Suzaku View of the Swift/BAT Active Galactic Nuclei. V. Torus Structure of Two Luminous Radio-loud AGNs (3C 206 and PKS 0707-35)

TL;DR

This study analyzes the X-ray spectra of two luminous radio-loud AGNs, revealing that their tori are less developed than in typical Seyfert galaxies and similar to radio-quiet AGNs, with implications for understanding AGN unification models.

Contribution

First detailed broadband X-ray spectral analysis of two luminous radio-loud AGNs, quantifying torus structure and its relation to jet contribution.

Findings

Tori in luminous radio-loud AGNs are only poorly developed.

The torus reflection strength is smaller than in Seyfert galaxies.

The torus structure is similar between radio-loud and radio-quiet AGNs.

Abstract

We present the results from broad-band X-ray spectral analysis of 3C 206 and PKS 0707-35 with Suzaku and Swift/BAT, two of the most luminous unobscured and obscured radio-loud active galactic nuclei with hard X-ray luminosities of 10^{45.5} erg s^{-1} and 10^{44.9} erg s^{-1} (14--195 keV), respectively. Based on the radio core luminosity, we estimate that the X-ray spectrum of 3C 206 contains a significant (~ 60% in the 14--195 keV band) contribution from the jet, while it is negligible in PKS 0707-35. We can successfully model the spectra with the jet component (for 3C 206), the transmitted emission, and two reflection components from the torus and the accretion disk. The reflection strengths from the torus are found to be R_{torus} (= \Omega/2\pi) = 0.29 +- 0.18 and 0.41 +- 0.18 for 3C 206 and PKS 0707-35, respectively, which are smaller than those in typical Seyfert galaxies. Utilizing the torus model by Ikeda et al. (2009), we quantify the relation between the half opening angle of a torus (\theta_{oa}) and the equivalent width of an iron-K line. The observed equivalent width of 3C 206, < 71 eV, constrain the column density in the equatorial plane to N_{H}^{eq} < 10^{23} cm^{-2}, or the half opening angle to \theta_{oa} > 80^\circ if N_{H}^{eq} = 10^{24} cm^{-2} is assumed. That of PKS 0707-35, 72 +- 36 eV, is consistent with N_{H}^{eq} ~ 10^{23} cm^{-2}. Our results suggest that the tori in luminous radio-loud AGNs are only poorly developed. The trend is similar to that seen in radio-quiet AGNs, implying that the torus structure is not different between AGNs with jets and without jets.