Model independent constraints on transition redshift

TL;DR

This study constrains the cosmic transition redshift using model-independent methods with supernovae and H(z) data, providing tighter bounds and estimates for when cosmic acceleration began.

Contribution

It introduces a model-independent framework to estimate the transition redshift using parametrizations of distance, Hubble parameter, and deceleration parameter.

Findings

Transition redshift estimates around 0.81, 0.87, and 0.97 with respective uncertainties.

Supernovae and H(z) data complement each other, tightening constraints.

Provides cosmological-model independent bounds on the onset of cosmic acceleration.

Abstract

This paper aims to put constraints on the transition redshift $z_t$, which determines the onset of cosmic acceleration, in cosmological-model independent frameworks. In order to perform our analyses, we consider a flat universe and {assume} a parametrization for the comoving distance $D_C(z)$ up to third degree on $z$, a second degree parametrization for the Hubble parameter $H(z)$ and a linear parametrization for the deceleration parameter $q(z)$. For each case, we show that {type Ia supernovae} and $H(z)$ data complement each other on the parameter {space} and tighter constrains for the transition redshift are obtained. By {combining} the type Ia supernovae observations and Hubble parameter measurements it is possible to constrain the values of $z_t$, for each approach, as $0.806\pm 0.094$, $0.870\pm 0.063$ and $0.973\pm 0.058$ at 1$\sigma$ c.l., respectively. Then, such approaches provide cosmological-model independent estimates for this parameter.