INTEGRAL view of AGN

• Main Authors: Malizia, Angela, Sazonov, Sergey, Bassani, Loredana, Pian, Elena, Beckmann, Volker, Molina, Manuela, Mereminskiy, Ilya, Belanger, Guillaume
• Format: Journal Article
• Language: English
• Published: 07-09-2020
• Subjects: Physics - High Energy Astrophysical Phenomena
• DOI: 10.48550/arxiv.2009.03232

AGN are among the most energetic phenomena in the Universe and in the last
two decades INTEGRAL's contribution in their study has had a significant
impact. Thanks to the INTEGRAL extragalactic sky surveys, all classes of soft
X-ray detected (in the 2-10 keV band) AGN have been observed at higher energies
as well. Up to now, around 450 AGN have been catalogued and a conspicuous part
of them are either objects observed at high-energies for the first time or
newly discovered AGN. The high-energy domain (20-200 keV) represents an
important window for spectral studies of AGN and it is also the most
appropriate for AGN population studies, since it is almost unbiased against
obscuration and therefore free of the limitations which affect surveys at other
frequencies. Over the years, INTEGRAL data have allowed to characterise AGN
spectra at high energies, to investigate their absorption properties, to test
the AGN unification scheme and to perform population studies. In this review
the main results are reported and INTEGRAL's contribution to AGN science is
highlighted for each class of AGN. Finally, new perspectives are provided,
connecting INTEGRAL's science with that at other wavelengths and in particular
to the GeV/TeV regime which is still poorly explored.