Discovery of a Kiloparsec Extended Hard X-Ray Continuum and Fe–Kα from the Compton Thick AGN ESO 428-G014

We report the discovery of kiloparsec-scale diffuse emission in both the hard continuum (3–6 keV) and in the Fe–Kα line in the Compton thick (CT) Seyfert galaxy ESO 428-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 1 kpc path length in the bi-cones. Alternatively, higher column density molecular clouds in the disk of ESO 428-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 (Γ ∼ 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 Fe–Kα emission. This discovery suggests that we may need to revise the picture at the base of our interpretation of CT AGN spectra.