Astron. Astrophys. 343, 33-40 (1999)

Reprocessing and variable cold absorption in the broad-line radio galaxy 3C 390.3

P. Grandi ¹, M. Guainazzi ², F. Haardt ³, L. Maraschi ⁴, E. Massaro ⁵, G. Matt ⁶, L. Piro ¹ and C.M. Urry <sup>7

1</sup> Istituto di Astrofisica Spaziale, C.N.R., Area Ricerca di Roma Tor Vergata, I-00133 Roma, Italy
² Astrophysics Division, Space Science Department of ESA, ESTEC, Postbus 299, 2200 AG Noordwijk, The Netherlands
³ Dipartimento di Fisica, Università di Milano, Via Celoria, I-20133 Milano, Italy
⁴ Osservatorio Astronomico di Brera, Via Brera 28, I-20121 Milano, Italy
⁵ Istituto Astronomico, Universita' di Roma, Unita' GIFCO-CNR Roma I, Via Lancisi 29, Roma, Italy
⁶ Dipartimento di Fisica "E.Amaldi", Università degli Studi "Roma 3", Via della Vasca Navale 84, I-00146 Roma, Italy
⁷ Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218, USA

Received 14 May 1998 / Accepted 26 October 1998

Abstract

A BeppoSAX observation of the Broad Line Radio-Galaxy 3C 390.3 is reported. For the first time, both the iron line and a strong reflection hump, produced by the illumination of the primary X-ray emission on cold matter, are detected in this source. The 0.1-100 keV continuum is modeled by an absorbed hard power law () reflected at high energies by material with a fairly large covering factor (). The iron line is centered at keV (rest frame), is intrinsically narrow ( eV), and has an equivalent width of eV.

We discuss the results in the context of current models for AGNs and suggest that the primary X-ray power law continuum is probably produced by a hot inner flow, while the reprocessed radiation comes from an outer cold thin disk, and/or from a thick torus at even larger radii. Further observations with BeppoSAX could distinguish between the latter two cases. Beamed radiation associated to the radio jet is unlikely to contribute significantly to the X-ray emission.

Finally, an historical study of the column density , also reported here, shows that the absorption along the line of sight changes in time. The  time variability, which is not correlated with that of the primary continuum, seems to imply variations of the geometry of the absorber rather than variations in the ionization state of the gas.

Key words: galaxies: active galaxies: individual: 3C 390.3 radio continuum: galaxies X-rays: galaxies

Send offprint requests to: P. Grandi

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Contents

• 1. Introduction
• 2. Data reduction
• 3. Spectral analysis
  • 3.1. Continuum: primary emission and reflection component
  • 3.2. Column density
  • 3.3. Emission line
• 4. Discussion
• 5. Summary
• Acknowledgements
• References

© European Southern Observatory (ESO) 1999

Online publication: March 1, 1999
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