High-resolution radio observations of Markarian 3

We present high-sensitivity 5-GHz MERLIN and 15-GHz VLA observations of the Seyfert nucleus of Markarian 3, with angular resolutions of 40 and 250 mas respectively. Our 5-GHz MERLIN map reveals the best example to date of a pair of highly collimated radio jets in a Seyfert nucleus. The jet system is 2 arcsec ( ~ 600 pc) in extent and less than 50 mas across, and lies along P.A. 84°. Embedded in the jets are a number of compact components, and the western side terminates in a bright lobe containing a hotspot. The component at RA |(1950) 06ʰ 09ᵐ 48.ˢ423, Dec. (1950) 7^∘ 03' 10.'' 42| is unresolved and is the closest to the peak of the optical continuum emission. We therefore identify this as the radio core. Overall the source has a steep spectrum |(α ~ 1, where\, S∝ v-α)| The jet shows a slight ‘S’-shaped curvature, and this is also seen in images of the optical narrow-line emission. We discuss these observations in relation to starburst models for Seyfert activity, which we feel are difficult to reconcile with the structure of Mrk 3, the high degree of collimation being more consistent with the idea of a compact ‘central engine’.