A JET-CLOUD INTERACTION IN 3C-34 AT REDSHIFT Z=0.69

We report the detection of a strong jet-cloud interaction at a distanc e of 120 kpc from the nucleus of the radio galaxy 3C 34, which has red shift z = 0.69. Hubble Space Telescope images of the radio galaxy show a long narrow region of blue emission orientated along the radio axis and directed towards a radio hotspot. The William Herschel Telescope has been used to provide long-slit spectroscopic data of this object, and infrared observations made with the United Kingdom InfraRed Telesc ope have enabled its spectral energy distribution to be modelled. We p ropose that the aligned emission is associated with a region of massiv e star formation, induced by the passage of the radio jet through a ga laxy within the cluster surrounding 3C 34. A star formation rate of ab out 100M. yr(-1) is required, similar to the values necessary to produ ce the alignment effect in high-redshift radio galaxies. The consequen ces of this result for models of star formation in distant radio galax ies are discussed.