Orateur
Description
The Dark Energy Spectroscopic Instrument (DESI) published its DR2 Baryon Acoustic Oscillation (BAO) measurement in March 2025, based on a spectroscopic sample of over 14 million galaxies and quasars. After an overview of the DESI survey itself, I will present the DR2 BAO measurement and its cosmological implications, with a particular focus on neutrino mass constraints and on the nature of dark energy.
Indeed, the results are well described by the ΛCDM framework, and combined to cosmic microwave background measurements (e.g., from Planck), they yield the most stringent cosmological neutrino mass contraint to date. However, a mild tension arises when combining with CMB measurements, which can be alleviated by the introduction of dynamical dark energy. This may be a hint of departure from our standard ΛCDM cosmological model.
