New constraints on neutrino physics from cosmology

Abstract We report the most recent constraints on neutrino parameters from cosmology. Combining recent measurement of cosmic microwave background anisotropies, Hubble constant, and galaxy clustering, the effective number of relativistic degrees of freedom is N e f f = 3.98 ± 0.37 at 68% c.l., hinting towards the possible existence of a fourth sterile neutrino. However, this result strongly depends on the Hubble prior obtained from the HST. With a different prior on the Hubble constant, coming from a median statistic analysis, we have N e f f = 3.52 ± 0.39 at 68% c.l.. The total neutrino mass is bounded to be below Σ m ν 0.36 eV at 95% c.l. in the case of the HST prior but relaxed to Σ m ν 0.60 eV at 95% c.l. in the case of the median statistic prior