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16 December 2008 |
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Study of galaxy clusters detects growth-stifling dark energy, The University of Chicago News Office |
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1 December 2008 |
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Luce fellow works to add new knowledge about universe, The University of Chicago Chronicle |
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28 August 2008 |
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NASA names gamma-ray telescope after Enrico Fermi, The University of Chicago News Office |
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28 July 2008 |
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$270,000 in seed grants awarded to joint Fermilab - University of Chicago Strategic Collaborative Initiatives, The University of Chicago News Office |
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17 July 2008 |
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A $20 million gift, an ambitious agenda in science, The University of Chicago News Office |
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16 June 2008 |
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Slacker Astronomy: Juan Collar and Detecting Dark Matter, Slacker Astronomy |
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12 June 2008 |
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University to create Center for Physical, Computational Sciences, The University of Chicago Chronicle |
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6 May 2008 |
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Postal Service pays tribute to astronomer Edwin Hubble, The University of Chicago News Office |
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30 April 2008 |
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The Hubble Stamp, Chicago Public radio |
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7 April 2008 |
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Astronomy professor observes opportunity to teach his class from Andes mountaintop, The University of Chicago Chronicle |
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29 March 2008 |
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South Pole telescope peers heavenward for dark energy, Los Angeles Times |
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28 March 2008 |
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Slacker Astronomy's Podcast interview with Brant Robertson, Slacker Astronomy |
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26 March 2008 |
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Free lecture series to peer behind exotic claims about universe, The University of Chicago News Office |
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26 February 2008 |
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Sloan Digital Sky Survey Changes the Face of Astronomy, The University of Chicago News Office |
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14 February 2008 |
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COUPP experiment tightens limits on dark matter, Fermilab Press Release |
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12 February 2008 |
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The Kavli Foundation News, Astrophysics: Eyeing Dark Energy, The Kavli Foundation |
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21 January 2008 |
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Science magazine's top 10 breakthroughs of the year, ARS technica |
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12 January 2008 |
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New detector will improve method for gathering data on cosmic rays, The University of Chicago Chronicle |
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2 January 2008 |
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Hot on the Trail of Cosmic Rays, Space.com |
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1 January 2008 |
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A cold, hard look at one of science's hottest mysteries, Chicago Tribune |
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16 December 2008
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by Steve Koppes, Study of galaxy clusters detects growth-stifling dark energy
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Like referees with different vantage points concurring on an important call in a tight football game, an international team of cosmologists has independently confirmed the accelerating expansion of the universe.
A decade ago, astronomers studying the relatively uniform brightness of exploding stars to estimate cosmic distances discovered that the expansion of the universe appeared to be accelerating. Gravity should have been causing the expansion, which followed the big bang, to become slower with time. This gave rise to the mystery of dark energy, the unknown force theoretically responsible for the acceleration.
Now cosmologists, including the University of Chicago's Andrey Kravtsov, have come to the same conclusion via a completely different method: tracing the evolution of galaxy clusters. Often containing hundreds of galaxies, these clusters are the largest visible masses in the cosmos that are held together by gravity.
"This result could be described as 'arrested development of the universe,'" said Alexey Vikhlinin of the Smithsonian Astrophysical Observatory in Cambridge, Mass., who led the research. "Whatever is forcing the expansion of the universe to speed up is also forcing its development to slow down."
The cosmologists will publish their findings in the Feb. 10 issue of the Astrophysical Journal. They announced their findings during a Dec. 16 news conference organized by the National Aeronautics and Space Administration.
Vikhlinin and his colleagues used NASA's Chandra X-ray Observatory to observe the hot gas in dozens of galaxy clusters. Some of these clusters are relatively nearby, while others are more than halfway across the universe. The observatory is named for the late University of Chicago Professor Subrahmanyan Chandrasekhar, who received the 1983 Nobel Prize in Physics.
The galaxy cluster data align with a universe dominated by dark energy. It is more difficult for galaxy clusters to grow when space is stretched, as caused by dark energy. Dark energy is invisible, but the cluster evolution traced by the Chandra observations clearly reveals the force's presence via its influence on evolution of galaxy clusters in the last six billion years.
