Radiative Continuum Sources and Dense Line Region in Seyfert Type I Galaxies and Broad Line Radio Galaxies

Abstract

The radiative energy content of Seyfert I galaxies and broad line radio galaxies (BLRG) is reviewed. Most of the power is emitted at far infrared and hard X-ray energies. The variability of the continuum radiation and the life time of the active phase give some information on the source sizes. A lower limit to the size of the X-ray and soft γ-ray sources is given by the opacity to electron scattering and by the efficiency of the electron pair production. The broad line region (BLR) can be responsible for the observed keV absorption. It is also optically thick in the Lyman continuum. Its geometrical configuration is then derived. Free-free absorption in the BLR is very efficient at centimeter wavelengths and the BLR must not surround the compact radio source of the BLRG. The optical and UV absorption lines must arise from regions outside the BLR. The spatial coverage of the Hβ emitting region is large but that of the FeII region may be smaller and may greatly vary between galaxies.