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### Event Number 4370

**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**Presentation:**Haiman-slides.pdf- Add this event to your calendar