Two Dynamical Scenarios for Binned Master Sample Interpretation

TL;DR

This paper compares two late Universe models with dark energy, using supernova data, and finds that the model with dark energy-matter interaction is favored, showing a phantom-like equation of state.

Contribution

It introduces and compares two dynamical dark energy scenarios, highlighting the preference for an interacting dark energy-matter model based on supernova data analysis.

Findings

Data favors the dark energy-matter interaction model

The interaction model suggests a phantom-like equation of state near -1

The effective running Hubble constant decreases as discussed in literature

Abstract

We analyze two different scenarios for the late Universe dynamics, resulting into Hubble parameters deviating from the $\Lambda$CDM, mainly for the presence of an additional free parameter, which is the dark energy parameter. The first model consists of a pure evolutionary dark energy paradigm, as result of its creation by the gravitational field of the expanding Universe. The second model also considers an interaction of the evolutionary dark energy with the matter component, postulated via the conservation of the sum of their ideal energy-momentum tensors. These two models are then compared \textit{via} the diagnostic tool of the effective running Hubble constant, with the binned data of the so-called ``Master sample'' for the Type Ia Supernovae. The comparison procedures, based on a standard MCMC analysis, led to a clear preference of data for the dark energy - matter interaction model, which is associated to a phantom matter equation of state parameter (very close to $-1$) when, being left free by data (it has a flat posterior), it is fixed in order to reproduce the decreasing power-law behavior of the effective running Hubble constant, already discussed in literature.