Suzaku View of the Swift/BAT Active Galactic Nuclei. III. Application of Numerical Torus Models to Two Nearly Compton Thick AGNs (NGC 612 and NGC 3081)

Abstract

The broad band spectra of two Swift/BAT AGNs obtained from Suzaku follow-up observations are studied: NGC 612 and NGC 3081. Fitting with standard models, we find that both sources show similar spectra characterized by a heavy absorption with $N_{\rm{H}} \simeq 10^{24} \ \rm{cm}^{-2}$, the fraction of scattered light is $f_{\rm{scat}} = 0.5-0.8%$, and the solid angle of the reflection component is $Ω/2π= 0.4-1.1$. To investigate the geometry of the torus, we apply numerical spectral models utilizing Monte Carlo simulations by Ikeda et al. (2009) to the Suzaku spectra. We find our data are well explained by this torus model, which has four geometrical parameters. The fit results suggest that NGC 612 has the torus half opening-angle of $\simeq 60^{\circ}-70^{\circ}$ and is observed from a nearly edge-on angle with a small amount of scattering gas, while NGC 3081 has a very small opening angle $\simeq 15^\circ$ and is observed on a face-on geometry, more like the deeply buried "new type" AGNs found by Ueda et al. (2007). We demonstrate the potential power of direct application of such numerical simulations to the high quality broad band spectra to unveil the inner structure of AGNs.