On the relation between the coronal line emission and the infrared/X ray emission in Seyfert galaxies

Abstract

The relation between the X-ray, the coronal line and the infrared (IR) emissions in a sample of the brightest known Seyfert galaxies is analysed. A close relationship between the absorption-corrected soft X-ray emission and both the mid-IR and the coronal line emission is found for the Seyfert type 2 objects in the sample. The coronal line and the X-ray emissions are both main tracers of active galactic nuclei (AGN) activity and their relationship with the mid-IR emission points to the heat of the carbuncle dust as the main energetic process associated with the AGN. On the other hand, the above relations do not seem to hold for the type 1 Seyfert discussed in the sample, at least when the comparisons are made in a flux diagram. This is partially because of the reduced number of objects of this type analysed in this work and also the fact that the measured soft X-ray emission in Seyfert 1 s is systematically larger, by at least an order of magnitude, than that in the Seyfert 2 counterparts. Finally, the hard X-ray emission in the studied sample appears unrelated to either the mid-IR or the coronal line emission.