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Events on Thursday, February 2nd, 2012
- NPAC (Nuclear/Particle/Astro/Cosmo) Forum
- Recent Results from the COUPP Dark Matter Search
- Time: 2:30 pm
- Place: 4274 Chamberlin Hall
- Speaker: Andrew Sonnenschein, Fermilab
- Abstract: Bubble chambers have emerged as promising detectors for Weakly Interacting Massive dark matter Particles (WIMPs). A very high degree of background discrimination can be achieved by tuning the thermodynamic parameters to avoid nucleation by electron recoils, while maintaining low nuclear-recoil thresholds. Nuclear recoils from WIMPs can be discriminated from alpha particle induced events by analysis of the acoustic pulses produced by the expanding bubbles. The COUPP collaboration operated a 4-kg CF3I bubble chamber at SNOLAB in 2010-2011 and is in the process of commissioning a 60-kg chamber. Initial data from SNOLAB demonstrate reduced alpha backgrounds and greatly improved sensitivity to WIMPs.
- Host: Karsten Heeger
- Astronomy Colloquium
- A (Re) Introduction to the Milky Way (AAS Reprise)
- Time: 3:30 pm
- Place: 4421 Sterling Hall
- Speaker: Bob Benjamin, UW Whitewater
- Abstract: If your picture of the Milky Way is that it consists of a bulge, disk, and halo, you might want to attend this talk. I will review the many recent advances in understanding the global structure of our Galaxy, with a principal emphasis on the disk and inner galaxy. Radio parallaxes to maser sources, extinction distances to dark clouds, and large-scale near and mid-infrared mapping of red clump giants now allow us to map out different components (star formation, gas, and old stars) of the Galaxy without the serious issues that plagued earlier efforts. I will review some of the recent discoveries and directions for future work as I did at a plenary session at the American Astronomical Society meeting in Austin this January. After 60 years of effort, I'd say we're about 50% done mapping the Milky Way.
But as a special only-in-Wisconsin add-on, I will also show an interesting (and in retrospect, totally predictable) discovery I made while preparing for this talk, as well as showing some evidence that indicates the resurgence in Galactic structure may yet hit some rocky roads ahead.
- Host: Astronomy Dept