Events at Physics |
Events on Tuesday, March 28th, 2017
- Chaos & Complex Systems Seminar
- 2016 Polling in Nation and State: A scorecard
- Time: 12:05 pm - 1:00 pm
- Place: 4274 Chamberlin (refreshments will be served)
- Speaker: Charles Franklin, Law and Public Policy and Director of the Marquette University Law School Poll
- Abstract: How did the pre-election polls of 2016, at both national and state levels, perform? What did we learn about the dynamics of the campaign and the issues affecting public polling? How accurate were the polls and were some methods better than others?
- Host: Clint Sprott
- Theory Seminar (High Energy/Cosmology)
- Cosmology from Non-Linear Weak Lensing
- Time: 3:30 pm
- Place: 5280 Chamberlin Hall
- Speaker: Zoltan Haiman, Columbia Univ
- Abstract: Several large astronomical surveys have either been proposed or are underway to measure weak lensing distortions of up to a billion galaxies. This will allow accurate measurement of the lensing shear field in the small-scale, non-linear regime, where non-Gaussian features can contain significant cosmological information. I will report on results from a large suite of ray-tracing N-body simulations in different cosmologies, and discuss constraints from the number counts of lensing peaks (i.e. from the number of maxima as a function of their height), and from other statistics probing the non-linear<br>
regime. These statistics can tighten cosmological constraints by a factor of two, compared to using two-point statistics alone. A recent application of this approach to the CFHTLenS survey has confirmed this for the parameters (Omega_m,sigma_8). I will comment on the theoretical and simulation challenges for larger lensing surveys in<br>
the future. - Host: Joshua Berger