Chandra and NuSTAR follow-up observations of Swift-BAT selected AGN
  Based on current models of the Cosmic X-ray Background (CXB), heavily
obscured Active Galactic Nuclei (AGN) are expected to make up ~10% of the peak
emission of the CXB and ~20% of the total population of AGN, yet few of these
sources have been recorded and characterized in current surveys. Here we
present the Chandra follow-up observation of 14 AGN detected by Swift-BAT. For
five sources in the sample, NuSTAR observations in the 3-80 keV band are also
available. The X-ray spectral fitting over the 0.3-150 keV energy range allows
us to determine the main X-ray spectral parameters, such as the photon index
and the intrinsic absorption, of these objects, and to make hypotheses on the
physical structures responsible for the observed spectra. We find that 13 of
the 14 objects are absorbed AGN, and one is a candidate Compton thick AGN,
having intrinsic absorption NH>1E24 cm^{-2}. Finally, we verified that the use
of NuSTAR observations is strategic to strongly constrain the properties of
obscured AGN, since the best-fit values we obtained for parameters such as the
power-law photon index and the intrinsic absorption NH changed sometimes
significantly fitting the spectra with and without the use of NuSTAR data.
