Theory Seminar (High Energy/Cosmology)

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Events on Tuesday, March 28th, 2017

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
Presentation: Haiman-slides.pdf
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