XMM-Newton observations of an absorbed z= 0.67 QSO: no dusty torus?
Abstract
We present XMM-Newton observations of AX J0341.4-4453, a mildly reddened AV < 7 quasi-stellar object (QSO) at a redshift of z= 0.672. The XMM-Newton spectrum shows a large obscuring column NH~ 1023 cm-2 corresponding to AV~ 70, in agreement with previous results based on the lower limit of the ASCA hardness ratio. The X-ray spectrum is represented by a `scattering' model with Γ~ 2.0 and where the scattered power-law normalization is a few per cent of the hard component. No FeK line is detected with a 90 per cent upper limit on its equivalent width of ~360 eV. The large discrepancy between the column density observed in X-rays and that inferred from the Balmer decrement can be explained by dust sublimation near the nucleus. Then, the X-ray and the optical obscuration come from two different regions: the X-ray close to the accretion disc, the optical at much larger > 0.25 pc scales.
- Publication:
-
Monthly Notices of the Royal Astronomical Society
- Pub Date:
- June 2003
- DOI:
- 10.1046/j.1365-8711.2003.06547.x
- arXiv:
- arXiv:astro-ph/0302375
- Bibcode:
- 2003MNRAS.342..321G
- Keywords:
-
- galaxies: active;
- quasars: general;
- X-rays: general;
- Astrophysics
- E-Print:
- To appear in MNRAS