# Discovery of Kiloparsec Extended Hard X-ray Continuum and Fe K alpha from the Compton Thick AGN ESO428-G014

## TL;DR

This paper reports the discovery of kiloparsec-scale diffuse hard X-ray and Fe K alpha emission in the Compton Thick AGN ESO428-G014, revealing extended structures that impact our understanding of AGN spectra.

## Contribution

It presents the first detection of extended hard X-ray and Fe K alpha emission on kiloparsec scales in a Compton Thick AGN, challenging existing models.

## Key findings

- Extended hard X-ray emission accounts for ~24% of observed 3-8 keV flux.
- The emission aligns with optical ionization cones and radio jets.
- The extended component's luminosity can be explained by scattering or molecular clouds.

## Abstract

We report the discovery of kpc-scale diffuse emission in both the hard continuum (3-6 keV) and in the Fe K alpha line in the Compton Thick (CT) Seyfert galaxy ESO428-G014. This extended hard component contains at least ~24% of the observed 3-8 keV emission, and follows the direction of the extended optical line emission (ionization cone) and radio jet. The extended hard component has ~0.5% of the intrinsic 2-10 keV luminosity within the bi-cones. A uniform scattering medium of density 1 cm-3 would produce this luminosity in a 1kpc path length in the bi-cones. Alternatively, higher column density molecular clouds in the disk of ESO428-G014 may be responsible for these components. The continuum may also be enhanced by the acceleration of charged particles in the radio jet. The steeper spectrum (Gamma ~1.7 +-0.4) of the hard continuum outside of the central 1.5" radius nuclear region suggests a contribution of scattered/fluorescent intrinsic Seyfert emission. Ultrafast nuclear outflows cannot explain the extended F K alpha emission. This discovery suggests that we may need to revise the picture at the base of our interpretation of CT AGN spectra.

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Source: https://tomesphere.com/paper/1705.10680