Plot of R_1/2, mod and of L_3000, mod vs. log(M_BH) (upper and lower panels, respectively) in the case of a NT disc (left panels), the NT/X model (middle panels), and the NT/X+fcol model (right panels). Black and red points in the top left panel show the half-light radius for disc inclination 30 and 60 degrees, respectively. Black and red points in the bottom panels indicate the model predictions for θ = 30° and θ = 60°, respectively (R_1/2, mod are almost identical for both inclinations). Lines show the best fits to the data, and the 1-σ confidence regions (see text for details).