Year: 2026
Type: article
Abstract: Analyses by the Dark Energy Spectroscopic Instrument (DESI) collaboration suggest a significant deviation from the ΛCDM model when their baryon acoustic oscillation (BAO) measurements are combined with Planck cosmic microwave background (CMB) data and various Type Ia supernova (SNIa) samples. In this work, we systematically investigate the origin of the deviations from the ΛCDM reported in recent cosmological analyses by combining different CMB datasets, BAO measurements, and DESY5 SNIa samples within the w 0 w a CDM framework. We find that the DESY5 SNIa sample, particularly its low-redshift component (DES-lowz), the Planck CMB data, the lensing measurements of Planck and ACT-DR6, and the DESI-DR2 BAO measurements contribute most significantly to the observed tensions. In contrast, combinations involving DES-SN, WMAP, SPT, and ACT-DR6 remain consistent with ΛCDM within ∼ 1 σ . Our results highlight the critical impact of SNIa systematics, CMB data, and the choice of BAO dataset on constraints of dynamical dark energy models. These findings underscore the importance of improved calibration, homogeneity, and cross-validation of observational datasets to robustly assess potential deviations from the standard cosmological model.
Authors: Da-Chun Qiang, Jing-Yi Jia, Hao Wei
Institutions: Henan Academy of Sciences, Beijing Institute of Technology
Language: English
Subfield: Astronomy and Astrophysics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: green
Awards: G6375264228, G6628817643
OpenAlex ID: W4414711604