The Institute for Gravitation and the Cosmos is a multidisciplinary institute of Penn State researchers dedicated to the study of the most fundamental structure and constituents of the Universe.
News and Events
- Thomson Reuter Science Watch has put on their website an analysis of the past ten years work on Gamma-Ray Bursts, the most energetic explosions in our universe, and in an interview with Peter Meszaros who is ranked #1 in the number of papers and total number of citations in GRB research. Peter's quote says: "Major questions of interest to all humanity, such as how the Universe looks at the earliests times and the largest distances we can probe, can be addressed with resources which require a minuscule fraction of the U.S. budget. International collaborations are invaluable in achieving such goals. Universities, both public and private, coupled to the resources of national labs and agencies, are ideal hothouses for providing the talent and manpower which can lead to momentous scientific results." The complete article is available at http://sciencewatch.com/ana/st/gamma/09junGamMesz/.
- The Center for Gravitational Wave Physics hosted the Neutron Stars Workshop on June 18-20, 2009 at The Atherton Hotel. The workshop featured invited presentations on selected topics and extensive discussion sessions between gravitational wave scientists, astronomers and astrophysicsts, and nuclear and condensed matter physicists. For more information, including speaker presentations, is available on the workshop webpage at http://gravity.psu.edu/events/neutron_stars/
- Edward Wilson-Ewing shared (with Hans Bantilan of Princeton) the award from the Topical Group in Gravitation of the American Physical Society for the best student presentation at the 12th Eastern Gravity Meeting, held in Rochester, New York, in June 2009. His talk was entitled "The Loop Quantum Cosmology of Bianchi I Models."
- For the occasion of Abhay Ashtekar's 60th birthday, AbhayFest will be hosted at Penn State's University Park campus during June 4-6, 2009. The program will provide a broad perspective on research in classical general relativity, diverse approaches to quantum gravity and other related areas. Registration and conference information for AbhayFest can be found on the Institute's Events page.
- Professors Doug Cowen and Tyce DeYoung lead a group of postdoctoral researchers, graduate students and undergraduates performing research with the IceCube
experiment at the South Pole. A recent article published by their collaboration was featured in Physical Review Letters "This Week in Physics" website.
(http://physics.aps.org/synopsis-for/10.1103/PhysRevLett.102.201302)
"In the search for dark matter, among the most interesting candidates is the neutralino, a neutral particle, predicted in supersymmetric extensions of the standard model, which interacts only weakly with other matter. Since the neutralino is expected to be stable, it may be possible to find particles that are relics of the early universe.
"Theorists have predicted that the sun's gravity can trap neutralinos, which could collect in its center and then annihilate each other. The standard-model particles created by these annihilations could subsequently decay, producing high-energy neutrinos that could escape from the sun and be detected on earth. Based on searches for these neutrinos, the IceCube Collaboration has now reported in Physical Review Letters new limits on neutralino annihilations in the sun.
"The IceCube neutrino detector is located between 1.5 and 2.5 km beneath the Antarctic ice, to reduce background events from cosmic rays. When muon neutrinos from the sun interact with the ice, they create relativistic charged particles (muons and showers of hadrons) that produce Cherenkov light, which is picked up by the detector. In an experiment lasting more than three months, no excess of neutrinos from the direction of the sun was detected. The experimentalists have therefore placed stringent limits on neutralino annihilations in the sun—a factor of 6 improvement over some previous limits - and from these, limits on the cross section for neutralino-proton interactions for neutralinos with masses above 250 GeV. These results narrow the possibilities for dark matter." (Stanley Brown, Physical Review Letters, from http://physics.aps.org/synopsis-for/10.1103/PhysRevLett.102.201302)
- Graduate student Tyler Anderson has received a two-year graduate fellowship from the Pennsylvania Space Grant Consortium to further his work on the NASA-supported CREAM (Cosmic Ray Energetics And Mass) balloon-borne experiment to study very high-energy cosmic rays and measure their elemental abundances. This provides important clues on high-energy astrophysical processes in the Galaxy, such as particle acceleration in supernova remnants. The CREAM high-altitude balloon flights take place annually over Antarctica, where Tyler traveled in support of the 2008/09 flight campaign. Tyler works in the group of Professor Stephane Coutu.
- Gabriel Caceres received a NSF Graduate Research Fellowship. Gabe has just finished his first year as a graduate student in the Astronomy and Astrophysics department and he is presently working on dark matter related topics with Irina Mocioiu. His research interests lie in theoretical particle astrophysics, particularly involving dark matter. Gabe's current work involves phenomenological studies of indirect detection signals, meaning the search for particles created in dark matter annihilations. These can involve local sources such as detecting neutrinos originating from dark matter in the Sun, or farther astrophysical sources such as the Galactic Center or extragalactic objects, from which one could detect, for example, gamma rays.
- The most distant cosmic explosion ever seen has been discovered by an international team, which includes astronomers at Penn State, using NASA's Swift satellite and several large telescopes at sites around the globe. The explosion, dubbed GRB 090423, is a gamma-ray burst from a star that died when the universe was 630 million years old – less than 5 percent of its present age. "The burst most likely arose from the explosion of a massive star," said Derek Fox, an assistant professor of astronomy and astrophysics at Penn State. "We're seeing the demise of a star - and probably the birth of a black hole - in one of the universe's earliest stellar generations." Complete article available at http://www.science.psu.edu/alert/Fox4-2009.htm.
- Meagan Lang was awarded the Gerard A. Hauser Award for the best overall presentation in the area of undergraduate research in the 2009 Penn State
Undergraduate Research Symposium. Meagan's poster presentation, "Improving Real-Time Gravitational Wave Astronomy" described the development and operation
of a new LIGO data analysis pipeline that is capable of identifying the detailed waveforms of gravitational waves on a network of detectors.
Karan Jani was awarded First Prize in the Physical Sciences category of the 2009 Penn State Undergraduate Research Symposium. His presentation, "Pointing Space Based Gravitational Wave Telescope," summarized his work on how the initial orientation of the proposed Laser Interferometer Space Antenna (LISA) detector affects its sensitivity to different gravitational wave sources. In addition, Karan was also selected as one of two finalists for the 2009 Vanderbilt Prize for Undergraduate Research in Physics and Astronomy. The Vanderbilt Prize is awarded following a nation-wide competition. Karan's entry, based on his research at Penn State was entitled "The Effect of Initial Orientation of the Laser Interferometer Space Antenna on its Sensitivity Pattern."
New Research Limits Big Bang's Output of Gravity Waves
A significant advance in our understanding of the early evolution of the universe has been achieved by a team of scientists associated with the Laser Interferometer Gravitational-Wave Observatory (LIGO) Scientific Collaboration and the Virgo Collaboration. The team's results appeared in the August 20, 2009 issue of the journal Nature. The gravitatioaal-wave scientists, including Lee Samuel Finn, a Penn State professor of physics and of astronomy and astrophysics, and Benjamin Owen, a Penn State professor of physics, have put new contraints on the details of how the universe looked in its earliest moments. Analysis of the team's data, taken from 2005 to 2007, has set the most stringent limits yet on the amount of gravitational waves that could have come from the Big Bang.
"Our results are a major step toward the detection of primordial gravitational waves - ripples in the fabric of space and time - that were created as the universe expanded in its earliest moments," said Finn, who has been a member of the LIGO Scientific Collaboration since its inception. More....
