The XMM-Newton spectrum of the high-z optically-obscured QSO RX J1343.4+0001: a classic radio quiet QSO

Abstract

We present a 30 ks XMM-Newton observation of the z = 2.35 type II radio quiet quasar RX J1343.4+0001. These data provide the first good quality X-ray spectrum for this object. We measured a continuum slope Γ = 1.85±0.10 with only an upper limit on the column density of the absorbing material of N_H^z ⪉ 10²² cm^-2 as well as an Fe Kα emission line at the 3σ confidence level. We do not find therefore a highly absorbed object nor a truly flat spectrum as suggested on the basis of previous less sensitive ROSAT and ASCA measurements. The N_H^z upper limit is fully consistent with the optical extinction 3<A_V <10 inferred from IR observations. The Fe Kα line is consistent with fluorescence from neutral iron and, noteworthy, is one of the most distant observed so far. The X-ray spectral properties of RX J1343.4+0001 agree well with the steep continuum slope (Γ ≈ 1.9) being independent of increasing redshift and luminosity as inferred by X-ray studies of large samples of RQ QSOs.

Based on observations with XMM-Newton, an ESA Science Mission with instruments and contributions directly funded by ESA Member states and the USA (NASA).