Cosmography and cosmic acceleration

TL;DR

This paper assesses the ability of upcoming measurements of the universe's expansion rate to determine cosmic acceleration, highlighting the need for higher accuracy than current surveys provide.

Contribution

It demonstrates that model-independent evidence for cosmic acceleration requires more precise $H(z)$ data than planned surveys can currently achieve.

Findings

Current surveys lack sufficient accuracy to confirm acceleration independently.

Monte Carlo simulations show the limitations of reconstructing dark energy properties.

Higher precision in $H(z)$ measurements is necessary for definitive conclusions.

Abstract

We investigate the prospects for determining the accelerating history of the Universe from upcoming measurements of the expansion rate $H(z)$. In our analyses, we use Monte Carlo simulations based on $w$CDM models to generate samples with different characteristics and calculate the evolution of the deceleration parameter $q(z)$. We show that a cosmographic (and, therefore, model-independent) evidence for cosmic acceleration ($q(z<z_t) < 0$, where $z_t$ is the transition redshift) will only be possible with an accuracy in $H(z)$ data greater than the expected in current planned surveys. A brief discussion about the prospects for reconstructing the dark energy equation of state from the parameters $H(z)$ and $q(z)$ is also included.