Seminário de Arthur Loureiro (UCL) nesta sexta-feira às 10h

Na próxima sexta-feira, dia 26/11 às 10 h, teremos o Seminário de Arthur Loureiro (UCL), intitulado: "Harmonic analysis of KiDS-1000 Cosmic Shear and tensions with the Cosmic Microwave Background".

Link: https://us02web.zoom.us/j/87309346620?pwd=YzdCLzJCRVhkb0tuSGJiV1dHSk9pUT09

Todos são bem vindos!

Harmonic analysis of KiDS-1000 Cosmic Shear and tensions with the Cosmic Microwave Background

Arthur Loureiro (UCL)

Abstract: The KiDS-1000 cosmic shear catalogue is a state-of-the-art nine-band weak lensing catalogue, measuring over 21 million galaxy shapes with redshifts ranging from 0.1 to 1.2 in photometric redshift. Using a new pseudo angular power spectrum estimator (PCL) under development for the ESA Euclid mission, we performed a tomographic weak lensing analysis of the KiDS-1000 catalogue in harmonic space. A series of tests are carried out to check for systematic contaminations from a variety of observational sources, including stellar number density, variations in survey depth, point spread function properties as well as B-Mode leakage and contamination. We then perform a Bayesian analysis of the PCLs estimates by forward-modelling effects of the mask and assuming a flat LCDM cosmology, probing the structure growth parameter, S8, with per cent-level accuracy. Furthermore, we combine the cosmic shear data from KiDS-1000 with baryon acoustic oscillations and redshift space distortion data from recent SDSS measurements of LRGs, as well as the Ly-alpha forest and its cross-correlations with quasars. This helps us to break the known degeneracies in the weak lensing parameter space, leading to even tighter constraints for S8. Even though the results are in very good agreement with previous KiDS-1000 analysis, as well as other weak lensing experiments, we also find tensions with early-Universe constraints from cosmic microwave background experiments.