Silvia GALLIPhysique

Consolidator Grant

Institut d'astrophysique de Paris (IAP, CNRS/Sorbonne Université)

The New era of EUropean CMB Cosmology with the South Pole Telescope NEUCosmoS

The goal of NEUCosmoS is to unravel some of the most severe inconsistencies that are currently threatening the so-far very successful standard model of cosmology (ΛCDM). The most critical one is the steadily growing 5σ difference in the measurement of the expansion rate of the universe today, the Hubble constant, from early-time probes (CMB) versus late-time ones (supernovae Ia). Additional discrepancies persist in the amplitude of matter perturbations, σ8, and in other fundamental parameters, such as the curvature of the universe. These anomalies, if confirmed, will have revolutionary implications for physics. In this context, NEUCosmoS will provide new, ground-breaking insight through the development of a robust analysis pipeline, allowing us to extract the most precise cosmological information from one of the forefront, post-Planck CMB experiments: the South Pole Telescope 3rd-Generation (SPT-3G). SPT-3G will measure the CMB small-scale polarization with unprecedented accuracy over the next 5 years, opening an entirely new window in CMB cosmology, with potentially original discoveries on its own. However, this statistical power will be useless without an analysis able to guarantee robustness against systematic effects, which the PI of this proposal is an expert on. For this reason, she was invited by the SPT collaboration to lead this effort, opening a unique opportunity of European access to the SPT-3G data. NEUCosmoS will provide a framework to transform the existing SPT-3G pipeline into one with quality comparable to satellite missions, building upon the PI’s Planck experience and tools, adapting them to the new challenge. The NEUCosmoS team will drive the interpretation of current and future hints of new physics in a reliable way, with statistical power comparable to the Planck satellite, and in combination with it, almost doubling the constraining capability. This will pave the way to a future contribution by Europe to the next-generation of CMB experiments.