D-class of dark energy against $\Lambda$CDM in Brans-Dicke cosmology

TL;DR

This paper investigates three dynamical interacting dark energy models within Brans-Dicke cosmology, fitting them to observational data and finding that some models, especially D-D C2, outperform DM in data compatibility.

Contribution

It introduces and tests three new interacting dark energy models in Brans-Dicke cosmology, identifying the D-D C2 model as strongly favored by observational data.

Findings

D-D C2 model fits data better than DM.

Some models are ruled out by data, others are favored.

AIC analysis supports D-D C2 as the best fit.

Abstract

Three general models of dynamical interacting dark energy (D-class) are investigated in the context of Brans-Dicke cosmology. All cosmological quantities such as equation of state parameters, deceleration parameters, Hubble function, and the density ratio are calculated as a function of redshift parameter. The most important part of this paper is fitting of models to the observational data (SNIa+BAO$_A$+$Omh^{2}$). We obtain a table of best fit value of parameters and report $\chi_{tot}^2/dof$ and Akaike Information Criterion (AIC) for each model. By these diagnostic tools, we find that some models have no chance against $\Lambda$CDM and some (e.g. $\mathcal{BD-D}C2$ and $\mathcal{BD-D}A^*$) render the best fit quality. Specially, the value of AIC analysis and figures show that the interacting $\mathcal{BD-D}C2$ model fit perfectly with overall data and reveals a strong evidence in favor of this model, against $\Lambda$CDM.