Maps showing reduction factor f_red, defined by Eq. (16), as a function of planet mass and orbital distance. The quantity f_red quantifies how much the classical type I migration torque (sum of the Lindblad and static corotation torques) is reduced by the dynamical corotation torque: the latter is negligible where f_red → 1 and strong where f_red ≪ 1. Maps are obtained for four disc models that differ by the choice of the alpha turbulent viscosity (α_vis) and the slope of the density profile (–β). Contour lines are plotted for f_red ∈ [0.3, 0.5, 0.7, 0.9] for better visualisation. The solid white line marks the transition where τ_lib/2 = r_vis (see text). The dashed black line marks the feedback mass (see text). Regions where the planet mass exceeds the thermal mass (equivalent to q_P/h³(r_P) > 1) are excluded as we expect substantial gap opening to occur in low-viscosity discs there.