Constraint on Coupled Dark Energy Models from Observations

TL;DR

This paper investigates how coupled dark energy models affect cosmological observations, especially the ISW effect, and constrains the interaction strength using current data, with prospects for tighter future constraints.

Contribution

It provides the first comprehensive constraint on the interaction strength in coupled dark energy models using observational data, focusing on the exponential interaction form.

Findings

Interaction strength constrained as β<0.085 at 95% confidence

Future measurements could improve constraints by a factor of two

Coupled dark energy models leave observable imprints on the ISW effect

Abstract

The coupled dark energy models, in which the quintessence scalar field nontrivially couples to the cold dark matter, have been proposed to explain the coincidence problem. In this paper we study the perturbations of coupled dark energy models and the effects of this interaction on the current observations. Here, we pay particular attention to its imprint on the late-time Integrated Sachs-Wolfe (ISW) effect. We perform a global analysis of the constraints on this interaction from the current observational data. Considering the typical exponential form as the interaction form, we obtain that the strength of interaction between dark sectors is constrained as $\beta<0.085$ at 95% confidence level. Furthermore, we find that future measurements with smaller error bars could improve the constraint on the strength of coupling by a factor two, when compared to the present constraints.