3 Physical Cosmology 

The phrase ``physical cosmology'' is generally associated with the large (galaxy and cluster) scale structure of the post-combination epoch where gravitational effects are modeled approximately by Newtonian physics on an uniformly expanding, matter dominated Friedmann-Robertson-Lemaître-Walker (FLRW) background. A discussion of the large scale structure is included in this review since any viable model of our Universe which allows a regime where strongly general relativistic effects are important must match onto the weakly relativistic (or Newtonian) regime. Also, since certain aspects of this regime are directly observable, one can hope to constrain or rule out various cosmological models and/or parameters.

Due to the vast body of literature on numerical simulations of the post-combination epoch, it is possible to mention only a small fraction of all the published papers. Hence, the following summary is limited to cover just a few aspects of computational physical cosmology, and in particular those that can potentially be used to discriminate between cosmological model parameters, even within the realm of the standard model.

• 3.1 The Standard Model
• 3.2 Newtonian Order Perturbations
• 3.3 Microwave Background
• 3.4 Gravitational Lensing
• 3.5 Ly Forest
• 3.6 Galaxy Clusters

Physical and Relativistic Numerical Cosmology Peter Anninos http://www.livingreviews.org/lrr-1998-2 © Max-Planck-Gesellschaft. ISSN 1433-8351 Problems/Comments to livrev@aei-potsdam.mpg.de