Broadband study of hard X-ray selected absorbed AGN
  [Abridged]We report on the broadband X-ray properties of a complete sample of
absorbed Seyfert galaxies hard X-ray selected with INTEGRAL. The sample is
composed of 33 sources: 15 are newly discovered above 20 keV while 18 are
already known AGN. For 17 sources we have performed a broadband analysis with
XMM and INTEGRAL data. We have complemented the analysis of the 16 remaining
sources with existing broadband studies. The spectra are well reproduced with
an absorbed primary emission with a high energy cutoff and its scattered
fraction below 2-3 keV, plus the Compton reflection features. A high energy
cut-off is found in 30% of the sample, with an average value below 150 keV. The
hard X-ray selection favours the detection of more obscured sources, with the
log NH average value of 23.15. The diagnostic plot NH vs
F(corr)(2-10keV)/F(20-100keV) allowed the isolation of the Compton thick
objects and may represent a useful tool for future hard X-ray observations of
newly discovered AGN. We are unable to associate the reflection components
(continuum and Fe line) with the absorbing gas as a torus, a more complex
scenario being necessary. In the Compton thin sources, a fraction (but not all)
of the Fe line needs to be produced in a gas located closer to the BH than the
thick torus, and this is possibly associated with the optical BLR, responsible
also for the absorption. We still need a Compton thick medium (not intercepting
the line of sight) likely associated to a torus, which contributes to the Fe
line and produces the observed reflection continuum above 10 keV. The
Iwasawa-Taniguchi effect can not be confirmed with our data. Finally, the
comparison with a sample of unobscured AGN shows that, type 1 and type 2 (once
corrected for absorption) Seyfert are characterized by the same
nuclear/accretion properties (luminosity, bolometric luminosity, Eddington
ratio), supporting the unified view.