Computer simulations of galaxy cluster evolution performed by University of Chicago alumnus Daisuke Nagai, Ph.D.,'05, now an Assistant Professor at Yale University, and Andrey Kravtsov, Associate Professor in Astronomy & Astrophysics at the University of Chicago, provided the theoretical underpinning for the analysis and interpretation of the Chandra data. The current paper on cosmological constraints is the most recent in a series of related studies that Vikhlinin, Kravtsov and Nagai have published together in the last three years.
The team's results strengthen the evidence that dark energy is the cosmological constant, a steady force operating pervasively throughout the universe. "This is remarkable because there is no particular known reason why it should be so," said Kravtsov, who is also a senior member of the Kavli Institute for Cosmological Physics at the University of Chicago.
Einstein considered the cosmological constant to be one of his greatest blunders. He introduced the factor into his theory of general relativity to accommodate a stationary universe, the dominant idea of his day. But his constant fits nicely into the modern concept of an expanding universe, a product of the big bang theory and all existing observations.
Although the constant is a leading candidate to explain dark energy, theoretical work suggests that it should be about 10120 (1 followed by 120 zeroes) times larger than observed. This led scientists to seek alternatives to general relativity, including theories involving hidden dimensions.
"A lot more testing is needed, but so far Einstein's theory is looking as good as ever," Vikhlinin said.
NASA's Marshall Space Flight Center in Huntsville, Ala., manages the Chandra program for NASA's Science Mission Directorate in Washington, D.C. The Smithsonian Astrophysical Observatory controls Chandra's science and flight operations from Cambridge, Mass.
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The University of Chicago News Office
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1 December 2008
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by Greg Borzo, Luce fellow works to add new knowledge about universe
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Determined to help unravel some of the mysteries of the universe, Fields is working with Juan Collar, Associate Professor in Physics, on an experiment to determine whether neutrinos are their own antimatter. An antimatter particle has the same mass but the opposite charge as its counterpart particle. Most particles have distinct antiparticles, but photons, for example, are their own antiparticle.
In another experiment, Fields, Collar and his colleagues at the University and collaborators at other universities are attempting to observe Weakly Interactive Massive Particles, commonly referred to as WIMPs. That can be pretty tough since no one knows whether they exist.
WIMPs are thought to be dark matter, an invisible form of matter that emits little or no detectable radiation. Dark matter is not well understood, but it may be largely composed of a variety of subatomic particles that have not yet been discovered.
“As dark matter candidates, WIMPs should be around us all the time,” Fields said. “WIMPs usually pass right through matter, but scientists theorize that if one scattered off an atomic nucleus, the nuclear recoil would excite electron hole pairs, which could be detected.”
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The University of Chicago Chronicle
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28 August 2008
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by Steve Koppes, NASA names gamma-ray telescope after Enrico Fermi
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NASA's Gamma-ray Large Area Space Telescope has joined the constellation of satellites named after University of Chicago scientists. Today, NASA announced that the Gamma-ray Large Area Space Telescope will be called the Fermi Gamma-ray Space Telescope.
"This satellite will collect gamma rays from the most energetic regions of our galaxy and beyond," said Simon Swordy, Director of the University of Chicago's Enrico Fermi Institute.
"Working in the Research Institutes building on Ellis Avenue in the late 1940s, Enrico Fermi produced the first quantitative ideas on how cosmic particles could reach the enormous energies needed to produce these cosmic-gamma rays. It is wonderful to hear that NASA has decided to dedicate this satellite to him."
NASA launched the telescope on a Delta II rocket on June 11. The telescope's mission is to collect data on black holes, gamma-ray bursts—the most powerful explosions in the universe—and other cosmic phenomena produced at extreme energies.
Fermi received the Nobel Prize in 1938 for his discovery of new radioactive elements produced by the addition of neutrons to the cores of atoms, and for the discovery of nuclear reactions brought about by slowly moving neutrons.
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The University of Chicago News Office
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28 July 2008
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by Lisa La Vallee, $270,000 in seed grants awarded to joint Fermilab - University of Chicago Strategic Collaborative Initiatives
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Scientists at Fermi National Accelerator Laboratory, the University of Chicago and Argonne National Laboratory have been awarded $270,000 for new and continued joint research projects through the University’s Strategic Collaborative Initiatives (SCI) program for Fermilab. The research projects cover a broad range of studies and include, in one case, collaboration with an Argonne scientist.
