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Cosmological hydrodynamical simulations of clustering dark energy with Nefertiti

Linda Blot, Théo Gayoux, Fabian Schmidt, Pier Stefano Corasaniti, Bastien de Ligondes

Abstract

We present the first cosmological simulations that consistently include nonlinear clustering dark energy evolved as a fluid with the numerical hydrodynamics code Nefertiti. Dark energy perturbations become fully nonlinear on small scales, developing significant density fluctuations without exhibiting the catastrophic instabilities previously reported. We show results for the density distribution, power spectrum, and halo profiles of dark energy. Clustering dark energy contributes to the total density perturbation at the $\sim 10\%$ level inside and around massive halos in our simulations with constant $w=-0.9$, a significant potential signal for lensing and dynamical probes. These simulations pave the way to robust constraints on the speed of sound of dark energy perturbations from large-scale structure data.

Cosmological hydrodynamical simulations of clustering dark energy with Nefertiti

Abstract

We present the first cosmological simulations that consistently include nonlinear clustering dark energy evolved as a fluid with the numerical hydrodynamics code Nefertiti. Dark energy perturbations become fully nonlinear on small scales, developing significant density fluctuations without exhibiting the catastrophic instabilities previously reported. We show results for the density distribution, power spectrum, and halo profiles of dark energy. Clustering dark energy contributes to the total density perturbation at the level inside and around massive halos in our simulations with constant , a significant potential signal for lensing and dynamical probes. These simulations pave the way to robust constraints on the speed of sound of dark energy perturbations from large-scale structure data.
Paper Structure (2 sections, 25 equations, 5 figures)

This paper contains 2 sections, 25 equations, 5 figures.

Table of Contents

  1. Equations
  2. Integration of the source terms

Figures (5)

  • Figure 1: Top panel: Non-linear dark energy power spectrum between redshift 4 and 0 from Nefertiti (continuous lines), and linear prediction from CAMB (dashed lines). Bottom panel: relative difference between the nonlinear and linear power spectra.
  • Figure 2: Top panel: Non-linear matter power spectrum between redshift 4 and 0 from Nefertiti (continuous lines) and linear predictoin from CAMB (dashed lines). Bottom panel: relative difference between the nonlinear and linear power spectra.
  • Figure 3: Ratio of the matter power spectrum in clustering dark energy (clDECDM) and $w$CDM cosmologies from Nefertiti (continuous lines) and CAMB (dashed lines).
  • Figure 4: Mean density perturbation profiles for dark energy (in blue) and matter (in orange) as a function of radius, normalised to the virial radius, for the $N_h = 24$ most massive halos in the clDECDM simulation at $z=0$. Error bars are given by the standard deviation across the halo sample. The dash-dotted horizontal blue line shows the density threshold at which $\delta_{\rm de} = 1$. Above this value, dark energy is fully non-linear.
  • Figure 5: Redshift evolution of DE (upper row) and matter (lower row) overdensity slices predicted by Nefertiti. The redshift corresponding to each snapshot is shown in the top-left corner of each panel of the upper row.