A Broadband X-Ray Study of a Sample of AGNs with [O iii] Measured Inclinations

Abstract

In modeling the X-ray spectra of active galactic nuclei (AGNs), the inclination angle is a parameter that can play an important role in analyzing the X-ray spectra of AGNs, but it has never been studied in detail. We present a broadband X-ray spectral analysis of the joint Nuclear Spectroscopic Telescope Array-XMM-Newton observations of 13 sources with [O iii] measured inclinations determined by Fischer et al. By freezing the inclination angles at the [O iii] measured values when modeling the observations, the spectra are well fitted, and the geometrical properties of the obscuring structure of the AGNs are slightly better constrained than those fitted when the inclination angles are left free to vary. We also test if one could freeze the inclinations at other specific angles in fitting the AGN X-ray spectra as has been commonly done in the literature. We find that one should always let the inclination angle be free to vary in modeling the X-ray spectra of AGNs, while fixing the inclination angle at [O iii] measured values and fixing the inclination angle at 60° also present correct fits of the sources in our sample. Correlations between the covering factor and the average column density of the obscuring torus with respect to the Eddington ratio are also measured, suggesting that the distribution of the material in the obscuring torus is regulated by the Eddington ratio, which is in agreement with previous studies. In addition, no geometrical correlation is found between the narrow line region of the AGN and the obscuring torus, suggesting that the geometry might be more complex than what is assumed in the simplistic unified model.