Extended Dark Energy analysis using DESI DR2 BAO measurements

Understand

We conduct an extended analysis of dark energy constraints, in support of the findings of the DESI DR2 cosmology key paper, including DESI data, Planck CMB observations, and three different supernova compilations.

• Using a broad range of parametric and non-parametric methods, we explore the dark energy phenomenology and find consistent trends across all approaches, in good agreement with the $w_0w_a$CDM key paper results.
• Even with the additional flexibility introduced by non-parametric approaches, such as binning and Gaussian Processes, we find that extending $\Lambda$CDM to include a two-parameter $w(z)$ is sufficient to capture the trends present in the data.
• Finally, we examine three dark energy classes with distinct dynamics, including quintessence scenarios satisfying $w \geq -1$, to explore what underlying physics can explain such deviations.