Constraints on the Dark Energy Equation of State in Presence of a Varying Fine Structure Constant

International audienceWe discuss the cosmological constraints on the dark energy equation of state in the presence of primordial variations in the fine structure constant. We find that the constraints from CMB data alone on w and the Hubble constant are much weaker when variations in the fine structure constant are permitted. Vice versa, constraints on the fine structure constant are relaxed by more than 50% when dark energy models different from a cosmological constant are considered