Orbital profiles of the flux and of the normalized Stokes parameters of A0620−00. Solid blue and empty red circles correspond to the data from two different orbits. Panel (a): Photometric R magnitudes of A0620−00 folded with the orbital period. Panels (b) and (c): Observed normalized Stokes parameters. Panel (d): Intrinsic PD of A0620−00 in the R filter folded with the orbital period. Each circle with a 1σ error bar shows the 35-minute average polarization.