Proposals receiving SCI grants and their principal investigators are:
* "Fundamental Studies of the Interfacial Oxidation Chemistry of Niobium and the Influence Such Oxidation Has on High-performance Superconducting RF Materials," Steven J. Sibener, Carl William Eisendrath Professor, Department of Chemistry, and Director, The James Franck Institute, The University of Chicago; and Lance Cooley, SRF Materials Group Leader, Technical Division, Fermilab
* "The Development of Ultra-Fast Timing Detectors," Henry Frisch, Professor, Department of Physics and Enrico Fermi Institute; Erik Ramberg, Scientist II, Particle Physics Division, Fermilab, and Karen Byrum, Scientist, High Energy Physics Division, Argonne
* "Absolute Measurement of Air Fluorescence Yield for Ultra-High Energy Cosmic Rays," Paolo Privitera, Professor, Astronomy and Astrophysics, The University of Chicago; and Carlos Hojvat, Scientist II, Particle Physics Division, Fermilab
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The University of Chicago News Office
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17 July 2008
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by Steve Koppes, A $20 million gift, an ambitious agenda in science
The University of Chicago News Office
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16 June 2008
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Slacker Astronomy: Juan Collar and Detecting Dark Matter
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We bring you another fascinating cosmology interview with a genius over at the Kavli Institute for Cosmological Physics. This time we speak to Juan Collar, a name that I am, apparently, incapable of saying. He leads a group at Kavli which is pursuing several experimental approaches to detecting dark matter in the lab.
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Slacker Astronomy
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12 June 2008
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by Steve Koppes, University to create Center for Physical, Computational Sciences
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The University Board of Trustees has approved HOK as architect for the proposed Center for Physical and Computational Sciences. HOK, a firm with 26 regional offices worldwide, including one in Chicago, has completed several major science and technology projects in recent years.
The estimated $375 million center will encompass half a million square feet of new and renovated space on the west side of Ellis Avenue between 56th and 57th streets. The scientists who will move into the center currently work in multiple buildings that are either poorly connected or scattered across campus.
"It's difficult for the scientists to interact with one another, and now their work is more important than ever," said Robert Fefferman, Dean of the Physical Sciences Division.
The center will provide space for three departments: Astronomy & Astrophysics, Physics and Computer Science; and four physical sciences institutes: the Kavli Institute for Cosmological Physics, the Computation Institute, the Enrico Fermi Institute and the James Franck Institute. Construction is scheduled to begin in fall 2010, with completion in spring 2013.
"The departments and institutes serviced by this ambitious project are gems of the University. These units impact more than just research in the Physical Sciences," said Fefferman, the Max Mason Distinguished Service Professor in Mathematics and the College.
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The University of Chicago Chronicle
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6 May 2008
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by Steve Koppes, Postal Service pays tribute to astronomer Edwin Hubble
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Chicago unveiling of commemorative stamp honoring University of Chicago alumnus Edwin Hubble.
Edward "Rocky" Kolb, Professor and Chairman, Department of Astronomy and Astrophysics, University of Chicago
James Mruk, Manager, Public Affairs and Communications, Great Lakes Area of the United States Postal Service
In March, the U.S. Postal Service acknowledged some of the most impressive scientific achievements of the 20th century with the issue of its second series of American Scientists stamps. Astronomer Edwin Hubble (1889-1953), alumnus of the University of Chicago (S.B., 1910, Ph.D., 1917), played a pivotal role in deciphering the vast and complex nature of the universe. His meticulous studies of spiral nebulae proved the existence of galaxies other than our own Milky Way, paving the way for a revolutionary new understanding that the cosmos contains myriad separate galaxies or “island universes.”
The local unveiling of the Edwin Hubble stamp will take place before the weekly colloquium of the University’s Department of Astronomy and Astrophysics.
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The University of Chicago News Office
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30 April 2008
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The Hubble Stamp
Chicago Public radio
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7 April 2008
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by Steve Koppes, Astronomy professor observes opportunity to teach his class from Andes mountaintop
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Michael Gladders presented two lectures to his "Astronomy and Astrophysics of Stars" class last year from a mountaintop in the Andes Mountains of South America.
Gladders had to be at the Las Campanas Observatory in the Andes to test an instrument for the twin 6.5-meter Magellan Telescopes in October 2007, so he connected with his 64 students back on campus via an Internet audio-video connection.
