Exploring novel probes and methods for cosmology

Oct 15, 2018 - 11:00 am to 12:00 pm

Campus, Varian 355

Elena Massara (CCA)

There are still many unknowns that cosmological observations might help unveiling. Among these, the value for the sum of neutrino masses and the force driving the  accelerated expansion of the Universe are some of the most interesting challenges. In this talk I will discuss a fairly new probe, the cosmic voids, and a novel method, an emulator with simulations on the fly, to extract cosmological parameters and understand the nature of neutrinos and dark energy. First, I will discuss how voids can be used as cosmological tools and in particular to extract the neutrino masses. Second, I will present a theoretical framework to describe the matter density profile around voids and the void bias, which allows to understand the void evolution, provides the structure of fitting formulae for data analysis and gives insights on the RSD analysis with voids. Finally, I will talk about the design of the new emulator we are developing. It will generate the galaxy-galaxy power spectrum in redshift space by combining fast quasi-nbody simulations (FastPM), Halo Occupation Distribution (HOD) modeling, and variance cancellation techniques to produce accurate ensemble averaged galaxy power spectra without invoking a large bill of computer hours.