Patrick Valageas web page

In usual cosmological scenarios the large-scale structures which we observe in the present universe (galaxies, clusters,..) have formed by gravitational instability from small initial density fluctuations. The dynamics of this system is well understood in the linear regime (where the amplitude of the perturbations is small) because one can use perturbative methods. However the non-linear regime remains an open problem. Although this topic is often tackled with numerical simulations most of my work has focused on analytical approaches to this problem (theoretical study of the equations of motion or development of phenomenological models).

Articles:

• 2004, submitted to MNRAS
  A simple model for the probability distribution of the density field, from the quasi-linear to the highly non-linear regime, which is consistent with all known exact results.
  
• 2004, A&A, 421, 23
  A theoretical study of the Vlasov-Poisson equations which govern the gravitational dynamics in an expanding universe: large N expansions.
  
• 2002, A&A, 385, 761 ,    2002, A&A, 382, 450 ,    2002, A&A, 382, 431 ,    2002, A&A, 382, 412 ,    2002, A&A, 379, 8
  These articles mainly investigate the application of a steepest-descent method to the formation of large-scale structures from the equations of motion.
  
• 2000, MNRAS, 311, 234 ,    1997, A&A, 328, 435
  A comparison of a "stable-clustering" model with numerical simulations, for the density distribution and multiplicity functions. A detailed theoretical study of this model.
  
• 1999, A&A, 347, 757
  Description of the non-linear density field in terms of fractals.
  
• 1998, A&A, 337, 655
  A model for the density distribution based on a spherical dynamics approximation.