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Astron. Astrophys. 333, 779-789 (1998)

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Non-linear dynamics and mass function of cosmic structures

II. Numerical results

Edouard Audit 1, Romain Teyssier 2 and Jean-Michel Alimi 1

1 Laboratoire d'Astrophysique Extragalactique et de Cosmologie, Observatoire de Paris-Meudon, F-92195 Meudon Cedex, France
2 CEA, DSM/DAPNIA/Service d'Astrophysique CE-SACLAY, F-91191 Gif-sur-Yvette, France

Received 3 November 1997 / Accepted 13 February 1998


We compare the mass functions obtained analytically, in the framework of an extended Press & Schechter (PS) formalism, in a previous paper to the numerical mass functions obtained in N - body simulations, using different algorithms to define objects in the density field. After discussing the properties of the algorithms, we show that the mass function obtained using the friend - of - friend algorithm reproduces best the scaling behaviors predicted in the extended PS formalism. Following this statistical analysis, we show that it is possible in the framework of our extended PS formalism to reproduce the mass function but also, and for the first time, the initial statistical properties of structures and their collapse time. This allow to present a "coherent" picture of structure formation which can account for the initial, final and dynamical properties of structures.

Key words: cosmology: theory – large-scale structure of Universe – gravitation – methods: numerical

© European Southern Observatory (ESO) 1998

Online publication: April 28, 1998