Overview of the model for the radio and far-infrared emission with which the q parameter can be calculated. The input parameters, redshift z and total stellar mass M_⋆, are shown on the left and the final output is the q parameter that combines 1.4 GHz luminosity L_1.4 and the rest-frame 8 − 1000 μm luminosity L_IR. For the galactic scale height, H_gal, different scenarios are considered which is indicated by the dashed lines; see Sect. 2.1.3. Free parameters of the model are highlighted by yellow boxes and their default values are listed in Table 1. See Sect. 2 for details of the model.