Radio Galaxies and Jet Duty Cycles

Radio-luminous active galactic nuclei, or radio galaxies, are the brightest population of objects in the extragalactic radio sky and will be seen in large numbers in essentially every SKA observation. Despite having been studied for more than seventy years, some aspects of radio galaxy physics are still poorly understood, and the SKA will shed light on this by enabling the generation of very large samples of high-resolution, sensitive, broad-band images of radio galaxies, allowing us to probe, for example, regions of particle acceleration, spectral ageing, and the magnetic field structures both internal and external to the radio lobes. A key feature of the radio galaxy population is that observations of extended sources probe the past history, and thus the duty cycles, of accretion onto the central supermassive black hole, and we discuss ways in which the SKA will improve our understanding of episodic and dying radio galaxies in particular.}