We report the detection of a strong jet-cloud interaction at a distance of
120 kpc from the nucleus of the radio galaxy 3C34, which has redshift 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 Telescope have enabled its spectral energy distribution
to be modelled. We propose that the aligned emission is associated with a
region of massive star-formation, induced by the passage of the radio jet
through a galaxy within the cluster surrounding 3C34. A star-formation rate of
about 100 solar masses per year is required, similar to the values necessary to
produce the alignment effect in high-redshift radio galaxies. The consequences
of this result for models of star formation in distant radio galaxies are
discussed.Comment: 12 pages including 11 figures, LaTeX. To appear in MNRA
