[C II]-to-FIR luminosity ratio vs. FIR luminosity. Plotted are values for starburst galaxies and active galactic nuclei (AGNs) in the local universe and at high redshift and for local ULIRGs (Maiolino et al. 2005; Walter et al. 2009; Díaz-Santos et al. 2013; Venemans et al. 2016; Mazzucchelli et al. 2017 and references therein). The value for J1342+0928 is plotted as a red star. The dashed line indicates the median ﹩{L}_{[{\rm{C}}{\rm{II}}]}﹩/﹩{L}_{\mathrm{FIR}}﹩ ratio of local star-forming galaxies (Díaz-Santos et al. 2013).