Decaying dark energy in light of the latest cosmological dataset

TL;DR

This study investigates decaying dark energy models using recent cosmological data, finding that the accelerated expansion aligns with a cosmological constant and highlighting the importance of future observations for further constraints.

Contribution

The paper provides updated constraints on decaying dark energy models using the latest observational datasets and two different parameter estimation methods.

Findings

Results are consistent with a cosmological constant as the driver of acceleration.

Constraints are improved by fixing Hubble constant and matter density to Planck values.

Forthcoming observations are crucial to distinguish or rule out decaying dark energy models.

Abstract

Decaying Dark Energy models modify the background evolution of the most common observables, such as the Hubble function, the luminosity distance and the Cosmic Microwave Background temperature-redshift scaling relation. We use the most recent observationally-determined datasets, including Supernovae Type Ia and Gamma Ray Bursts data, along with $H(z)$ and Cosmic Microwave Background temperature versus $z$ data and the reduced Cosmic Microwave Background parameters, to improve the previous constraints on these models. We perform a Monte Carlo Markov Chain analysis to constrain the parameter space, on the basis of two distinct methods. In view of the first method, the Hubble constant and the matter density are left to vary freely. In this case, our results are compatible with previous analyses associated with decaying Dark Energy models, as well as with the most recent description of the cosmological background. In view of the second method, we set the Hubble constant and the matter density to their best fit values obtained by the {\it Planck} satellite, reducing the parameter space to two dimensions, and improving the existent constraints on the model's parameters. Our results suggest that the accelerated expansion of the Universe is well described by the cosmological constant, and we argue that forthcoming observations will play a determinant role to constrain/rule out decaying Dark Energy.