# Mécanique statistique des systèmes autogravitants

Abstract : The self-gravitating systems are formed by particles interacting through gravity. They describe structure formation in the universe. As a consequence of the long range interaction of gravity, they are inhomogeneous even at thermal equilibrium. We study the self-gravitating systems with several kinds of particles and the self-gravitating systems in the presence of the cosmological constant $\Lambda$. We formulate the statistical mechanics and the mean field approach describing the gaseous phase. We explicitely compute the density of particles and thermodynamic quantities. The presence of $\Lambda$ extends the domain of stability of the gaseous phase. Monte Carlo simulations show that the mean field describes the gaseous phase with an excellent accuracy. Scalling law of the self-gravitating systems with several kinds of particles is found. At the critical point the fractal dimension is independant of their composition and is $1.6...$~.
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Cited literature [20 references]

https://tel.archives-ouvertes.fr/tel-00009667
Contributor : Julien Siebert <>
Submitted on : Monday, July 4, 2005 - 6:12:59 PM
Last modification on : Wednesday, December 9, 2020 - 3:10:41 PM
Long-term archiving on: : Tuesday, September 7, 2010 - 5:14:18 PM

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• HAL Id : tel-00009667, version 1

### Citation

Julien Siebert. Mécanique statistique des systèmes autogravitants. Astrophysique [astro-ph]. Université Pierre et Marie Curie - Paris VI, 2005. Français. ⟨tel-00009667⟩

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