Slope of the IGIMF at the low-mass end, specifically when the IGIMF was fitted with power laws in the mass ranges [0.01, 0.1] M_⊙ and [0.01, 0.3] M_⊙ (upper subpanel), and the slope of the IGIMF at the high-mass end when the IGIMF was fitted with a power law in the mass ranges [0.5, 10] M_⊙ and [1, 10] M_⊙ (lower subpanel) These calculations are based on the models presented in Fig. 1.