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Abstract |
Recent cosmological measurements are hinting that dark energy may evolve, with its equation of state, wDE, even showing oscillatory patterns. In this work, we employ a model-independent approach to jointly reconstruct wDE and the sum of neutrino masses, & sum;m, adopting the Piecewise Cubic Hermite Interpolating Polynomial (PCHIP) method with seven fixed nodes in which we allow the two parameters to vary. We employ CMB, Baryon Acoustic Oscillations and Supernovae Ia data to constrain the values of wDE and & sum;m at each node. We conduct three different analyses in which we reconstruct wDE: one with fixed & sum;m = 0.06 eV; one in which we allow & sum;m to vary, and one in which we also reconstruct & sum;m using the PCHIP method. We find the dark energy equation of state to be consistent with the cosmological constant scenario, except when including DESI data and allowing for phantom crossing, where we find a 95% CL deviation from wDE = -1 around z similar to 1.2. For neutrino masses, we obtain looser constraints when focusing on phantom dark energy, that show further early and late relaxation when reconstructing the mass via the PCHIP method. |
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