Small-scale anisotropies in the microwave background in a baryon-dominated open universe

Journal Article · Thu Oct 01 00:00:00 EDT 1987 · Astrophys. J.; (United States)

DOI:https://doi.org/10.1086/184995· OSTI ID:5553396

Gouda, N; Sasaki, M; Suto, Y

The anisotropies of the cosmic microwave background (CMB) radiation in a baryon-dominated universe (BDU) are calculated using a gauge-invariant method. The theoretical predictions on a 4.5-arcmin angular scale are compared with the observational data of Uson and Wilkinson (1984). Both adiabatic and isocurvature scenarios predict roughly the same amplitudes of the anisotropies on this scale, in spite of the difference of the physical mechanism of the anisotropy generation. As a result, CMB isotropy requires that the density parameter of a BDU must be larger than 0.8 even in an isocurvature scenario. This conclusion is compatible with the observation of light elements only if the universe were fairly inhomogeneous at the epoch of primordial nucleosynthesis. In turn, to the extent that standard primordial nucleosynthesis predictions are assumed, the idea of a BDU based on either adiabatic or isocurvature models can be ruled out. 22 references.

• Research Organization: Kyoto Univ., Japan; Hiroshima Univ., Japan; California Univ., Berkeley
• OSTI ID: 5553396
• Journal Information: Astrophys. J.; (United States), Vol. 321
• Country of Publication: United States
• Language: English

Related Subjects

71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
RELICT RADIATION
ANISOTROPY
ADIABATIC PROCESSES
BACKGROUND RADIATION
BARYONS
COMPARATIVE EVALUATIONS
COSMOLOGY
NUCLEOSYNTHESIS
UNIVERSE
ELECTROMAGNETIC RADIATION
ELEMENTARY PARTICLES
FERMIONS
HADRONS
MICROWAVE RADIATION
RADIATIONS
SYNTHESIS
640106* - Astrophysics & Cosmology- Cosmology