Séminaires et colloques

Precision Cosmology with Cosmic Voids - Alice Pisani

Modern surveys allow us to access to high quality measurements, by sampling the galaxy distribution in detail also in the emptier regions, voids. Cosmic voids present themselves as a new tool to constrain cosmology. While the treatment of systematics might be simpler in these empty regions, with the aim of achieving the level of precision cosmology a careful modeling of such effects is necessary. In particular, peculiar velocities affect the way we observe cosmic voids, and thus their effect needs to be understood. Using mock catalogues, I analyze the effect of peculiar velocities on void properties. In this talk, I first describe the algorithm to find voids in galaxy surveys. I then present the results of the analysis of the systematic effects affecting voids and discuss it in the framework of current and future surveys. Additionally, I present a forecast for void abundances with the future Euclid and WFIRST missions and obtain, using the Fisher matrix formalism, a prediction for the constraints that voids will set on cosmological parameters.