SEMIEMPIRICAL SEEDED ISOCURVATURE COSMOGONIES

Main predictions of the baryon isocurvature model for structure formation are reproduced if the primeval entropy per baryon is constant and homogeneity is broken by a clumpy distribution of seed masses. The constant entropy per baryon may reconcile the cosmogony with the standard model for the origin of the light elements. The seeds could be long-lived cosmic field structures or inhomogeneously produced nonbaryonic cold dark matter, if the needed primeval space distribution could be arranged. The constraints from the large-scale distributions of galaxies and the thermal cosmic background radiation require OMEGA approximately 0.1. In some cases the primeval seed rms mass constrast deltarho(c)/rho(c) exceeds unity on the scale of clusters of galaxies, meaning the fluctuations cannot be Gaussian, which could permit cluster formation in a low-density universe.