"I looked upon it as an opportunity to bring the class into something at a level where normally they’d never have that experience," said Gladders, Assistant Professor in Astronomy & Astrophysics and the College.
Competition is keen among astronomers for viewing time on telescopes at major observatories like Las Campanas in Chile. The applicants fortunate enough to receive time usually accept whatever dates they are offered.
"There's not a lot of flexibility," Gladders said.
Gladders began working on the instrument he calls the "image slicer" three years ago, while he served as a postdoctoral fellow at Carnegie Observatories. But his colleagues refer to it as GISMO—the Gladders Image-Slicing Multi-Slit Option. "The design was entirely Mike's," said Alan Dressler of the Carnegie Observatories, who coined the device's name.
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The University of Chicago Chronicle
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29 March 2008
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by William Mullen, South Pole telescope peers heavenward for dark energy
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Anywhere on Earth this would be a big telescope, as tall as a seven-story building, with a main mirror measuring 32 1/2 feet across. But here at the South Pole, it seems especially large, looming over a barren plain of ice that gets colder than anywhere else on the planet.
Scientists built the instrument at the end of the world so they can search for clues that might identify the most powerful, plentiful but elusive substance in the universe: dark energy.
First described just nine years ago, dark energy is a mysterious force so powerful that it will decide the fate of the universe. Having already overruled the laws of gravity, it is pushing galaxies away from one another, causing the universe to expand at an ever faster rate.
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Los Angeles Times
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28 March 2008
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Slacker Astronomy's Podcast interview with Brant Robertson
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We have a new show! Doug and I had a great chat with Brant Robertson, who is a Spitzer Fellow doing research at The Kavli Institute for Cosmological Physics. Brant is a theoretical astrophysicist involved with computer simulations of the evolution of galaxies.
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Slacker Astronomy
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26 March 2008
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by Steve Koppes, Free lecture series to peer behind exotic claims about universe
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A series of 10 free lectures at the University of Chicago will explore how scientists can talk sensibly about the beginning of the universe, or phenomena at exceedingly small scales.
"Seeing and Believing: Detection, Measurement and Inference in Experimental Physics," is the title of this year's Arthur Holly Compton Lectures, sponsored each spring and fall by the University's Enrico Fermi Institute. The 67th series of these public lectures will begin Saturday, April 5, and will be held each Saturday through June 14 (except for May 24, when there will be no lecture). The lectures will be given from 11 a.m. to noon in Room 106 of the Kersten Physics Teaching Center, 5720 S. Ellis Ave.
Compton Lectures are intended to make science accessible to a general audience and to convey the excitement of new discoveries in the physical sciences. Delivering the lectures this spring will be Kathryn Schaffer, a postdoctoral fellow at the Kavli Institute for Cosmological Physics and the Enrico Fermi Institute at the University of Chicago.
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The University of Chicago News Office
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26 February 2008
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by Steve Koppes, Sloan Digital Sky Survey Changes the Face of Astronomy
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Two hundred and seventy two stars gave their lives for the photo spread on cosmic explosions that graced pages 80 and 81 of the March 2007 National Geographic.
Ben Dilday, University graduate student in Astronomy & Astrophysics, assembled these images of exploding stars from observations the Sloan Digital Sky Survey collected in 2005 and 2006. The images come in the vanguard of the SDSS II (Sloan Digital Sky Survey’s Phase Two), which focuses, in part, on supernovas. During its first phase, survey astronomers invented a new way of doing astronomy by dedicating a single telescope to mapping the universe in three dimensions.
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The University of Chicago News Office
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14 February 2008
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by Tona Kunz, Steve Koppes, and Kathy Borlik, COUPP experiment tightens limits on dark matter
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Scientists working on the COUPP experiment at the Department of Energy's Fermi National Accelerator Laboratory today (February 14) announced a new development in the quest to observe dark matter. The Chicagoland Observatory for Underground Particle Physics experiment tightened constraints on the "spin-dependent" properties of WIMPS, weakly interacting massive particles that are candidates for dark matter. Their results, combined with the findings of other dark matter searches, contradict the claims for the observation of such particles by the Dark Matter experiment (DAMA) in Italy and further restrict the hunting ground for physicists to track their dark matter quarry.
The COUPP experiment also proved that dusting off an old technology of particle physics, the bubble chamber, offers extraordinary potential as a tool in the search for dark matter.
