Orateur
Description
Early observations from the James Webb Space Telescope (JWST) have revealed an overabundance of massive high-redshift galaxies, raising the question of whether this points to new physics beyond ΛCDM, or an enhanced formation efficiency of massive stars. In this talk, I will present a Bayesian analysis of the most massive galaxies identified in recent JWST photometric and spectroscopic surveys, jointly constraining cosmological parameters and the baryon-to-star conversion efficiency. I will discuss the impact of extensions to the standard ΛCDM model, allowing the dark energy equation of state and spatial curvature to vary. Our results show no evidence for deviations from ΛCDM and suggest that the origin of the “JWST tension” is more likely related to astrophysical processes governing galaxy formation than to modifications of the cosmological model.