Résumé :
Galaxy clusters are important cosmological probes as their spatial distribution, abundance and their correlations with other observables trace the matter distribution and the growth rate of the universe. These observables depend on the position and mass estimates of the clusters. The latter is the largest source of uncertainty on cosmological constraints since the cluster masses are not directly observed. These are estimated from different observables such as the X-ray flux, richness (both through the so-called mass-observable relations) and the weak lensing signal. In this work we discuss a methodology to estimate the masses of individual clusters from the weak lensing signal (reduced shear) of galaxies. In particular we apply the approach previously used by the 'Weighing the Giants' team, based on the use of the full photometric redshift (photo-z) distributions of these lensed galaxies, in order to better calibrate the mass-observable relations. The full photo-z method is implemented in the Numerical Cosmology (NumCosmo) library. We are also extending this approach including astrophysical/cosmological effects, such as miscentering and the 2-halo term, as well as generalizing it to use any matter density profile. This work has been developed with the Cluster WG of the DESC collaboration, being part of the CLMassMod project.
Début du webinaire : 10h précises, fin 11h au plus tard, ici http://cern.ch/go/7Zlm
