Linear polarisation fraction for the Auriga 6 reference model with f_S, A = 0.6 and dust allocation recipe recT12 for nine synthetic broad bands and face-on inclination. The black dashes indicate the apparent magnetic field direction perpendicular to the line of sight, obtained by rotating the polarisation direction by 90° . The dotted, dashed and solid contours indicate regions with I > [0.01, 0.05, 0.1]I_max respectively. Pixels with I < 0.001I_max have been masked out. The angular and physical scale are indicated on the bottom of each panel; the latter assumes a distance of 10 Mpc.