The nature of the absorbing torus in compact radio galaxies

We present BeppoSAX observations of the two radio galaxies PKS 1934-63 and S5 1916+708. Strong Iron Kα lines are detected in both objects indicating that the two sources are absorbed by column densities higher than 1024 cm-2. Combining radio continuum, HI absorption and X-ray data we can constrain the physical state and the dimensions of the absorber. We find that the putative obscuring torus is molecular and located at a distance higher than 20 pc from the center in S5 1946+70. In PKS 1934-63 no radio nucleus has been observed. If this is due to free-free absorption a radius of only a few pc is inferred. Since the Kα lines have been detected only at 90% confidence, we also discuss the implications if they would be not as strong as found from our data. From our results it appears that the combination of hard X-ray data and spatially resolved HI absorption measurements provides a powerful diagnostic for conditions in the absorbing torus.