Measuring Polarization in the Cosmic Microwave Background

摘要

Polarization induced by cosmological scalar perturbations leads to a typical anisotropy pattern, which can best be analyzed in a Fourier domain. This allows one to distinguish a cosmological signal of polar- ization unambiguously from other foregrounds and systematics, as well as from polarization induced by nonscalar perturbations. The precision with which polarization and cross-correlation power spectra can be determined is limited by cosmic variance, noise, and foreground residuals. The choice of estimator can significantly improve our capability of extracting a cosmological signal, and in the noise-dominated limit the optimal power spectrum estimator reduces the variance by a factor of 2 compared to the simplest estimator.