English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

Synchrotron radio emission is being detected from an increasing number ofgalaxy clusters. Spectral index images are a powerful tool to investigate theorigin, nature, and connection of these sources with the dynamical state of thecluster. The aim of this work is to investigate the spectral index distributionof the radio halo in the galaxy cluster A520, a complex system from an optical,radio, and X-ray point of view. We present deep Very Large Array observationsin total intensity at 325 and 1400 MHz. We produced and analyzed spectral indeximages of the radio halo in this frequency range at a resolution of 39" and 60"and looked for possible correlations with the thermal properties of thecluster. We find an integrated radio halo spectral index alpha(325-1400) ~1.12. No strong radial steepening is present and the spectral indexdistribution is intrinsically complex with fluctuations only partially due tomeasurement errors. The radio halo integrated spectral index and the clustertemperature follow the global trend observed in other galaxy clusters althougha strong point-to-point correlation between the spectral index and the thermalgas temperature has not been observed. The complex morphology in the spectralindex image of the radio halo in A520 is in agreement with the primary modelsfor radio halo formation. The flatness of the radial profile suggests that themerger is still ongoing and is uniformly and continuously (re-) acceleratingthe population of relativistic electrons responsible of the radio emission evenat large (~ 1 Mpc) distances from the cluster center.

The spectral index image of the radio halo in the cluster Abell 520 hosting a famous bow shock