"Our first results are extremely encouraging, and bubble-chamber technology is eminently scale-able," said Juan Collar, a University of Chicago professor and spokesman of the COUPP collaboration, which includes 16 scientists and students from the University of Chicago; Indiana University South Bend; and DOE's Fermilab. "We expect that COUPP will soon have a sweeping sensitivity to dark matter particles, simultaneously exploring both spin-dependent and spin-independent mechanisms for dark matter interaction. This is just one of the aspects that set our experiment apart from the competition."
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Fermilab Press Release
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12 February 2008
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The Kavli Foundation News, Astrophysics: Eyeing Dark Energy
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Something is pulling the universe apart. What is it, and where will it take us from here? Scientists at the Kavli Institute for Cosmological Physics, University of Chicago, seek answers to those questions with the newly-commissioned South Pole Telescope.
Frigid and bone-dry, with six straight months of night each year, the South Pole is a forbidding place to live or work. But for largely the same reasons, it’s one of the best spots on the planet for surveying the faint cosmic microwave background (CMB) radiation left over from the Big Bang. The 10-meter microwave South Pole Telescope (SPT), which began operating in February 2007, is studying the CMB to gather clues about the birth, evolution and eventual fate of the universe.
The SPT project, led by researchers at the Kavli Institute for Cosmological Physics, University of Chicago, aims to help solve one cosmological mystery in particular – that of dark energy. Little is known about this force, other than that it works against gravity and appears to have sped up the expansion of the universe. Unlike energy as we know it (and measure it), dark energy does not seem to act through any of the fundamental forces of nature other than gravity. It can’t be detected directly, for instance, through light or other manifestations of the electromagnetic force. The evidence for dark energy is indirect. Its existence was first posited in 1998 by scientists seeking to explain unexpected data from distant supernovae. Since then, research using the Hubble Space Telescope and other instruments has traced the impact of dark energy to about nine billion years ago, when the universe was five billion years old and galaxies started flying away from one another at a faster pace.
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The Kavli Foundation
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21 January 2008
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by Matt Ford |, Science magazine's top 10 breakthroughs of the year
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Origin of Cosmic Bullets: It has been known since the 1960s that the Earth is bombarded by high energy cosmic particles. These particles are smaller than atoms yet hit the Earth with the force of a golf ball landing on a fairway - that is an energy level 100 million times higher then any particle accelerator has been able to achieve to date. The question of their origin may have been solved this year by researchers at the Pierre Auger Observatory in Argentina. Their answer: these particles come from active galactic nuclei, supermassive black holes at the center of some galaxies. However, without a mechanism to explain how these particles, protons in this case, reach these incredible energies (in excess of 60 EeV), the debate rages on.
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ARS technica
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12 January 2008
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by Steve Koppes, New detector will improve method for gathering data on cosmic rays
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Faint, fleeting blue flashes of radiation emitted by particles that travel faster than the speed of light through the atmosphere may help scientists solve one of the oldest mysteries in astrophysics.
For nearly a century, scientists have wondered about the origin of cosmic rays-subatomic particles of matter that stream in from outer space. "Where exactly, we don't know," said Scott Wakely, Assistant Professor in Physics and the College. "They're raining down on the atmosphere of the Earth, thousands of particles per second per square meter."
Recent results from the Pierre Auger Cosmic Ray Observatory suggest that the highest-energy cosmic rays may come from the centers of active galaxies. But the vast majority of the cosmic rays seen from Earth originate from unknown sources in the Milky Way galaxy. Tracking down these sources is crucial to developing a comprehensive understanding of the phenomenon, scientists say.
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The University of Chicago Chronicle
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2 January 2008
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by Jeremy Hsu, Hot on the Trail of Cosmic Rays
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The mysterious origins of cosmic rays that slam into the Earth's atmosphere could soon be revealed, thanks to a better ground-based sensor that costs less than balloons or satellites.
Cosmic rays are thought to come from either the center of the galaxy or a nearby supernova, and knowing which is true will help astrophysicists paint a more accurate picture of the cosmos.
"Cosmic rays are not a spectator phenomenon in the galaxy — they have a role in galactic dynamics," said Scott Wakely, a University of Chicago physicist. "To understand the galaxy in a full sense, you need to understand cosmic rays."
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Space.com
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1 January 2008
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by William Mullen, A cold, hard look at one of science's hottest mysteries
Chicago Tribune
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