Tuesday

Due to their steep spectra, low-frequency observations of FR II radio galaxies potentially provide key insights in to the morphology, energetics and underlying physics of these powerful radio sources. However, limitations imposed by the previous generation of radio interferometers at metre wavelengths have meant that this region of parameter space remains largely unexplored.

In this talk, I present the latest results using LOFAR and the VLA at frequencies between 50 and 460 MHz to investigate the dynamics, energetics and particle acceleration in FR II radio galaxies. For the first time, this allows us to undertake well resolved, detailed studies of FR IIs at low frequencies and place tight constraints on the low-energy electron distribution, magnetic field strength, and total energy content of the lobes. I discuss the impact this has on our understanding of nearby FR II radio galaxies and how an improved knowledge of their spectral structure on small spatial scales advances our understanding of the mechanisms which drive these powerful radio sources.