The CoDECS project: a publicly available suite of cosmological N-body simulations for interacting dark energy models

TL;DR

This paper introduces the CoDECS project, which provides an extensive set of cosmological N-body simulations for interacting dark energy models, enabling detailed analysis of their effects on cosmic structure formation.

Contribution

It offers the largest and most diverse suite of simulations for interacting dark energy models, including the bouncing coupled DE scenario, normalized to current observational bounds.

Findings

Impact of DE coupling on nonlinear matter power spectrum analyzed.

Degeneracy between coupling effects and standard cosmological parameters addressed.

Bias between CDM and baryons computed across redshifts and scales.

Abstract

We present the largest set of N-body and hydrodynamical simulations to date for cosmological models featuring a direct interaction between the Dark Energy (DE) scalar field, responsible of the observed cosmic acceleration, and the Cold Dark Matter (CDM) fluid. With respect to previous works, our simulations considerably extend the statistical significance of the simulated volume and cover a wider range of different realizations of the interacting DE scenario, including the recently proposed bouncing coupled DE model. Furthermore, all the simulations are normalized in order to be consistent with the present bounds on the amplitude of density perturbations at last scattering, thereby providing the first realistic determination of the effects of a DE coupling for cosmological growth histories fully compatible with the latest Cosmic Microwave Background data. As a first basic analysis, we have studied the impact of the coupling on the nonlinear matter power spectrum and on the bias between the CDM and baryon distributions, as a function of redshift and scale. For the former, we have addressed the issue of the degeneracy between the effects of the coupling and other standard cosmological parameters, as e.g sigma_8, showing how the redshift evolution of the linear amplitude or the scale dependence of the nonlinear power spectrum might provide a way to break the degeneracy. For the latter, instead, we have computed the redshift and scale dependence of the bias in all our different models showing how a growing coupling or a bouncing coupled DE scenario provide much stronger effects with respect to constant coupling models. We refer to this vast numerical initiative as the COupled Dark Energy Cosmological Simulations project, or CoDECS, and we hereby release all the CoDECS outputs for public use through a dedicated web database, providing information on how to access and interpret the data.