# Application of Clumpy Torus Model to Broadband X-ray Spectra of Two Seyfert 1 Galaxies: IC 4329A and NGC 7469

## TL;DR

This study applies the XCLUMPY model to broadband X-ray spectra of two Seyfert 1 galaxies, revealing that their tori are less dusty than the Galactic interstellar medium, indicating a dust-rich environment in some AGNs.

## Contribution

First application of the XCLUMPY model to broadband X-ray spectra of type-1 AGNs, providing new insights into the dust and gas properties of their tori.

## Key findings

- Derived torus column densities for IC 4329A and NGC 7469.
- Found lower N_H/A_V ratios compared to the Galactic ISM.
- Indicated presence of dust-rich tori in some AGNs.

## Abstract

We apply a new X-ray clumpy torus model called XCLUMPY (Tanimoto et al. 2019), where the clump distribution is assumed to be the same as in the infrared clumpy torus model (CLUMPY) by Nenkova et al. 2008, to the broadband X-ray spectra of type-1 active galactic nuclei (AGNs) for the first time. We analyze the archival data of IC 4329A and NGC 7469 observed with NuSTAR/Suzaku and NuSTAR/XMM-Newton, respectively, whose infrared spectra were studied with CLUMPY by Ichikawa et al. 2015 and optical extinctions ($A_{\rm V}$) of the tori were estimated. We consider two models, invoking (Model 1) a relativistic reflection component from the accretion disk and (Model 2) a partial absorber. Assuming that the narrow Fe K$\alpha$ emission line at 6.4 keV originates from the torus, we separate the contribution of the torus reflection components in the total spectra. Our models yield equatorial hydrogen column densities of the tori to be $N^{\rm Equ}_{\rm H} =$ (0.53--1.43) $\times 10^{23}~\rm cm^{-2}$ and $N^{\rm Equ}_{\rm H} =$ (0.84--1.43) $\times 10^{24}~\rm cm^{-2}$, for IC 4329A and NGC 7469, respectively. We find that the $N_{\rm H}/A_{\rm V}$ ratios in the tori are by factors of 25--68 (IC 4329A) and 2.4--3.9 (NGC 7469) smaller than that in the Galactic interstellar medium (ISM). These results suggest that a non-negligible fraction of AGNs are 'dust-rich' compared with the Galactic ISM, as opposite to the general trend previously reported in many obscured AGNs.