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HEP: Non-linear growth of large-scale structure with massive neutrinos

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Yacine Ali-Haimoud, Institute for Advanced Study
15 October 2014 from 2:30 PM to 3:30 PM
339 Davey Laboratory
Contact Name
Miguel Mostafa
Contact Phone
(814) 865-4306
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Massive neutrinos make up a fraction of the dark matter, but due to their large thermal velocities, cluster significantly less than cold dark matter (CDM) on scales smaller than their free-streaming scale. An accurate modeling of their effect during the non-linear regime of structure formation is required in order to properly analyze current and upcoming high-precision large-scale structure data, and constrain the neutrino mass. The standard approach consists in introducing neutrinos as particles in N-body simulations. This requires more memory and is subject to shot noise due to the weak clustering of neutrinos. I will show that the evolution of neutrinos in the non-linear CDM background can be solved for analytically, without any additional memory cost compared to the pure CDM case. For neutrino masses below the current limits, the total matter power spectrum obtained with our CDM-neutrino code is extremely accurate on all relevant scales. The clustering of neutrinos itself is underestimated at late times, and I will discuss a hybrid approach being implemented which will solve this remaining issue.