Hydrodynamical simulations of galaxy clusters in dark energy cosmologies: I. general properties

TL;DR

This study uses hydrodynamical simulations to explore how various dark energy models influence galaxy cluster formation, baryon content, and observable proxies, revealing that X-ray temperature and gas mass functions effectively distinguish different cosmologies.

Contribution

It provides a comparative analysis of galaxy cluster properties across multiple dark energy models, incorporating baryonic physics and star formation, which was not extensively done before.

Findings

Dynamical dark energy models alter star formation rates and cluster formation histories.

Baryon physics remains largely unaffected by dark energy variations.

X-ray temperature and gas mass functions are effective in differentiating dark energy models.

Abstract

We investigate the influence of dark energy on structure formation, within five different cosmological models, namely a concordance $\Lambda$CDM model, two models with dynamical dark energy, viewed as a quintessence scalar field (using a RP and a SUGRA potential form) and two extended quintessence models (EQp and EQn) where the quintessence scalar field interacts non-minimally with gravity (scalar-tensor theories). We adopted for all models the normalization of the matter power spectrum $\sigma_{8}$ to match the CMB data. In the models with dynamical dark energy and quintessence, we describe the equation of state with $w_0\approx-0.9$, still within the range allowed by observations. For each model, we have performed hydrodynamical simulations in a cosmological box of $(300 \ {\rm{Mpc}} \ h^{-1})^{3}$ including baryons and allowing for cooling and star formation. The contemporary presence of evolving dark energy and baryon physics allows us to investigate the interplay between the different background cosmology and the evolution of the luminous matter. Since cluster baryon fraction can be used to constrain other cosmological parameters such as $\Omega_{m}$, we also analyse how dark energy influences the baryon content of galaxy clusters. We find that, in models with dynamical dark energy, the evolving cosmological background leads to different star formation rates and different formation histories of galaxy clusters, but the baryon physics is not affected in a relevant way. We investigate several proxies of the cluster mass function based on X-ray observables like temperature, luminosity, $M_{gas}$, and $Y_{gas}$. We conclude that the X-ray temperature and $M_{gas}$ functions are better diagnostic to disentangle the growth of structures among different dark energy models. [Abridged]