Polarized intensity map (not deconvolved) of the reference source (named 02, see text for details) (top panels) and of the source named 09 (bottom panels) before (left) and after (right) applying the stacking technique. Green contours showing the polarized intensity start at 3σ_QU,ref and increase by factors of . The orange circles in the bottom left corners represent the synthesized beam FWHM of the polarization observations (20′′).