Unusual radio and optical structures in the Seyfert galaxy Markarian 6

We present 6- and 18-cm MERLIN maps of the radio structure in the Seyfert galaxy Markarian 6, along with [O III] and V-band images and a long-slit spectrum of this object. The 6-cm map combines high resolution with high sensitivity, and reveals a collimated jet on a scale of similar to 1 arcsec: one of the best examples of a radio jet yet seen in a Seyfert nucleus and remarkably similar to the structure in Markarian 3. On larger scales the 18-cm map shows features suggestive of shells or bubbles on either side of the radio jet. These are much larger than known supernova remnants and appear to be unique to this object; we discuss several possibilities for their origin. Our optical images show an elongated extended narrow-line region (ENLR) structure with knots and linear features, The ENLR is misaligned with the large-scale radio axis, and we examine the relationship between these two emission regions. Finally, we discuss the implications of the complex structures in this object for current models of Seyfert nuclei.