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oai:recercat.cat:2117/4495572026-01-21T12:11:38Zcom_2072_1033col_2072_452950

Extended dark energy analysis using DESI DR2 BAO measurements Lodha, Kushal Calderon, R. Matthewson, W.L. Shafieloo, Arman Ishak, Mustapha Pan, Jiaming Garcia Quintero, C. Huterer, D. Valogiannis, Georgios Pérez Ràfols, Ignasi Universitat Politècnica de Catalunya. Departament de Física Universitat Politècnica de Catalunya. GAA - Grup d'Astronomia i Astrofísica Àrees temàtiques de la UPC::Física::Astronomia i astrofísica Baryon acoustic oscillations Cosmological parameters Dark energy Large scale structure of the Universe We conduct an extended analysis of dark energy constraints, in support of the findings of the Dark Energy Spectroscopic Instrument (DESI) second data release cosmology key paper, including DESI data, Planck cosmic microwave background observations, and three different supernova compilations. Using a broad range of parametric and nonparametric methods, we explore the dark energy phenomenology and find consistent trends across all approaches, in good agreement with the 𝑤0⁢𝑤𝑎⁢CDM (cold dark matter) key paper results. Even with the additional flexibility introduced by nonparametric approaches, such as binning and Gaussian processes, we find that extending Λ⁢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 ≥−1 , to explore what underlying physics can explain such deviations. The current data indicate a clear preference for models that feature a phantom crossing; although alternatives lacking this feature are disfavored, they cannot yet be ruled out. Our analysis confirms that the evidence for dynamical dark energy, particularly at low redshift (𝑧 ≲0.3 ), is robust and stable under different modeling choices. Peer Reviewed Postprint (published version) 2025-10-06 Article Lodha, K. [et al.]. Extended dark energy analysis using DESI DR2 BAO measurements. «Physical review D», 6 Octubre 2025, vol. 112, núm. article 083511. 2470-0010 https://hdl.handle.net/2117/449557 10.1103/w4c6-1r5j eng https://journals.aps.org/prd/abstract/10.1103/w4c6-1r5j http://creativecommons.org/licenses/by/4.0/ Open Access Attribution 4.0 International application/pdf American Physical Society (APS)