Torus Constraints in ANEPD-CXO245: A Compton-thick AGN with Double-Peaked Narrow Lines

TL;DR

This study constrains the torus parameters of a Compton-thick AGN with double-peaked narrow lines using multi-wavelength data, revealing a narrow torus opening and a high gas-to-dust ratio, supporting a bipolar outflow model.

Contribution

First detailed torus parameter constraints for a double-peaked narrow line Compton-thick AGN using combined X-ray and infrared data.

Findings

Line of sight crosses the torus, consistent with a type 2 AGN.

Small X-ray scattering fraction indicates narrow torus openings.

Gas-to-dust ratio exceeds Galactic value by over four times.

Abstract

We report on the torus constraints of the Compton-thick AGN with double-peaked optical narrow line region (NLR) emission lines, ANEPD-CXO245, at z=0.449 in the AKARI NEP Deep Field. The unique infrared data on this field, including those from the nine-band photometry over 2-24 $\mu$m with the AKARI Infrared Camera (IRC), and the X-ray spectrum from Chandra allow us to constrain torus parameters such as the torus optical depth, X-ray absorbing column, torus angular width ($\sigma$) and viewing angle ($i$). We analyze the X-ray spectrum as well as the UV-optical-infrared spectral energy distribution (UOI-SED) with clumpy torus models in X-ray (XCLUMPY; Tanimoto et al. 2019) and infrared (CLUMPY; Nenkova et al. 2008) respectively. From our current data, the constraints on $\sigma$--$i$ from both X-rays and UOI show that the line of sight crosses the torus as expected for a type 2 AGN. We obtain a small X-ray scattering fraction (<0.1%), which suggests narrow torus openings, giving preference to the bi-polar outflow picture of the double-peaked profile. Comparing the optical depth of the torus from the UOI-SED and the absorbing column density $N_{\rm H}$ from the X-ray spectrum, we find that the gas-to-dust ratio is $\gtrsim 4$ times larger than the Galactic value.