Relation between L_IR and for field galaxies (upper panel) and cluster (lower panel) galaxies. The orange circles show the sample of nearby galaxies defined in Sect. 2. The light green diamonds show the intermediate redshift cluster galaxies from this work, the dark green diamonds are those from Geach et al. (2009a, 2011). The purple circles show z > 1 galaxies in clusters (Wagg et al. 2012) and in the field (Daddi et al. 2010). Pink identifies the Tacconi et al. (2010) sample of normal galaxies at z ~ 1.4 and z ~ 2. In both panels, the line shows the fit of the relation for the field galaxies over the full IR luminosity range, ) = 0.52 × log ₁₀ (L_IR) + 3.61.