Faint polarization artifacts in the maps Q_ϕ(x, y), Q(x, y), U(x, y) of the Ring0 model r₀ = 201.6 mas produced by the axisymmetric PSF_AO(x, y) (left column) and a 2D single-frame speckle PSF₁ of an AO system (right column). Dashed circles are indicated for the PSFs and the Stokes U maps to indicate the location of the halos produced by the speckle ring. The color scale is strongly saturated in the center of the main maps, and therefore this region is plotted as inset in the lower right with a 200 times wider color scale.