1996A&A...305..727H

The conical structure of nuclear high excitation gas in the Seyfert 1.5 galaxy NGC 1365 has been studied in terms of morphology and kinematics. The observations considered are narrow-band images in [OIII]λ5007 and in Hα (Joersaeter et al. 1995), as well as long slit spectra obtained at different orientations over the galaxy (P.O. Lindblad et al. 1995). The [OIII]λ5007 image shows a conical structure that does not have any resemblance with the Hα image. While the Hα, Hβ, [NII]λ6548,λ6583 and [SII]λ6716,λ6731 spectral lines show the galactic rotation, perturbed by the bar, of the disc gas, the [OIII]λ4959,λ5007 and [NeIII]λ3869 lines establish a completely different velocity field. Sometimes the emission lines are split. We present a kinematic model of this peculiar velocity field in terms of an accelerated outflow in a hollow biconical structure seen projected against the emission disc, and derive geometric and kinematic parameters for the outflow. The cone axis of our model is directed closely along the rotation axis of the galaxy as a whole. The opening angle of 100degof the cone is such that the line of sight to the partially obscured Seyfert nucleus falls just inside the cone. The accelerated radial outflow has a maximum on the cone axis. A counter cone is seen partially obscured by the galactic disc. The cone is in projection aligned with a 5" long, one-sided jet-like radio structure emanating from the nucleus. Reasons for the one-sidedness of this possible jet is briefly discussed. Diagnostic line ratios for the cone fall in an interval occupied by narrow line regions in AGNs.