An analytic model for interacting dark energy and its observational constraints

TL;DR

This paper presents an analytic model for interacting dark energy, deriving exact solutions and constraining them with supernova data to explore their cosmological implications and parameter space.

Contribution

It introduces exact analytic solutions for interacting dark energy models with both constant and variable equations of state, and constrains these models using observational supernova data.

Findings

Model asymptotically approaches ΛCDM for small coupling

Model can enter phantom domain with larger coupling

Best-fit parameters are consistent within confidence intervals

Abstract

The paper deals with a theoretical model for interacting dark energy. The interaction between the cold dark matter (dust) and the dark energy has been assumed to be non-gravitational in nature. Exact analytic cosmological solutions are obtained both for constant and variable equation of state for dark energy. It is found that, for very small value of the coupling parameter (in the interaction term), the model asymptotically extends up to $\Lambda$CDM, while the model can enter into the phantom domain asymptotically, if the coupling parameter is not so small. Both the solutions are then analyzed with 194 Supernovae Type Ia data. The best fit parameters are shown with 1$\sigma$ and 2$\sigma$ confidence intervals. Finally, we have discussed the cosmographic parameters for both the cases.