In this short contribution, we explore the prior dependence of the recent DESI results, according to which a Bayesian comparison of ΛCDM with w0waCDM cosmologies favors dynamical dark energy. It is a simple exercise to show that extending the prior lower bound of the dark energy parameters tilts the preference in favor of ΛCDM. Adopting the PantheonPlus supernovae catalog, for instance, a shift of the lower bound for w0,wa from −3 to beyond −4.6 and −5, respectively, is sufficient to favor ΛCDM. This calls for caution when interpreting DESI results in the Bayesian context.
@article{arxiv.2407.06586,
title = {The prior dependence of the DESI results},
author = {Vrund Patel and Amlan Chakraborty and Luca Amendola},
journal= {arXiv preprint arXiv:2407.06586},
year = {2024}
}