Model independent cosmographic constraints from DESI 2024

TL;DR

This paper uses recent DESI BAO data to perform model-independent cosmographic analysis, constraining universe kinematic parameters and comparing with standard cosmological models, revealing a significant departure in the jerk parameter and favoring the wCDM model.

Contribution

It provides the first comprehensive model-independent constraints on cosmographic parameters using DESI 2024 data, including the impact on the Hubble tension and model comparisons.

Findings

Significant departure in jerk parameter j_0 at 1-σ level.

Constraints on q_0, s_0 compatible with ΛCDM at 2-σ.

wCDM model favored over ΛCDM and w_0 parametrizations.

Abstract

In this study, we explore model independent constraints on the universe kinematics up to the snap and jerk hierarchical terms. To do so, we consider the latest Baryon Acoustic Oscillation (BAO) release provided by the DESI collaboration, tackling the $r_d$ parameter to span within the range $[144,152]$ Mpc, with fixed step, $\delta r_d=2$ Mpc, aligning with Planck and DESI results. Thus, employing Monte Carlo Markov chain analyses, we place stringent constraints on the cosmographic series, incorporating three combinations of data catalogs: the first BAO with observational Hubble data, the second BAO with type Ia supernovae, and the last including all three data sets. Our results conclusively constrain the cosmographic series, say the deceleration $q_0$, the jerk $j_0$, and the snap $s_0$ parameters, at the $2$--$\sigma$ level, showcasing a significant departure on $j_0$ even at $1$--$\sigma$ confidence level, albeit being compatible with the $\Lambda$CDM paradigm on $q_0$ and $s_0$, at $2$--$\sigma$ level. Analogously, the $h_0$ tension appears alleviated in the second hierarchy, say including snap. Finally, a direct comparison with the $\Lambda$CDM, $w$CDM models and the Chevallier-Polarski-Linder parametrization is reported, definitively favoring the wCDM scenario.