Revealing the effects of curvature on the cosmological models

TL;DR

This study investigates how curvature affects extended cosmological models with variable neutrino sectors and dark energy parametrizations, revealing that current data favor a closed universe and that assuming flatness can bias dark energy constraints.

Contribution

It demonstrates that a non-flat universe is compatible with current data and highlights the impact of curvature assumptions on dark energy parameter estimates.

Findings

Current data favor a closed universe in many dark energy models.

Forcing flatness biases dark energy equation of state constraints.

Non-flat models are consistent with Planck, BAO, and supernova data.

Abstract

In this paper we consider the effects of adding curvature in extended cosmologies involving a free-to-vary neutrino sector and different parametrizations of Dark Energy (DE). We make use of the Planck 2018 cosmic microwave background temperature and polarization data, Baryon Acoustic Oscillations and Pantheon type Ia Supernovae data. Our main result is that a non-flat Universe cannot be discarded in light of the current astronomical data, because we find an indication for a closed Universe in most of the DE cosmologies explored in this work. On the other hand, forcing the Universe to be flat can significantly bias the constraints on the equation of state of the DE component and its dynamical nature.