  We present here results from observations at 5.5 and 9 GHz of the Bullet
cluster 1E 0657-55.8 with the Australia Telescope Compact Array (ATCA). Our
results show detection of diffuse emission in the cluster. Our findings are
consistent with the previous observations by Shimwell et al. (2014) and
Shimwell et al. (2015) at 1.1-3.1 GHz. Morphology of diffuse structures (relic
regions A and B and the radio halo) are consistent with those reported by the
previous study. Our results indicate steepening in the spectral index at higher
frequencies (at and greater than 5.0 GHz) for region A. The spectrum can be fit
well by a broken power law. We discuss the possibility of a few recent
theoretical models explaining this break in the power law spectrum, and find
that a modified Diffusive Shock Acceleration (DSA) model or a turbulent
reacceleration model may be relevant. Deep radio observations at high
frequencies (at and greater than 5 GHz) are required for a detailed comparison
with this model.
