” systems, where the effects of general relativity, Einstein’s theory of gravity, are demonstrated in visually striking fashion.

    Dark Energy Survey

    When a foreground “lens” object is by chance very closely aligned on the sky with a much more distant background “source” object, the light from the source may be significantly deflected as it passes by the lens, due to the gravity of the lensing object’s mass. This strong lensing effect leads to big distortions in the appearance of the source object: An otherwise faint and fuzzy single distant background galaxy may be transformed instead into a long bright arc, maybe into multiple blue knots or, in the rarest cases, into a so-called Einstein ring (see figure).

    de
    Examples of strong lensing systems imaged in the DES science verification (SV) data. Previously known strongly lensed, bluish-colored arcs are visible in the DES images of three rich galaxy clusters. Top row, from left: Bullet Cluster, RXC J2248.7-4431 and El Gordo. A nearly complete Einstein ring is visible in another cluster lensing system (bottom left), which was previously found by Fermilab scientists. Finally, two new candidate systems discovered in the DES SV data are also shown: one with a giant blue arc (bottom middle) and one with multiple blue images (bottom right).

    This wide variety in appearance of strongly lensed images is a consequence of the complexities of the lensing mass, which can range from an individual galaxy to a rich cluster of many galaxies, together with the much more massive dark matter halos in which the (luminous) galaxies reside. Studies of strong lensing systems can thus reveal to us properties of the distribution of dark matter that accompanies galaxies and galaxy clusters. Moreover, in addition to galaxy clusters, weak lensing, large-scale structure and supernovae — the four primary dark-energy probes used by DES — strong lensing may ultimately provide yet another way to study dark energy. For example, cosmological parameters, including dark energy, will affect the abundance and frequency of strong lensing systems and hence influence how many such systems we’ll find in DES.

    You can view recent images taken by the Dark Energy Survey at the new site Dark Energy Detectives.

    See the full article here.

    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.


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