Determination of the Kinematic Parameters from SNe Ia and Cosmic Chronometers

TL;DR

This study tests eight kinematic models of the universe using observational data to independently estimate key parameters like the Hubble constant and deceleration parameter, favoring a model with constant jerk.

Contribution

It introduces a Bayesian comparison of eight kinematic models using cosmic chronometers and supernova data, identifying the most favored model with specific parameter estimates.

Findings

The constant jerk model is slightly favored by the data.

Estimated Hubble constant is approximately 68.8 km/s/Mpc.

The deceleration parameter is around -0.58.

Abstract

In this work, by assuming a spatially flat Universe, we have tested 8 kinematic parametrization models with $H(z)$ data from Cosmic Chronometers and SNe Ia from Pantheon compilation. Our aim is obtain the current values for the Hubble constant ($H_0$), deceleration parameter ($q_0$), jerk ($j_0$) and snap ($s_0$) parameters independently from a dynamical model. By using a Bayesian model comparison, three models are favoured: a model with the deceleration parameter ($q$) linearly dependent on the redshift, $q$ linearly dependent on the scale factor and a model with a constant jerk. The model with constant jerk is slightly favoured by this analysis, furnishing $H_0=68.8^{+3.7}_{-3.6}$ km/s/Mpc, $q_0=-0.58\pm0.13$, $j_0=1.15^{+0.56}_{-0.53}$ and $s_0=-0.25^{+0.40}_{-0.30}$. The other models are compatible with the constant jerk model, except for the snap parameter, where we have found $s_0=4.0^{+3.4}_{-3.0}$ for the model with $q$ linearly dependent on the scale factor. (All uncertainties in the Abstract correspond to 95\% c.l.).