Emergent Dark Energy, neutrinos and cosmological tensions

TL;DR

This paper investigates the impact of massive neutrinos and extra relativistic species on the Phenomenologically Emergent Dark Energy model, showing it can alleviate cosmological tensions and hinting at non-zero neutrino mass.

Contribution

It provides updated bounds on neutrino mass and relativistic species within the emergent dark energy framework, demonstrating its robustness against cosmological tensions.

Findings

Neutrino mass estimated at ~0.21 eV with >2σ significance.

Hubble tension is significantly reduced within this model.

The model remains consistent with current cosmological observations.

Abstract

The Phenomenologically Emergent Dark Energy model, a dark energy model with the same number of free parameters as the flat $\Lambda$CDM, has been proposed as a working example of a minimal model which can avoid the current cosmological tensions. A straightforward question is whether or not the inclusion of massive neutrinos and extra relativistic species may spoil such an appealing phenomenological alternative. We present the bounds on $M_{\nu}$ and $N_{\rm eff}$ and comment on the long standing $H_0$ and $\sigma_8$ tensions within this cosmological framework with a wealth of cosmological observations. Interestingly, we find, at $95\%$ confidence level, and with the most complete set of cosmological observations, $M_{\nu}\sim 0.21^{+0.15}_{-0.14}$ eV and $N_{\rm eff}= 3.03\pm 0.32$ i.e. an indication for a non-zero neutrino mass with a significance above $2\sigma$. The well known Hubble constant tension is considerably easened, with a significance always below the $2\sigma$ level.