ASCA Observation of Unusually X-Ray-Hard Radio-Quiet QSO Kaz102

We observed the radio-quiet QSO Kaz102 (z =0 .136) with ASCA as a part of our program for a complete spectral characterization of hard X-ray selected AGNs. We found that Kaz102 shows unusual spectral properties. A simple power-law with absorption in our Galaxy gave a satisfactory description of the spectrum. However, it showed a very hard photon index of Γ ∼ 1.0 with no sign of deep absorption or a prominent spectral feature. We further explored the Compton reflection with the Fe Kα line and warm absorber models for hardening the spectra. Both gave statistically satisfactory fits. However, the Compton reflection model requires a very low metal abundance (0.03–0.07 in solar units). The warm absorber model with no direct component is preferred, and gave a very high ionization parameter of ξ ∼ 10 2.3 . If this is the case, the values of ξ, warm absorber column density, and variability over ∼ 10 yr may suggest that the warm absorber resides in the broad-line region and crosses the line of sight to the central X-ray source.