CMB Anisotropies in the Weak Coupling Limit
We present a new, more powerful and accurate, analytic treatment of cosmic
microwave background (CMB) anisotropies in the
weakly coupled regime. Three applications are presented:
gravitational redshifts in a time dependent potential, the Doppler
effect in reionized scenarios, and the Vishniac effect.
The Vishniac effect can dominate primary anisotropies at small
angles even in late and minimally reionized models
in flat dark-matter dominated universes with Harrison-Zel'dovich
initial conditions. The techniques developed here refine
previous calculations yielding a larger coherence angle for the Vishniac
and moreover can be applied to non-trivial ionization histories.
These analytic expressions may be used to modify
results for the standard cold dark matter model to its
and reionized extensions without detailed and time consuming recalculation.
Astronomy & Astrophysics 315 33 (1996)