The depletion timescale versus redshift of our sources, compared with other SPT-SMGs and other high-z SMGs. The depletion timescales for our sources are computed with the gas mass estimated from low-J CO fluxes with an α_CO = 0.8. The grey shaded region represents the evolution of the depletion timescale with redshifts for main sequence galaxies. This plot is adapted from Jarugula et al. (2021). The high-redshift gravitationally lensed SPT-SMGs are from Aravena et al. (2016) and Reuter et al. (2020) and the other high-redshift SMGs are taken from Carilli et al. (2010), Walter et al. (2012), Fu et al. (2012, 2013), Ivison et al. (2013), Alaghband-Zadeh et al. (2013). The main sequence galaxies are described in Saintonge et al. (2013) as t_dep = 1.5 (1 + z) α, where α is from −1.5 (Davé et al. 2012) to −1.0 (Magnelli et al. 2013), which is shown as the grey shaded region.