Stellar populations in Active Galactic Nuclei III

In this paper we apply the stellar population synthesis method previously described in Boisson et al. ( 2000) to five more AGN. The analysis of these new data strengthen our previous conclusions: i) homogeneity of the stellar population within a class of nuclear activity regardless of the morphological type of the host galaxy; ii) populations within the nuclear regions of LINERs and Seyfert 2s are different: LINERs have a very old metal-rich population while in the Seyfert 2s a contribution of a weak burst of star formation is observed together with the old high metallicity component; iii) in the circum-nuclar region (200 pc less than or equal to D less than or equal to 1 kpc) of all the active galaxies in our sample, except for NGC 2992, we detect an old burst of star formation (0.2-1 Gyr), which is contrary to what is observed in normal galaxies. We note that the broad OIlambda8446 Angstrom emission line detected in the spectrum of the nucleus of NGC 2992 confirms its classification as a Seyfert 1.