The narrow line active galaxies NGC 3081 and NGC 4507 : from the infrared to the UV.

Abstract

The authors present optical data on NGC 3081 and NGC 4507, acquired as part of a long slit spectroscopic search for extended ionized line emission around active galactic nuclei. For both AGNs an extended ionized region surrounding the nucleus was detected together with ionized gas in the ring of NGC 3081 and in the spiral arms of NGC 4507. The authors determine the relative contribution of the stellar population, the dust and the non-thermal source to the continuum. From the emission line intensities and their spatial gradients, they derive the characteristics of the ionized regions. They discuss the link between the inner diffuse ionized regions as well as the outer emissive regions associated to the spiral arms or to the ring, and the central non thermal source. They finally try to outline the possible physical conditions responsible for the presence of extended ionized nebulosities.