Separating CMB Stokes Q and U polarization signals from Non-Gaussian
  Emissions
  In this paper we estimate diffuse foreground minimized Cosmic Microwave
Background (CMB) Stokes Q and U polarization maps based upon the fundamental
concept of Gaussian nature of CMB and strong non-Gaussian nature of
astrophysical polarized foregrounds using WMAP nine year published polarization
maps. We excise regions of the sky that define position of the known point
sources, regions that are strongly contaminated by either the detector noise or
by the diffuse foregrounds or both, and then perform foreground minimizations
over the surviving sky regions that constitute approximately $50\%$ of the full
sky area. We critically evaluate performance of foreground minimizations in
several ways and show that our foreground minimization method removes
significant foregrounds from input maps. The cleaned Stokes \{Q, U\}
polarization maps have less EE and BB power from relevant sky region compared
to WMAP foreground-reduced Stokes \{Q, U\} polarization maps at different
multipole ranges. We validate our methodology by performing detailed Monte
Carlo simulations. The main driving machinery of our method is an
internal-linear-combination (ILC) approach, however, unlike simple variance
minimization performed in usual ILC method, the core of the method being
dependent on the theoretically well motivated concept of Gaussianity of CMB
polarization a direct connection is established between observations and models
of inflation. Additionally, the method, like the usual ILC method, is
independent on modeling uncertainties of polarized foregrounds. It will be
useful to apply our method in future generation low-noise CMB polarization
experiments.
