Stellar population properties for a sample of hard X-ray AGNs
  The aim of this paper is to study the stellar population of galaxies hosting
an active galactic nucleus (AGN). We studied a sub-sample of hard X-ray
emitting AGNs from the INTEGRAL and Swift catalogs which were previously
identified and characterized through optical spectroscopy. Our analysis
provides complementary information, namely age and metallicity, which is
necessary to complete the panoramic view of such interesting objects.
  We selected hard X-ray emitting objects identified as AGNs by checking their
optical spectra in search for absorption lines suitable for the stellar
population analysis. We obtained a final sample consisting of 20 objects with
redshift lower than 0.3. We used the full-spectrum fitting method and, in
particular, the penalized pixel one applying the PPXF code. After masking all
the regions affected by emission lines, we fitted the spectra with the MILES
single stellar population templates and we derived mass-weighted ages and
metallicities.
  Most of the objects in our sample show an old stellar population, but three
of them are characterized by a bimodal distribution with a non negligible
contribution from young stars. The values of the mass-weighted metallicity span
a large range of metallicity with most of them slightly above the solar value.
No relations between the stellar population properties and the morphological
ones have been found.
