Cosmological Perturbations in the Early Prematter Universe
Abstract
In the framework of a singularityfree, spatially closed cosmological model of the universe, small perturbations in the preradiation periods are considered. It is assumed that the perturbation has spherical symmetry and is confined to a small spatial region. The procedure is carried out in a generalized de Donder gauge. Firstorder field equations for the perturbations are derived from Einstein equations. A compatibility condition between the contracted Bianchi identity and the de Donder condition is used in order to restrict the family of available perturbation metric functions. The mass of the perturbation is expressed in terms of the radius of the universe. It is found that a perturbation may emerge either at the beginning of the present expansion phase of the universe or during the transition period, when the universe was extremely hot. It is shown that this formation will pass the prematter and transition periods in a smooth mathematically wellbehaved manner and then enter the radiation period becoming a pregalactic perturbation.
 Publication:

The Astrophysical Journal
 Pub Date:
 November 1994
 DOI:
 10.1086/174788
 Bibcode:
 1994ApJ...435....8I
 Keywords:

 Astronomical Models;
 Cosmology;
 Einstein Equations;
 Matter (Physics);
 Perturbation Theory;
 Universe;
 Galactic Evolution;
 Mathematical Models;
 Astrophysics;
 COSMOLOGY: EARLY UNIVERSE;
 COSMOLOGY: THEORY