AN INTRINSICALLY ASYMMETRIC RADIO GALAXY-0500+630

As part of a search for high-luminosity radio galaxies with one-sided structures, the radio galaxy 0500 + 630 has been imaged with both the VLA and MERLIN and its optical spectrum determined using the Isaac New ton Telescope on La Palma. The galaxy is found to have a redshift of 0 .290 +/- 0.004. The radio observations show the source to be highly as ymmetric, with an overall structure which cannot be understood easily by ascribing it either to orientation and relativistic beaming effects or to an asymmetric distribution of gas in the central region. A comp arison of this source with objects of similar luminosity suggests that it is one of the best examples yet of a source with possibly an intri nsic asymmetry in either the collimation of its jets or the supply of energy from the central engine to opposite sides.