Cosmic slowing down of acceleration for several dark energy parametrizations

TL;DR

This study examines the universe's slowing acceleration across various dark energy models using multiple observational data sets, revealing a low-redshift deceleration transition that is sensitive to data combination and indicating tensions among data sources.

Contribution

It provides a comprehensive analysis of dark energy parametrizations with combined observational data, highlighting the impact of data sets on acceleration features and data tensions.

Findings

Low-redshift deceleration transition appears with supernova data alone.

Transition feature disappears when combining supernovae with high-redshift data.

Evidence of tension among different supernova samples and data sets.

Abstract

We further investigate slowing down of acceleration of the universe scenario for five parametrizations of the equation of state of dark energy using four sets of supernovae data. In a maximal probability analysis we also use the baryon acoustic oscillation and cosmic microwave background observations. We found the low redshift transition of the deceleration parameter appears, independently of the parametrization, using supernovae data alone except for the Union 2.1 sample. This feature disappears once we combine the supernova data with high redshift data. We conclude that the rapid variation of the deceleration parameter is independent of the parametrization. We also found more evidence for a tension among the supernovae samples, as well as for the low and high redshift data.