SFR as a function of the molecular gas mass, M_H2. The symbols for our sample are the same as in Fig. 12. We compare our results with the WISSH sample (Bischetti et al. 2021), with 1 < z < 1.5 QSOs (pink dots), and with z ∼ 0 sources such as galaxies, ULIRGs, QSOs, AGNs, and narrow-line Seyfert 1 galaxies (symbols and colors in the legend; Saintonge et al. 2011, 2017; Salomé et al. 2023; Shangguan et al. 2020a,b; Rosario et al. 2018; Koss et al. 2021). The gray lines represent fixed values of the gas depletion time (i.e., the inverse of SFE), which is reported at the top of the line. The solid black line is the galaxy main sequence derived by Sargent et al. (2014) considering massive galaxies (M_* > 10¹⁰ M_⊙) up to z ∼ 2.