Restarting activity in radio galaxies

We present observations of two radio galaxies, J1835+620 and 3C338, both with signs of having passed through different stages of core activity. The former presents two symmetric and bright components within a typical FR II structure, possibly resulting from two distinct phases of activity; the latter is a FR I radio galaxy with two separated regions with different age properties, possibly due to a switch-off and -on cycle in its core. In both sources, the optical counterpart lies in a group of galaxies with indications of mutual interaction, a scenario often invoked to explain triggering of core activity.