BeppoSAX Observations of Bright Radio Galaxies

Abstract

BeppoSAX observations of Broad Line Radio Galaxies (BLRGs) have shown that they have a considerable variety of spectral properties and important differences with respect to their radio-quiet counter-part Seyfert 1s. In radio galaxies the soft photons are often absorbed by cold material. In contrast, in Seyfert 1s the soft photons are generally absorbed by warm gas. The iron lines, always detected in Seyfert 1s, are not always present in BLRGs and generally are weak. In addition, small iron line equivalent widths seem to correspond to weak reflection components in radio galaxies. The emerging picture of BLRGs is complex. Probably several X-ray components, jet, accretion flow and molecular torus, mixed in different way in different objects, contribute to the production of their X-ray spectrum and determine the observed variety. The weakness of the reprocessed features can be explained either by a dilution of the Seyfert-like continuum from non-thermal (jet) radiation or by an accretion gas that is hot and geometrically thick close to the black hole and cold geometrically thin (i.e. able to reprocess the primary X-ray radiation) at larger radii.