Left: IRX-β diagram of our sample ( cut applied on the free A_V models), with the colorbar indicating the ratio between predicted and observed L_IR’s. Also shown are the Meurer et al. (1999) relation (dashed) and its more recent revision by Takeuchi et al. (2012; solid). Surprisingly, although the sample is IR-selected, it shows a wide range of UV slopes, with an important number of sources appearing “too blue” for their L_IR/L_UV ratios. We can see that the sources for which the L_IR is most underpredicted (blue in the colorbar), are found predominantly on the left of the diagram, meaning they have the bluest slopes. Right: same diagram, this time colored according to the extinction A_V for the same model. Sources on the left of the Meurer relation tend to have less extinction than those at same IRX on the relation.