Implications of DES 5YR SNe Dataset for $Λ$CDM
Eoin Ó Colgáin, Saeed Pourojaghi, Mohammad Mehdi Sheikh-Jabbari · arXiv (Cornell University) · 2024
Dark Energy Survey five-year supernovae data (DES 5YR SNe) in conjunction with Planck CMB and Dark Energy Spectroscopic Instrument (DESI) BAO data has detected a strong dynamical dark energy (DE) deviation from the $Λ$CDM model.Here we shift the focus of DES data to the pressureless matter sector in the $Λ$CDM model by studying the matter density parameter $Ω_m$. Employing primarily frequentist profile likelihoods, supported by complementary Bayesian methods, we demonstrate that $Ω_m$ increases with effective redshift in the DES data up to a point that there is a $2.5 σ$ discrepancy with Planck. We relax the traditional $Ω_m \leq 1$ prior to demonstrate negative DE densities $Ω_m > 1$ at the highest effective redshift probed. Nevertheless, the largest discrepancy with Planck occurs for profile likelihoods and posteriors peaked at $Ω_m 3 σ$. Our choice of $Ω_k$ prior leads to an underestimation of the tension with a flat Universe.