KICP Seminars & Colloquia
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KICP Seminars & Colloquia, Fall 2001 Seminar schedule for Fall 2001October 5, 2001 Friday noon seminar | Michael Turner University of Chicago | How CDM explains Milgrom's Law | October 12, 2001 Friday noon seminar | Ben Metcalf IoA | The Dark Galaxy Problem and the Effects of Substructure on Gravitational Lenses [Abstract] | October 19, 2001 Friday noon seminar | Jasper Kirkby CERN | Are cosmic rays a cause of climate change? [Abstract] | November 2, 2001 Friday noon seminar | Eric Gawiser UCSD | Towards a Complete Picture of Damped Lyman Alpha Systems [Abstract] | November 7, 2001 Wednesday colloquium | Frederick Lamb University of Illinois | Using the High-Frequency X-Ray Oscillations of Neutron Stars and Black Holes to Probe Fundamental Physics | November 9, 2001 Friday noon seminar | Scott Wakely University of Chicago | Cosmological Insights from TeV Gamma Rays [Abstract] | November 14, 2001 Wednesday colloquium | Pierre Sokolsky University of Utah | Observation of Structure in the Cosmic Ray Spectrum below the GKZ-cutoff Energy by the HiRes Detector | November 16, 2001 Friday noon seminar | Greg Huey Queen Mary | Inflation, Braneworlds and Quintessence [Abstract] | November 27, 2001 Wednesday colloquium | James Bullock Ohio State University | Dark Halos and Galaxy Formation | November 28, 2001 Wednesday colloquium | Alexei Khokhlov Naval Research Laboratory | Progress in Three-Dimensional Modeling of Type la Supernova Explosions | November 30, 2001 Friday noon seminar | Christian Armendariz-Picon University of Chicago | k-Essence and late time cosmic acceleration [Abstract] | December 7, 2001 Friday noon seminar | Ravi Sheth FNAL | Large scale structure and voids [Abstract] | December 12, 2001 Wednesday colloquium | Edward Witten Institute for Advanced Study | The Dark Energy Problem |
COLLOQUIA - November 7, 2001 | 3:30 PM | RI 480 | Wednesday colloquium
Using the High-Frequency X-Ray Oscillations of Neutron Stars and Black Holes to Probe Fundamental Physics Frederick Lamb, University of Illinois - November 14, 2001 | 3:30 PM | RI 480 | Wednesday colloquium
Observation of Structure in the Cosmic Ray Spectrum below the GKZ-cutoff Energy by the HiRes Detector Pierre Sokolsky, University of Utah - November 27, 2001 | 3:30 PM | RI 480 | Wednesday colloquium
Dark Halos and Galaxy Formation James Bullock, Ohio State University - November 28, 2001 | 3:30 PM | RI 480 | Wednesday colloquium
Progress in Three-Dimensional Modeling of Type la Supernova Explosions Alexei Khokhlov, Naval Research Laboratory - December 12, 2001 | 4:00 PM | KPTC 106 | Wednesday colloquium
The Dark Energy Problem Edward Witten, Institute for Advanced Study
FRIDAY NOON SEMINARS - October 5, 2001 | 12:00 PM | LASR Conference Room | Friday noon seminar
How CDM explains Milgrom's Law Michael Turner, University of Chicago - October 12, 2001 | 12:00 PM | LASR Conference Room | Friday noon seminar
The Dark Galaxy Problem and the Effects of Substructure on Gravitational Lenses Ben Metcalf, IoA
I argue that the cold dark matter (CDM) model requires that even within a few kpc of the center of a galactic halo a significant fraction (greater than a few percent) of the surface density is contained in substructures with masses > 10^3 solar masses. These structures should be light enough to avoid dynamical friction and dense enough to avoid tidal disruption. I then show using the results of numerical simulations that this substructure will significantly alter the flux ratios of multiply imaged quasars (QSOs) without changing the image positions. The degree to which this occurs will depend on the angular size of the QSO and thus the wavelength of the observations. - October 19, 2001 | 12:00 PM | LASR Conference Room | Friday noon seminar
Are cosmic rays a cause of climate change? Jasper Kirkby, CERN
