Study of the Stellar Populations in AGN

Summary

We present here preliminary results of a study of the stellar population in AGN. Our aim is to quantify the stellar population within the nuclear regions by means of spectroscopic observations and to determine whether the central activity influences the stellar population or vice versa. The results will have general relevance to understanding the evolution of galaxies and the energy generation within the nucleus.

Introduction

We have observed 30 galaxies, of different levels of activity, using long-slit spectroscopy at the CFHT, in the range 5000–10000 Å (including MgI, NaI, TiO, CN and CallT).

In order to determine the composite stellar population of a galaxy, it is necessary to obtain spectroscopy of several different wavelength regions, including a number of different absorption lines. Without such information it is not possible to disentangle the effects of abundance variation, luminosity class and stellar type.

We are able to detect radial gradients in the stellar distribution (if any), as well as the possible dilution in the nucleus of the stellar component by a featureless component. We shall then establish at what wavelengths and to what degree the stellar population is responsible for the observed activity.

Results and Conclusions

Preliminary results for NGC 3516 (type 1 Seyfert, SB0/a), Mkn 620 (type 2 Seyfert, S(B)a) and NGC 3379 (non-active galaxy, E0) are presented.