Multiwavelength Analysis of a Nearby Heavily Obscured AGN in NGC 449

TL;DR

This study conducts a comprehensive multiwavelength analysis of the heavily obscured AGN in NGC 449, revealing its intrinsic properties, accretion rate, and early co-evolution stage of the galaxy and AGN.

Contribution

It provides the first detailed broadband X-ray spectrum analysis combined with IR data to characterize the obscured AGN in NGC 449, including its intrinsic luminosity and torus properties.

Findings

Intrinsic X-ray luminosity of ~8.54×10^42 erg/s

High gas-to-dust ratio in the torus

Both host galaxy and AGN are in early co-evolution stage

Abstract

We presented the multiwavelength analysis of a heavily obscured active galactic nucleus (AGN) in NGC 449. We first constructed a broadband X-ray spectrum using the latest NuSTAR and XMM-Newton data. Its column density ($\simeq 10^{24} \rm{cm}^{-2}$) and photon index ($\Gamma\simeq 2.4$) were reliably obtained by analyzing the broadband X-ray spectrum. However, the scattering fraction and the intrinsic X-ray luminosity could not be well constrained. Combined with the information obtained from the mid-infrared (mid-IR) spectrum and spectral energy distribution (SED) fitting, we derived its intrinsic X-ray luminosity ($\simeq 8.54\times 10^{42} \ \rm{erg\ s}^{-1}$) and scattering fraction ($f_{\rm{scat}}\simeq 0.26\%$). In addition, we also derived the following results: (1). The mass accretion rate of central AGN is about $2.54 \times 10^{-2} \rm{M}_\odot\ \rm{yr}^{-1}$, and the Eddington ratio is $8.39\times 10^{-2}$; (2). The torus of this AGN has a high gas-to-dust ratio ($N_{\rm H}/A_{\rm V}=8.40\times 10^{22}\ \rm{cm}^{-2}\ \rm{mag}^{-1}$); (3). The host galaxy and the central AGN are both in the early stage of co-evolution.