Blind component separation for polarized observations of the cosmic microwave background

Abstract

Abstract We present in this paper the PolEMICA (Polarized Expectation-Maximization Independent Component Analysis) algorithm which is an extension to polarization of the SMICA (Spectral Matching Independent Component Analysis) temperature multidetectors multicomponents (MD-MC) component separation method. This algorithm allows us to estimate blindly in harmonic space multiple physical components from multidetectors polarized sky maps. Assuming a linear noisy mixture of components we are able to reconstruct jointly the anisotropies electromagnetic spectra of the components for each mode T, E and B, as well as the temperature and polarization spatial power spectra, TT, EE, BB, TE, TB and EB for each of the physical components and for the noise on each of the detectors. PolEMICA is specially developed to estimate the cosmic microwave background (CMB) temperature and polarization power spectra from sky observations including both CMB and foreground emissions. This has been tested intensively using as a first approach full-sky simulations of the Planck satellite polarized channels for a 14-month nominal mission assuming a simplified linear sky model including CMB, and optionally Galactic synchrotron emission and a Gaussian dust emission. Finally, we have applied our algorithm to more realisticPlanck full-sky simulations, including synchrotron, realistic dust and free–free emissions.