Recent observations suggest that cosmic rays may play a significant role in the climate. In particular, satellite data have revealed a surprising correlation between cosmic ray intensity and the fraction of the Earth covered by low clouds. Since the cosmic ray intensity is modulated by the solar wind, this could provide an important clue to the long-sought mechanism connecting solar and climate variability. Moreover, if this connection were to be established, it could have significant consequences for our understanding of the solar contributions to the present global warming, since the cosmic ray intensity has fallen during the 20th century due to a more-than-doubling of the strength of the solar wind. In order to the test whether cosmic rays and clouds are causally linked and, if so, to understand the microphysical mechanisms, a novel particle-accelerator experiment known as CLOUD has been proposed. The talk will discuss the scientific case for a connection between cosmic rays and clouds, and describe the proposed CLOUD facility. - November 2, 2001 | 12:00 PM | LASR Conference Room | Friday noon seminar
Towards a Complete Picture of Damped Lyman Alpha Systems Eric Gawiser, UCSD
Damped Lyman alpha Absorption systems (DLAs) contain most of the neutral hydrogen in the high-redshift universe and are the likely progenitors of typical galaxies like the Milky Way. Nonetheless, it is not yet clear whether DLAs are massive galaxies or low-mass protogalaxies, or whether they are connected with the Lyman break galaxies or represent a separate population. I will present results from an observational program designed to clarify the DLA picture. Neither the fraction of the matter density comprised by neutral hydrogen nor the metallicity of the universe as probed by DLAs evolves from z=4 to z=2. Dust extinction does not appear to bias these measurements significantly. The cosmic star formation rate measured in DLAs is comparable to that of Lyman break galaxies and may explain the observed excess of the Near Infrared Background radiation. Finally, I will describe an ongoing effort to determine the mass of DLAs by studying their cross-correlation with Lyman break galaxies. - November 9, 2001 | 12:00 PM | LASR Conference Room | Friday noon seminar
Cosmological Insights from TeV Gamma Rays Scott Wakely, University of Chicago
The present and future generations of TeV gamma-ray detectors can provide interesting probes of a variety of cosmological issues. The technique of ground-based gamma ray astronomy and some of the cosmological questions which it can address will be presented. Recent results from the Whipple 10 m telescope will be discussed, as well as prospects for the new VERITAS 7-telescope array, currently under construction. - November 16, 2001 | 12:00 PM | LASR Conference Room | Friday noon seminar
Inflation, Braneworlds and Quintessence Greg Huey, Queen Mary
Inflationary cosmology is developed in the second Randall-Sundrum braneworld scenario, where the accelerated expansion arises through potentials that are too steep to drive inflation in conventional cosmology. A relationship between the scalar and tensor perturbation spectra is derived that is independent of both the inflaton potential and the brane tension. It is found that a single field with an inverse power law potential can act as both the inflaton and the quintessence field for suitable values of the brane tension. - November 30, 2001 | 12:00 PM | LASR Conference Room | Friday noon seminar
k-Essence and late time cosmic acceleration Christian Armendariz-Picon, University of Chicago
Several different experiments seem to imply that the universe is presently undergoing a stage of accelerated expansion. If this expansion is due to the late dominance of a cosmological constant or a slowly evolving scalar field, it is hard to understand why cosmic acceleration has started just recently rather than at a much earlier epoch. k-Essence attempts to address this puzzle by linking late time cosmic acceleration to the moment of matter-radiation equipartition. k-Essence relies on a very general family of scalar fields with non-linear kinetic terms. We discuss how the requirement of a consistent cosmology constrains these kinetic terms and how due to dynamical reasons k-essence happens to drive cosmic acceleration today. We also point out how, in principle, it is possible to experimentally distinguish k-essence from other dark energy forms such as a cosmological constant or quintessence. - December 7, 2001 | 12:00 PM | LASR Conference Room | Friday noon seminar
Large scale structure and voids Ravi Sheth, FNAL
Whereas most of the luminous mass in the universe is in dense clusters of galaxies, most of the volume is in regions which are much less dense. I'll discuss analytic models for the number and spatial distribution of massive clusters, and show how the models can be extended to describe voids.
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