Left: L_IR vs. T_dust diagram, plotted against the larger sample of Symeonidis et al. (2013, orange dots), that of Magdis et al. (2010, green circles), and the SMG sample of (Magnelli et al. 2012a, blue diamonds). cB58 and the poorly constrained Cosmic Eye are shown by black squares surrounded by a diamond. Our sample (large hollow diamonds) has warmer T_dust compared to galaxies with same luminosity at lower redshift. Our sample has similar temperatures to the ULIRG sample of Magdis et al. (2010), indicating overall warmer temperatures at z ~ 2 or more than in the more local Universe. The SMGs that lie closest to our sample in this parameter space and appear warmer than the main SMG trend are among the most strongly lensed ones in the Magnelli et al. (2012a) sample, suggesting we have similar objects in our two surveys. The three dashed curves represent the PACS160 5σ detection limits at the redshifts mentioned below them. The smaller hollow color-coded diamonds represent the observed (lensed) luminosities of our sources, which we can see lie well above their corresponding limiting curves. Right: redshift vs. T_dust diagram. Our sample lies together the z ~ 2 ULIRGs and with many of the SMGs at same redshift. Compared to the latter in particular, our sample has similar temperatures with the SMGs that are in the ULIRG − HyLIRG regime, again indicating no strong evolution of T_dust with L_IR at the considered redshifts. The rainbow colored curves represent, from left to right, the 5σ limits in T_dust per redshift for an object of respective L_IR = [1,2,4,6,8,10 × 10¹² L_⊙]. This illustrates that for their corresponding luminosities and redshifts, our objects lie way above the minimal detectable T_dust.