Astron. Astrophys. 349, 343-353 (1999)

Extending the scope of models for large-scale structure formation in the universe

T. Buchert  ^{*  1}, A. Domínguez ² and J. Pérez-Mercader <sup>2

1</sup> Theory Division, CERN, CH-1211 Geneva 23, Switzerland
² Laboratorio de Astrofísica Espacial y Física Fundamental, Apartado 50727, E-28080 Madrid, Spain (dominguez, mercader@laeff.esa.es)

Received 23 November 1998 / Accepted 29 March 1999

Abstract

We propose a phenomenological generalization of the models of large-scale structure formation in the Universe by gravitational instability in two ways: we include pressure forces to model multi-streaming, and noise to model fluctuations due to neglected short-scale physical processes. We show that pressure gives rise to a viscous-like force of the same character as the one introduced in the adhesion model , while noise leads to a roughening of the density field, yielding a scaling behavior of its correlations.

Key words: gravitation hydrodynamics instabilities methods: analytical cosmology: theory cosmology: large-scale structure of Universe

* On leave from: Theoretische Physik, Ludwig-Maximilians-Universität, Theresienstrasse 37, D-80333 München, Germany (buchert@theorie.physik.uni-muenchen.de)

Send offprint requests to: A. Domínguez

This article contains no SIMBAD objects.

Contents

• 1. Introduction
• 2. Basic equations and restrictive assumptions
• 3. The role of pressure: Burgers-like equations
  • Zel'dovich's approximation
  • Adhesion approximation
  • Isothermal model
  • Adiabatic model
  • Cosmogenetic model
• 4. The role of noise: emergence of a KPZ-like equation
  • 4.1. Discussion of Eq. (26)
• 5. The linear theory revisited
• 6. Conclusions
• Acknowledgements
• Appendices
  • A: adiabatic approximation
    • A.1. Einstein-de Sitter background (, )
    • A.2. Background cosmologies with ,
  • B: linear regime
• References

© European Southern Observatory (ESO) 1999

Online publication: September 2, 1999
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