Complex diffuse emission in the $z=0.52$ cluster PLCK~G004.5-19.5
  We present radio observations of the galaxy cluster PLCK G004.5-19.5
($z=0.52$) using the Giant Metrewave Radio Telescope at 150~MHz, 325~MHz, and
610~MHz. We find an unusual arrangement of diffuse radio emission in the center
and periphery of the cluster, as well as several radio galaxies with head-tail
emission. A patch of peripheral emission resembles a radio relic, and central
emission resembles a radio halo. Reanalysis of archival XMM-Newton X-ray data
shows that PLCK G004.5-19.5 is disturbed, which has a known correlation with
the existence of radio relics and halos. Given that the number of known radio
halos and radio relics at $z>0.5$ is very limited, PLCK G004.5-19.5 is an
important addition to understanding merger-related particle acceleration at
higher redshifts.
