Clustering of galaxy clusters in CDM universes

Collaboration
May, 2000
9 pages
Published in:
  • Mon.Not.Roy.Astron.Soc. 319 (2000) 209
e-Print:
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20002006201220182024051015
Abstract: (arXiv)
We use very large cosmological N--body simulations to obtain accurate predictions for the two-point correlations and power spectra of mass-limited samples of galaxy clusters. We consider two currently popular cold dark matter (CDM) cosmogonies, a critical density model (τ\tauCDM) and a flat low density model with a cosmological constant (Λ\LambdaCDM). Our simulations each use 10910^9 particles to follow the mass distribution within cubes of side 2h12h^{-1}Gpc (τ\tauCDM) and 3h13h^{-1}Gpc (Λ\LambdaCDM) with a force resolution better than 10410^{-4} of the cube side. We investigate how the predicted cluster correlations increase for samples of increasing mass and decreasing abundance. Very similar behaviour is found in the two cases. The correlation length increases from r0=12r_0=12 -- 13h1h^{-1}Mpc for samples with mean separation dc=30h1d_{\rm c}=30h^{-1}Mpc to r0=22r_0=22-- 27h1h^{-1}Mpc for samples with dc=100h1d_{\rm c}=100h^{-1}Mpc. The lower value here corresponds to τ\tauCDM and the upper to Λ\LambdaCDM. The power spectra of these cluster samples are accurately parallel to those of the mass over more than a decade in scale. Both correlation lengths and power spectrum biases can be predicted to better than 10% using the simple model of Sheth, Mo & Tormen (2000). This prediction requires only the linear mass power spectrum and has no adjustable parameters. We compare our predictions with published results for the APM cluster sample. The observed variation of correlation length with richness agrees well with the models, particularly for Λ\LambdaCDM. The observed power spectrum (for a cluster sample of mean separation dc=31h1d_{\rm c}=31h^{-1}Mpc) lies significantly above the predictions of both models.
Note:
  • 9 pages, 5 figures. Accepted for publication in MNRAS. Minor changes Journal-ref: 2000, MNRAS, 319, 209-214
  • COSMOLOGY THEORY
  • DARK MATTER
  • GRAVITATION