Relationship between the sum of the luminosities of the three aliphatic sub-components (L_3.46 + L_3.51 + L_3.56) and the luminosity of the aliphatic 3.41 μm sub-component (L_3.41) for the AGN-dominated (red circles) and AGN-SF-composite galaxies (red triangles). The gray circles show the relationship for the SFG sample, where the dashed line is the best fit to the data points. The solid line is the relationship between τ_3.46 + τ_3.51 + τ_3.56 and τ_3.41 obtained for the stacked spectrum of the a-C:H absorption AGN sample shown in Fig. 13b.