Perturbations of a Universe Filled with Dust and Radiation
Abstract
A first-order perturbation approach to k=0 Friedmann cosmologies filled with dust and radiation is developed. Adopting the coordinate gauge comoving with the perturbed matter, and neglecting the vorticity of the radiation, a pair of coupled equations is obtained for the trace h of the metric perturbations and for the velocity potential v. A power series solution with upwards cutoff exists such that the leading terms for large values of the dimensionless time agree with the relatively growing terms of the dust solution of Sachs and Wolfe.
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