Wavelength dependence of polarization and physical mechanisms of magnetic field generation in accretion disks around supermassive black holes in active galactic nuclei

Abstract

Analysis of the wavelength dependence of the polarization of radiation from active galactic nuclei (AGNs) is shown to allow the main physical mechanisms of magnetic field generation in accretion disks around supermassive black holes in these objects to be determined. These main processes include the generation of magnetic fields as a result of the equality between the magnetic and radiation pressures or as a result of the equality between the magnetic and gas pressures. In several cases, the wavelength dependence of polarization is shown to be explained, provided that the Shakura-Sunyaev viscosity parameter depends on the accretion-disk radius.