Active galactic nuclei in the era of the Imaging X-ray Polarimetry Explorer

In about four years, the National Aeronautics and Space Administration (NASA) will launch a small explorer mission named the Imaging X-ray Polarimetry Explorer (IXPE). IXPE is a satellite dedicated to the observation of X-ray polarization from bright astronomical sources in the 2 - 8 keV energy range. Using Gas Pixel Detectors (GPD), the mission will allow for the first time to acquire X-ray polarimetric imaging and spectroscopy of about a hundred sources during its first two years of operation. Among them are the most powerful sources of light in the Universe: active galactic nuclei (AGN). In these proceedings, we summarize the scientific exploration we plan in the field of AGN using IXPE, describing the main discoveries that this new generation of X-ray polarimeters is expected to make. Among these discoveries, we should see the indisputable detection of signatures of strong gravity, which will help us quantify the effects of scattering by distant cold material on the iron Kα line observed at 6.4 keV. IXPE will also be able to probe the morphology of parsec-scale AGN regions, to evaluate the magnetic field strength in quasar jets and their direction, and, among the most important results, to deliver an independent measurement of the spin of black holes.