Study on X-ray Spectra of Obscured AGNs based on Monte Carlo simulation - an interpretation of observed wide-band spectra

TL;DR

This paper uses Monte Carlo simulations to analyze the X-ray spectra of obscured AGNs, particularly Compton-thick types, to understand their nuclear structures and interpret observed wide-band spectra.

Contribution

It introduces a detailed simulation model of AGN spectra based on torus geometry and applies it to real data, providing insights into the structure and luminosity of obscured AGNs.

Findings

Estimated the torus column density to be ~10^24 cm^-2 for Mrk 3.

Determined the line of sight intercepts the torus near its edge.

Provided a method to estimate direct and reflected luminosities.

Abstract

Monte Carlo simulation is one of the best tools to study the complex spectra of Compton-thick AGNs and to figure out the relation between their nuclear structures and X-ray spectra. We have simulated X-ray spectra of Compton-thick AGNs obscured by an accretion torus whose structure is characterized by a half-opening angle, an inclination angle of the torus relative to the observer, and a column density along the equatorial plane. We divided the simulated spectra into three components: one direct component, an absorbed reflection component and an unabsorbed reflection component. We then deduced the dependencies of these components on the parameters describing the structure of the torus. Our simulation results were applied to fit the wide-band spectrum of the Seyfert 2 galaxy Mrk 3 obtained by $Suzaku$. The spectral analysis indicates that we observe the nucleus along a line of sight intercepting the torus near its edge, and the column density along the equatorial plane was estimated to be ~10^24 cm^-2. Using this model, we can estimate the luminosities of both the direct emission and the emission irradiating the surrounding matter. This is useful to find the time variability and time lag between the direct and reflected light.