Polarimetric differential imaging data of HD 172555 with the VBB filter (590–880 nm). The 8 × 8 binned images show polarized flux computed as Stokes I (left column), Q_φ (middle column), and U_φ (right column) parameters. Top row: observation OBS177_0010-0042 (see Table 1 for the observational conditions) data averaged over 8 QU cycles. Middle row: observation OBS249_0028-0060 data averaged over 6 QU cycles. Bottom row: average of the data presented in the top and middle rows. The position of the star is denoted by a yellow asterisk. White arrows point out quasi-static speckles from the AO system. In all images north is up and east is to the left. The color bars show the counts per binned pixel.