Upper panel: log(L₂₄/L_Ks) vs. Log(L₁₆₀/L_Ks luminosities of the KINGFISH galaxies (shown as filled circles), together with the sample of ETGs from Temi et al. (2009b) shown as filled diamonds. Following Temi et al. (2009a,b) and Davis et al. (2014), L_Ks luminosities are in units of L_⊙, and the IR luminosities in units of erg s⁻¹. KINGFISH galaxies with low sSFR (as in previous figures) are shown with a × superimposed. The color scale corresponds to bins of L_Ks as indicated in the upper left corner. The horizontal dashed line corresponds to the quiescent stellar ratio of L₂₄/L_Ks (Eq. (11)) as defined by Davis et al. (2014). It is evident that galaxies with low sSFR have L₂₄/L_Ks ratios close to the quiescent value. Lower panel: log(L₂₄) vs. Log(L_Ks) with the Davis et al. (2014) relation (Eq. (11)) shown as a dashed line. Symbols are the same as in the upper panel.