Jet reorientation in active galactic nuclei:two winged radio galaxies

Winged, or X-shaped, radio sources form a small class of morphologically peculiar extragalactic sources. We present multifrequency radio observations of two such sources. We derive maximum ages since any re-injection of fresh particles of 34 and 17 Myr for the wings of 3C 223.1 and 3C 403 respectively, based on the lack of synchrotron and inverse Compton losses. On morphological grounds we favour an explanation in terms of a fast realignment of the jet axis which occurred within a few Myr. There is no evidence for merger activity, and the host galaxies are found to reside in no more than poor cluster environments. A number of puzzling questions remain about those sources: in particular, although the black hole could realign on sufficiently short time-scales, the origin of the realignment is unknown.