Phenomenological polarization angle model, φ_X, for the pulsar in the X-rays considering positive and negative phase shifts from −5% to 5% at the interpulse (upper panel) and main pulse (lower panel). For reference, the dotted black line shows the optical (V-band) polarization angle, and the solid red curve shows the I Stokes (V-band, with arbitrary normalization) from Słowikowska et al. (2009). The phase shifts are applied within the boundaries indicated by the vertical dashed blue lines.