High precision modeling of polarized signals: Moment expansion method generalized to spin-2 fields

The modeling and removal of foregrounds poses a major challenge to searches for signals from inflation using the cosmic microwave background (CMB). In particular, CMB including various spatial averaging effects introduces multiple complications that will have be accounted in upcoming analyses. this work, we introduce generalization intensity moment expansion spin-2 field linear polarization: spin-moment expansion. Within framework, moments become objects are directly related underlying spectral parameters polarization angle distribution functions. obtaining required expressions modeling, highlight similarities differences with methods. A spinor rotation complex plane frequency naturally arises first order when signal contains both variations. Additional dependencies introduced at higher order, demonstrate how these can several illustrative examples. Our new polarized reveals powerful tool model dependence angle. As such, it immediately applied numerous astrophysical situations.