Linear polarisation degree P_L in the 2-8 keV band for the wedge torus model described in Sect. 4.1 as a function of the torus covering factor CF = cos θ and the observer inclination cos i. The different panels represent different values for the torus column density N_H. Positive P_L values (red) denote polarisation in the vertical direction of the observer frame (γ = 0°). Negative P_L values (blue) denote polarisation in the horizontal direction of the observer frame (γ = 90°). The dotted line separates obscured and unobscured sightlines.