Schematic representation of the SED fitting procedure performed in this study. N_param is the number of free parameters assumed in the models: relative mass fraction of PAHs, VSGs, and BGs, the scale factor of the ISRF, and a scale factor to describe the contribution of the old stellar population to the NIR-continuum. PDF is the probability density function obtained assuming an uniform prior distribution of the initial parameters. F_mod (band), and F_obs (band) are the corresponding modelled and observed fluxes in each band.