151-MHz and 1.5-GHz observations of bridges in powerful extragalactic radio sources

We have observed seven 3C quasars and 12 3C radio galaxies with P 178>1027 W Hz-1sr-1 using MERLIN at 151 MHz and the VLA at 1.5 GHz. This is the first time that a significant number of objects has been mapped at such high resolution at wavelengths longer than 1 m. We detected complete bridges in 15 sources, and extended tails to the hotspots in the remaining four. The trend found previously for bridges to become more elongated in powerful sources is confirmed. As at higher frequencies, the spectra of bridges steepen away from the hotspots, with the spectral index α rising to 1.4-2.0 at the centre, between emitted frequencies of 0.3 and 3 GHz. (author)