Azimuthal (angles computed east of north) variation of the P_I (top row) and P (bottom row) images, for the H (left column) and Ks bands (right column). The position of the telescope’s spiders is indicated by the dashed lines. In the P plot at H band, the stars and the triangles represent the lower and upper limits of P (see text for a detailed explanation). The P image at K_s band is too contaminated by artifacts (see Fig. 3, right-bottom plot).