Open AccessXMM–Newton observations of an absorbed z = 0.67 QSO: no dusty torus?
Author(s) -
Georgantopoulos I.,
Georgakakis A.,
Stewart G. C.,
Akylas A.,
Boyle B. J.,
Shanks T.,
Griffiths R. E.
Publication year - 2003
Publication title -
monthly notices of the royal astronomical society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.058
H-Index - 383
eISSN - 1365-2966
pISSN - 0035-8711
DOI - 10.1046/j.1365-8711.2003.06547.x
Subject(s) - physics , torus , astrophysics , astronomy , geometry , mathematics
We present XMM–Newton observations of AX J0341.4−4453, a mildly reddened A V < 7 quasi‐stellar object (QSO) at a redshift of z = 0.672 . The XMM–Newton spectrum shows a large obscuring column N H ∼ 10 23 cm −2 corresponding to A V ∼ 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.