Modeling Dynamical Dark Energy
Abstract
Cosmological models with different types of dark energy are becoming viable alternatives for standard models with the cosmological constant, yet such models are more difficult to analyze and to simulate. We present analytical approximations and discuss ways of making simulations for two families of models, which cover a wide range of possibilities and include models with both slow and fastchanging ratio w=p/ρ. More specifically, we give analytical expressions for the evolution of the matter density parameter Ω_{m}(z) and the virial density contrast Δ_{c} at any redshift z. The latter is used to identify halos and to find their virial masses. We also provide an approximation for the linear growth factor of linear fluctuations between redshift z=40 and 0. This is needed to set the normalization of the spectrum of fluctuations. Finally, we discuss the expected behavior of the halo mass function and its time evolution.
 Publication:

The Astrophysical Journal
 Pub Date:
 December 2003
 DOI:
 10.1086/379236
 arXiv:
 arXiv:astroph/0303303
 Bibcode:
 2003ApJ...599...24M
 Keywords:

 Cosmology: Theory;
 Cosmology: Dark Matter;
 Galaxies: Clusters: General Methods: Analytical;
 Methods: Numerical;
 Astrophysics
 EPrint:
 10 pages, 10 figures ApJ submitted