Astronomy Colloquia

January 11, 2012 | 15:30, BSLC 001 | Host: Robert Rosner
Why I compute....
Robert Rosner, University of Chicago
Note: Refreshments served at 3:00PM ~ TAAC 71

January 25, 2012 | 15:30, BSLC 001 | Host: Robert Rosner
Looking for Dark Matter here, there and everywhere
Patrick Fox, FNAL
Note: Refreshments served at 3:00 TAAC 71
The hunt for physics beyond the standard model at the LHC is in full swing. We already know of the existence of (at least) one new particle that is not in the standard model, dark matter. The existence of dark matter was first inferred from astrophysical observations and later confirmed by cosmological measurements. There is considerable ongoing effort to see the effects of dark matter, which makes up the majority of the matter in our galaxy, in a more terrestrial setting. I will outline what is, and what is not, known about dark matter, and explain how we may soon learn a lot more, as well as explaining how the conventional search methods can be complemented by searches at the LHC, and elsewhere.

February 1, 2012 | 15:30, BSLC 001 | Host: Robert Rosner
The DARKSIDE of Dark Matter
Luca Grandi, Princeton University
Note: Refreshments served at 3:00PM TAAC 71
The search for Dark Matter represents one of the most intriguing open frontiers in modern cosmology and astroparticle physics. The science case is extremely strong: observations of the cosmic microwave background fluctuation, large-scale galaxy surveys, studies of large scale structure formation and of the dynamics of galaxy clusters, all point to the existence of cold dark matter. Weakly Interacting Massive Particles (WIMPs) are an excellent candidate for cold dark matter. These particles, predicted in many new theories extending beyond the standard model, may collide with ordinary nuclei via ultra-weak interactions, and could be detected by means of special, low-background detectors, capable of selectively identifying nuclear recoils - the likely signature of WIMP interactions.
I will present and discuss the DarkSide Project for direct dark matter detection. The use of depleted argon as a target in a two-phase time projection chamber, coupled with a powerful neutron veto based on the Borexino technology, results in a unique detector, capable of achieving background-free conditions. DarkSide-50 is the first detector in the DarkSide program, featuring an active mass of 50 kg of depleted argon. It is designed to reach a sensitivity to the WIMP interaction cross section of 10^-45 cm^2 and will be deployed at Laboratori Nazionali del Gran Sasso in Italy in 2012.

February 8, 2012 | 15:30, BSLC 001 | Host: Robert Rosner
Constraining Cosmology using the Growth of Structure and the Cosmic Microwave Background
Brad Benson, University of Chicago
Note: Refreshments served at 3:00PM TAAC 71
While dark energy explains the apparent acceleration of the universe, its properties and nature remains a complete mystery. Measurements of the growth of structure are affected by dark energy in a fundamentally different way than distance-redshift based tests, such as from type Ia supernovae and baryon acoustic oscillations. This makes them useful to break cosmological parameter degeneracies, reduce systematic uncertainty, and are an important systematic test of the standard dark energy paradigm. I will present the most recent cosmological constraints from the South Pole Telescope (SPT), and discuss the role of multi-wavelength cluster observations, primarily through Chandra X-ray and optical weak lensing observations, in improving the dark energy constraints for the full SPT cluster survey. I will also discuss the role of these observations in helping to understand the formation and evolution of massive clusters, and their relevance to future cluster surveys, such as the Dark Energy Survey. Finally, I will discuss the next frontier for CMB experiments of using the lensing of the CMB to measure the growth of structure, the technological challenges for the next generation of experiments, and their projected constraints on dark energy, neutrino mass, and the energy scale of Inflation.

February 22, 2012 | 15:30, BSLC 001 | Host: Robert Rosner
TBA
Alex Friedland,
Note: Refreshments served at 3:00PM TAAC 71

March 7, 2012 | 15:30, BSLC 001 | Host: Robert Rosner
TBA
TBA,
Note: Refreshments served at 3:00PM TAAC 71