BEPPOSAX OBSERVATIONS OF 2 JY LOBE-DOMINATED BROAD-LINE SOURCES - THEDISCOVERY OF A HARD X-RAY COMPONENT

We present new BeppoSAX LEGS, MECS, and PDS observations of five lobe- dominated, broad-line active galactic nuclei selected from the 2 Jy sa mple of southern radio sources. These include three radio quasars and two broad-line radio galaxies. ROSAT PSPC data, available for all the objects, are also used to Letter constrain the spectral shape in the s oft X-ray band. The collected data cover the 0.1-10 keV energy range, reaching 40 keV for one source. Detailed spectral fitting shows that a ll sources have a flat hard X-ray spectrum with energy index alpha(x) similar to 0.75 in the 2 - 10 keV energy range. This is a new result, which is at variance with the situation at lower energies where these sources exhibit steeper spectra. Spectral breaks similar to 0.5 at 1 - 2 keV characterize the overall X-ray spectra of our objects. The flat , high-energy slope is very similar to that displayed by flat-spectrum /core-dominated quasars, which suggests that the same emission mechani sm (most likely inverse Compton) produces the hard X-ray spectra in bo th classes. Contrary to the optical evidence for some of our sources, no absorption above the Galactic value is found in our sample. Finally , a (weak) thermal component is also present at low energies in the tw o broad-line radio galaxies included in our study.