Evolution of Perturbations in a Baryon-dominated Universe: Gauge-invariant Analysis
Abstract
The evolution of scalar (density) perturbations in a baryon-dominated universe is comprehensively studied on the basis of a gauge-invariant method. In particular, the residual anisotropies of the cosmic microwave background radiation are calculated and are compared with the recent observational upper limits. To the extent that the universe has not been reionized after recombination, the observed upper limits of the temperature anisotropies on small angular scales rule out the cosmological models without nonbaryonic dark matter. In turn, this would provide a strong raison d'etre for (nonbaryonic) dark matter, independently of the results of standard primordial nucleosynthesis. Reionization after recombination, if any, might allow an isocurvature baryonic universe as a viable model, only when the initial density power spectrum was very steep.
- Publication:
-
The Astrophysical Journal
- Pub Date:
- June 1989
- DOI:
- 10.1086/167516
- Bibcode:
- 1989ApJ...341..557G
- Keywords:
-
- Baryons;
- Computational Astrophysics;
- Gauge Invariance;
- Perturbation Theory;
- Relic Radiation;
- Astronomical Models;
- Dark Matter;
- Universe;
- Astrophysics;
- COSMIC BACKGROUND RADIATION;
- COSMOLOGY;
- EARLY UNIVERSE