Microwave Background Anisotropies in Primeval Isocurvature Baryon Models: Constraints on the Cosmological Parameters

Abstract

We have performed the most comprehensive predictions of the temperature fluctuations \dtt in the primeval isocurvature baryon models to see whether or not the models are consistent with the recent data on the cosmic microwave background anisotropies. More specifically, we computed the \dtt corresponding to the experimental set-up by the South-Pole and the Owens Valley experiments as well as the COBE satellite. The amplitudes of the predicted \dtt are normalized by means of the COBE 10$^\circ$ data. The resulting constraints on the models are presented on $n - Ω_b$ plane in the case of $λ_0=1-Ω_b$ (flat models) and $λ_0=0$ (open models), where $n$ is the primordial spectral index of entropy fluctuations and $Ω_b$ is the present baryon density parameter. Our results imply that the PIB models cannot be reconciled with the current observations for any reasonable set of cosmological parameters.