A multiwavelength map of the nuclear region of NGC 7582

Abstract

We have performed a detailed analysis of the Chandra and Hubble Space Telescope (HST) images of the Seyfert 2 galaxy NGC 7582. The dust lane, as mapped by the HST near-infrared and optical images, strongly influences the morphology of the soft X-ray emission, being spatially coincident with excess of X-ray absorption. Two `hotspots', i.e. regions where emission from higher ionization stages of O and Ne is stronger, are observed in the soft X-ray image. They can be tracers of variations of the ionization parameter, even if, at least for one of them, absorption may be the dominant effect. The positions of the `hotspots' suggest that they are not affected by the star formation regions observed with HST, being located far away from them. Therefore the starburst does not seem to play an important role in the photoionization of the soft X-ray emitting gas. The resulting picture is consistent with modified unification scenarios, where the Compton-thick torus coexists with a large-scale Compton-thin material associated with the dust lane and circumnuclear gas is photoionized by the active galactic nucleus along torus-free lines of sight.