Exploring the effects of a double reconstruction on the growth rate of cosmic structure, using current observational data

TL;DR

This paper investigates how a double reconstruction of dark energy and dark matter interactions affects cosmic structure growth, using observational data to distinguish coupled from uncoupled models within General Relativity.

Contribution

It introduces a double reconstruction approach for dark energy and dark matter interactions and analyzes their effects on key cosmological parameters using current observational data.

Findings

Coupled models alter growth rate and Hubble friction compared to uncoupled models.

Observational data constrains the parameters of coupled dark energy scenarios.

Differences in growth index and effective gravitational constants can distinguish models.

Abstract

Based on General Relativity (GR) we consider two different cosmological scenarios in where reconstruct the energy exchange (Q) between cold dark matter (DM) fluid and dark energy (DE) fluid, which is modelled with a DE varying equation of state (EoS) parameter {\omega}. We here investigate the main cosmological effects on the growth rate of matter density perturbations (f{\sigma}8), on the effective Hubble friction term (Heff ), on the effective Newton constant (Geff ) and on the growth index of the linear matter fluctuations ({\gamma}). Our study demonstrates that in the coupled models the evolution of these quantities are modified with respect to the predictions in the uncoupled models, and therefore could be used to distinguish among coupled DE scenarios. Finally, we also perform a combined statistical analysis using current observational data (geometric and dynamical probes) to put more stringent constraints on the parameters space of the cosmic scenarios studied.