Predicted BC03 tracks in the NUVrK diagram at 0.2 <z< 0.5 for Z = 0.008 (Calzetti et al. 2000) and E(B−V) = 0.2. The arrow shows the shift expected for E(B−V) + 0.1. Analogously to Fig. 8, the black solid and dashed lines correspond to the limits of the green valley and its middle, respectively, while we report the (r−K_s)°-limit of the ℳ^⋆-quenching channel with a vertical magenta solid line. The grey contours outline the galaxy density distribution. Each marker is coloured with respect to the corresponding stellar age (in Gyr). Left panel: only one quenching time is considered: t_Q = 1 Gyr, with τ = 0.1 Gyr (triangles), τ = 0.25 Gyr (squares), τ = 1 Gyr (inverted triangles), τ = 1.5 Gyr (circles), and τ = 2.5 Gyr (diamonds). Right panels: two quenching timescales are considered: τ = 0.1 Gyr (middle panel) and τ = 1 Gyr (right panel), for t_Q = 1 Gyr (triangles), 2 Gyr (diamonds), 5 Gyr (squares), and 9 Gyr (inverted triangles). The filled circles show the track for a continuous star formation without quenching. The red solid line linking the black edge triangles shows the track for t_Q = 9 Gyr and τ = 0.5 Gyr.