Kennicutt–Schmidt law between star formation rate and molecular gas mass surface density. The large blue and red dot show the position of 3C 326 N when using the mass surface density of cold molecular gas probed by CO(1–0) and H₂ 0–0 lines, respectively. For the latter estimate, the black line shows the range of surface-brightness observed with MIRI. Small empty circles show several sets of normally star-forming galaxies in the nearby Universe taken from Fischer et al. (2013), Kennicutt (2020), and Saintonge et al. (2013). Green and grey squares show the MOHEGs of Ogle et al. (2010) and Alatalo et al. (2015).