[ital N]-Point Correlations in CDM and [Omega]CDM Simulations
- University of Durham, Department of Physics, South Road, Durham DH1 3LE, England, (United Kingdom)
- Department of Astronomy, University of Washington, Seattle, WA 98195-1580 (United States)
Higher order statistics are investigated in [Omega] cold dark matter (CDM) universes by analyzing 500 [ital h][sup [minus]1] Mpc high-resolution tree [ital N]-body simulations with both [Omega]=1 and [Omega][lt]1. The amplitudes of the [ital 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 [approx equal]10[sup 9] [endash]10[sup 14] cells for accurate determination of factorial moments from up to 47 million particles in the scale range of 8 [ital h][sup [minus]1] kpc[endash]125 [ital h][sup [minus]1] Mpc. Thorough investigation shows that there are three scale ranges in the simulations: [ge]8 [ital h][sup [minus]1] Mpc, a weakly nonlinear regime where perturbation theory applies with utmost precision; 1[endash]8 [ital h][sup [minus]1] Mpc, the nonlinear plateau; and finally [le]1 [ital h][sup [minus]1] Mpc, a regime where dynamical discreteness effects dominate the higher order statistics. In the physically relevant range of 1[endash]125 [ital h][sup [minus]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 S[sub N]'s to be negligible in both regimes; (5) in comparison with similar measurements in the Edinburgh-Durham Southern Galaxy Catalog survey, strongly support [Omega][lt]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 [ital N]-body simulations. [copyright] [ital [copyright] 1999.] [ital The American Astronomical Society]
- OSTI ID:
- 6272803
- Journal Information:
- Astrophysical Journal, Vol. 517:1; ISSN 0004-637X
- Country of Publication:
- United States
- Language:
- English
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GENERAL PHYSICS
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CORRELATION FUNCTIONS
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NONLUMINOUS MATTER
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661300* - Other Aspects of Physical Science- (1992-)