4 research outputs found
Large-angle Polarization of the Cosmic Microwave Background Radiation and Reionization
We discuss the effect of matter reionization on the large-angular-scale
anisotropy and polarization of the cosmic microwave background radiation (CMBR)
in the standard CDM model. We separate three cases in which the anisotropy is
induced by pure scalar, pure tensor, and mixed metric perturbations
respectively. It is found that, if reionization occurs early enough, the
polarization can reach a detectable level of sequentially , , and
of the anisotropy. In general, a higher degree of polarization implies
a dominant contribution from the tensor mode or reionization at high redshift.
Since early reionization will suppress small-scale CMBR anisotropies and
polarizations significantly, measuring the polarization on few degree scales
can be a direct probe of the reionization history of the early universe.Comment: Changes in the revised version: 1. Below Eq. (2), we demonstrate the
method of our numerical work, by adding the evolution equations for the
Legendre coefficents for both the scalar and tensor mode pertubations. 2.
Below Eq. (9), we added a paragraph on discussing the basis we employed in
computing the polarization correlation function. 3. In Sec. 4, we have
rewritten the first and second paragraphs, where we illustrate how to the
explain the discrepancies with the previous wor