3.3 Microwave Background3 Physical Cosmology3.1 The Standard Model

3.2 Newtonian Order Perturbations 

The large (galaxy and cluster) scale inhomogeneities are generally described by Newtonian order, scalar type perturbations of the FLRW spacetimes, assuming spatial scales much smaller than the horizon radius, peculiar velocities small compared to the speed of light, and a gravitational potential that is both much smaller than unity (in geometric units) and slowly varying in time. A comprehensive review of the theory of cosmological perturbations can be found in [51].

Many numerical techniques have been developed to solve the hydrodynamic and collisionless particle equations in this limit. For the hydrodynamic equations, the methods range from Eulerian finite difference techniques [8, 18, 56] to unstructured particle methods [29, 34]. For the collisionless particle or dark matter equations, the canonical choices are treecodes or PM and P tex2html_wrap_inline902 M methods [36], although many variants have been developed to optimize computational performance and accuracy, including grid and particle refinement methods. The reader is referred to [39] for a comparison of several different numerical methods applied to a common problem of structure formation. A method for solving non-equilibrium, multi-species chemical reaction flows together with the hydrodynamic equations in a background FLRW model is described in [1, 9].



3.3 Microwave Background3 Physical Cosmology3.1 The Standard Model

image Physical and Relativistic Numerical Cosmology
Peter Anninos
http://www.livingreviews.org/lrr-1998-2
© Max-Planck-Gesellschaft. ISSN 1433-8351
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