Ratio between the observed L_IR and the L_IR before the truncation of the SFH as a function of the age of truncation of the SFH (age_trunc). Circles are galaxies from the COSMOS quenched sample, the red ones are galaxies confirmed from their spectra. Diamonds indicate galaxies for which IR data are available. Cyan squares are galaxies from the local HRS quenched galaxies. The light grey shaded region indicates the region covered by the UV–NIR SED models used to determine the physical properties of the galaxies. The coloured tracks indicate an exponential decrease in / as a function of age_trunc assuming different e-folding times.