Volume 401, Number 3, April III 2003
|Page(s)||895 - 901|
|Published online||01 April 2003|
The nature of the absorbing torus in compact radio galaxies
INAF - Osservatorio Astrofisico di Arcetri, Largo E. Fermi 5, 50125 Firenze, Italy
2 Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138, USA
3 Observatoire de Haute-Provence, CNRS, 04870 Saint-Michel l'Observatoire, France
Corresponding author: G. Risaliti, firstname.lastname@example.org
Accepted: 21 January 2003
We present BeppoSAX observations of the two radio galaxies PKS 1934-63 and S5 1946+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”.
Key words: galaxies: active / X-rays: galaxies
© ESO, 2003
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