24–26 Jun 2025
Istanbul Technical University
Europe/Istanbul timezone

Implications for cosmological expansion models from the final Dark Energy Survey BAO and SN data

25 Jun 2025, 11:40
25m
Istanbul Technical University

Istanbul Technical University

İTÜ Ayazağa Campus, Rectorate Building, 34469 Maslak-ISTANBUL Phone:+90 212 285 30 30

Speaker

Juan Mena-Fernández (CNRS - LPSC)

Description

The Dark Energy Survey (DES) recently released the final results of its two main probes of the expansion history: Type Ia Supernovae (SN) and Baryonic Acoustic Oscillations (BAO). In this work, we explore the cosmological implications of these data in combination with external Cosmic Microwave Background (CMB), Big Bang Nucleosynthesis (BBN), and age-of-the-Universe information. The BAO measurement, which is 2σ away from {\tt Planck-2018}'s ΛCDM predictions, pushes for low values of Ωm compared to {\tt Planck-2018}, in contrast to SN which prefers a higher value than {\tt Planck-2018}. We identify several tensions among datasets in the ΛCDM model and try to solve them by including curvature or evolving dark energy. For DES BAO and SN in combination with {\tt Planck-2018}, we find a 3.2σ deviation from ΛCDM when assuming w0waCDM. For the combination of all the background cosmological probes considered (including θ from {\tt Planck-2018}), we still find a deviation of 2.8σ in the w0wa plane. This work provides further evidence for non-ΛCDM physics or systematics, which is consistent with recent claims in support of evolving dark energy.

Primary author

Presentation materials