N-point correlations in CDM and ΩCDM simulations

I. Szapudi, Thomas Quinn, Joachim Stadel, George Lake

Research output: Contribution to journalArticle

22 Citations (Scopus)

Abstract

Higher order statistics are investigated in Ω cold dark matter (CDM) universes by analyzing 500 h-1 Mpc high-resolution tree N-body simulations with both Ω = 1 and Ω <1. The amplitudes of the N-point correlation functions are calculated from moments of counts-in-cells determined by a pair of new algorithms especially developed for large simulations. This approach enables massive oversampling with ≃ 109-1014 cells for accurate determination of factorial moments from up to 47 million particles in the scale range of 8 h-1 kpc-125 h-1 Mpc. Thorough investigation shows that there are three scale ranges in the simulations: ≥ 8 h-1 Mpc, a weakly nonlinear regime where perturbation theory applies with utmost precision; 1-8 h-1 Mpc, the nonlinear plateau; and finally ≤1 h-1 Mpc, a regime where dynamical discreteness effects dominate the higher order statistics. In the physically relevant range of 1-125 h-1 Mpc the results (1) confirm the validity of perturbation theory in the weakly nonlinear regime; (2) establish the existence of a plateau in the highly nonlinear regime similar to the one observed in scale-free simulations; (3) show extended perturbation theory to be an excellent approximation for the nonlinear regime; (4) find the time-dependence of the SN's to be negligible in both regimes; (5) in comparison with similar measurements in the Edinburgh-Durham Southern Galaxy Catalog survey, strongly support Ω <1 with no biasing; and (6) show that the formulae of Szapudi and Colombi provide a good approximation for errors on higher order statistics measured in N-body simulations.

Original languageEnglish
Pages (from-to)54-63
Number of pages10
JournalAstrophysical Journal
Volume517
Issue number1 PART 1
Publication statusPublished - May 20 1999

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dark matter
perturbation theory
simulation
perturbation
statistics
plateaus
plateau
moments
cells
approximation
time dependence
catalogs
universe
cold
galaxies
high resolution

Keywords

  • Cosmology: theory
  • Galaxies: clusters: general
  • Large-scale structure of universe
  • Methods: data analysis
  • Methods: laboratory

ASJC Scopus subject areas

  • Nuclear and High Energy Physics
  • Space and Planetary Science

Cite this

Szapudi, I., Quinn, T., Stadel, J., & Lake, G. (1999). N-point correlations in CDM and ΩCDM simulations. Astrophysical Journal, 517(1 PART 1), 54-63.

N-point correlations in CDM and ΩCDM simulations. / Szapudi, I.; Quinn, Thomas; Stadel, Joachim; Lake, George.

In: Astrophysical Journal, Vol. 517, No. 1 PART 1, 20.05.1999, p. 54-63.

Research output: Contribution to journalArticle

Szapudi, I, Quinn, T, Stadel, J & Lake, G 1999, 'N-point correlations in CDM and ΩCDM simulations', Astrophysical Journal, vol. 517, no. 1 PART 1, pp. 54-63.
Szapudi I, Quinn T, Stadel J, Lake G. N-point correlations in CDM and ΩCDM simulations. Astrophysical Journal. 1999 May 20;517(1 PART 1):54-63.
Szapudi, I. ; Quinn, Thomas ; Stadel, Joachim ; Lake, George. / N-point correlations in CDM and ΩCDM simulations. In: Astrophysical Journal. 1999 ; Vol. 517, No. 1 PART 1. pp. 54-63.
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