Spectral dependence of the toy model filament polarized power spectra. Left: polarized power spectra divided by the pivot-modified blackbody squared for the special case of ψ^bg = 30°. All spectra are normalized with respect to their value at ν₀. The signals are shown in color: EE/BB (red), EE (blue), BB (green), and EB (orange). The black dashed lines were recovered by deriving the moment power spectra from the spin-moment maps. Right: close up view on . The black curve represents the best-fit of Eq. (30).