The spectral structure and energetics of powerful radio sources
  Determining the energy spectrum of an electron population can give key
insights into the underlying physics of a radio source; however, the lack of
high resolution, broad-bandwidth observations has left many ambiguities in our
understanding of radio galaxies. The improved capabilities of telescopes such
as the JVLA and LOFAR mean that within the bandwidth of any given observation,
a detailed spectral shape can now be produced. We present recent investigations
of powerful FR-II radio galaxies at GHz and MHz frequencies and show for the
first time their small-scale spectral structure. We highlight problems in
traditional methods of analysis and demonstrate how these issues can now be
addressed. We present the latest results from low frequency studies which
suggest a potential increase in the total energy content of radio galaxy lobes
with possible implications for the energetics of the population as a whole.
