High-resolution emission-line imaging of Seyfert galaxies. I - Observations. II - Evidence for anisotropic ionizing radiation

A CCD direct imaging survey of 11 Seyfert galaxies with a mean seeing of 1.3 arcsec FWHM is presented. It is found that the major axes and spatial scales of the circumnuclear emission-line gas are very similar to those of the radio continuum sources. In the second part, this close connection between thermal and relativistic gases is examined. A scenario is proposed in which the radio jets and plasmoids shock, accelerate, and compress ambient and entrained gas, with the dominant source of ionization being the nonstellar nuclear UV continuum.