X-Ray Radiative Transfer Calculation Based on a Physics-based Model of the Sub-parsec-scale Gases around an Active Galactic Nucleus and Its Application to NGC 3783

Abstract

Although the X-ray spectra of Seyfert 1 galaxies exhibit absorption lines of He-like iron and H-like iron at blue-shifted velocities of approximately $500\mathrm{km}{\mathrm{s}}^{-1}$, the physical origin of these absorption lines remains uncertain. In this study, we performed X-ray radiative transfer based on the sub-parsec-scale thermally driven outflows. The initial step involved calculating the photoionization equilibrium using the Cloudy code, which is based on three-dimensional radiative hydrodynamic simulations. Subsequently, X-ray radiative transfer was performed using the Monte Carlo simulation for astrophysics and cosmology code. Our findings indicate that when the angle of inclination ranges from $55\mathrm{degrees}$ to $65\mathrm{degrees}$, the transmitted component of the X-ray spectrum displays absorption lines of He-like and H-like iron, exhibiting a blue shift of approximately $500\mathrm{km}{\mathrm{s}}^{-1}$. The results suggest that the absorption lines are generated by a photoionized gas within $0.005\mathrm{pc}$. Additionally, the results indicate that the scattered component of the X-ray spectrum exhibits emission lines originating from neutral iron fluorescence, He-like iron, and H-like iron. The emission lines are broadened by approximately $7000\mathrm{km}{\mathrm{s}}^{-1}$ due to the Keplerian rotation. Furthermore, the model reproduced the H-like iron and H-like iron absorption lines in NGC 3783 observed by the Chandra High Energy Transmission Grating.

19 pages, 10 figures, accepted by the ApJ