Exploring two-spin internal linear combinations for the recovery of the CMB polarization

Understand

We present a methodology to recover cosmic microwave background (CMB) polarization in which the quantity $P = Q+ iU$ is linearly combined at different frequencies using complex coefficients.

• This is the most general linear combination of the $Q$ and $U$ Stokes parameters which preserves the physical coherence of the residual contribution on the CMB estimation.
• The approach is applied to the internal linear combination (ILC) and the internal template fitting (ITF) methodologies.
• The variance of $P$ of the resulting map is minimized to compute the coefficients of the linear combination.