THE SUB ARCSECOND STRUCTURE OF 4C39.25

We present a new 5 GHz MERLIN image of the superluminal quasar 4C39.25 at a resolution of 70 mas. The major contribution of this new image i s that structures within the previously unresolved jet are exposed to view. The presence of a straight-line jet is now more obvious, and the structure of the source, particularly in the region where the jet ent ers the terminal hotspot, is very similar to that of larger sources. T his provides further evidence for basic similarity between sources suc h as 4C39.25 and larger sources. However, the flux in the jet is not a s strong as expected from simple versions of relativistic beaming/orie ntation unified models, and jet deceleration or bending may have to be invoked to explain the observations.