Spectral Index of the Filaments in the Abell 523 Radio Halo

The galaxy cluster Abell 523 hosts a radio halo characterized by the presence of two filaments transversely located with respect to the cluster merger axis. In this paper, we present a spectral index image of these filaments between 1.410 and 1.782 GHz obtained with Jansky Very Large Array observations. We find a steepening of the spectral index of the filaments at frequencies greater than or similar to 1.4 GHz and an indication that bright patches are characterized by flat spectral indices. Our results are consistent with a scenario of highly-efficient turbulence induced by merger phenomena.