Chandra and JVLA observations of HST Frontier Fields cluster MACS
  J0717.5+3745
  To investigate the relationship between thermal and non-thermal components in
merger galaxy clusters, we present deep JVLA and Chandra observations of the
HST Frontier Fields cluster MACS J0717.5+3745. The Chandra image shows a
complex merger event, with at least four components belonging to different
merging subclusters. NW of the cluster, $\sim 0.7$ Mpc from the center, there
is a ram-pressure-stripped core that appears to have traversed the densest
parts of the cluster after entering the ICM from the direction of a galaxy
filament to the SE. We detect a density discontinuity NNE of this core which we
speculate is associated with a cold front. Our radio images reveal new details
for the complex radio relic and radio halo in this cluster. In addition, we
discover several new filamentary radio sources with sizes of 100-300 kpc. A few
of these seem to be connected to the main radio relic, while others are either
embedded within the radio halo or projected onto it. A narrow-angled-tailed
(NAT) radio galaxy, a cluster member, is located at the center of the radio
relic. The steep spectrum tails of this AGN leads into the large radio relic
where the radio spectrum flattens again. This morphological connection between
the NAT radio galaxy and relic provides evidence for re-acceleration (revival)
of fossil electrons. The presence of hot $\gtrsim 20$ keV ICM gas detected by
Chandra near the relic location provides additional support for this
re-acceleration scenario.
