Velocity dispersion obtained as function of the additive polynomial degree in PPXF. We show here the results obtained using α-enhanced SSP, and we refer the reader to Appendix B to see the effect that changing [α/Fe] has on the resulting velocity dispersion values. The results stabilise, for all the galaxies around ADEGREE ∼ 20, which is the final choice we adopted for the results given in Table 3.