Probing Interacting Dark Sectors with upcoming Post-Reionization and Galaxy Surveys

TL;DR

This paper forecasts how upcoming galaxy and 21-cm surveys like SKA-mid and Euclid can significantly tighten constraints on interactions between dark energy and dark matter, surpassing current observational bounds.

Contribution

It introduces a forecast analysis demonstrating the potential of future surveys to improve constraints on dark sector interactions using mock datasets and MCMC methods.

Findings

SKA-mid and Euclid can significantly improve dark sector interaction constraints.

SKA2 provides the tightest constraints, especially on interaction strength.

Euclid achieves constraints comparable to SKA1.

Abstract

We investigate the constraining power of future post-reionization and galaxy surveys on possible interactions between dynamical dark energy and dark matter. The analysis focuses on the interaction strength and the dark energy equation of state parameters, in addition to the six standard cosmological parameters. Using fiducial values obtained from the current observational bounds (Planck 2018 + DESI DR2 + Pantheon+), mock datasets for upcoming 21-cm intensity mapping, galaxy clustering and cosmic shear observations from the SKA-mid, and for the upcoming large-scale survey from the Euclid mission, were generated. Subsequently, Markov chain Monte Carlo analyses combining current cosmological data with these mock datasets were performed to forecast parameter constraints. The results indicate that both SKA-mid and Euclid observations can significantly improve constraints on interacting dark sector parameters. In particular, the interaction strength and dark energy equation of state parameters can be constrained considerably tighter than current combined constraints from Planck 2018, DESI DR2 and Pantheon+. Comparing different probe combinations and survey configurations, it is found that SKA2 provides the tightest projected constraints, particularly on the interaction strength, while Euclid achieves a precision broadly comparable to that of SKA1. The results highlight the potential of these upcoming surveys to probe interactions within the dark sector.