We report the discovery of large-scale diffuse non-thermal radio emission in PLCK G287.0+32.9 , an exceptionally hot ( T \sim 13 keV ) , massive , and luminous galaxy cluster , strongly detected by the Planck satellite in a recent , all-sky blind search for new clusters through Sunyaev–Zel ’ dovich effect .
Giant Metrewave Radio Telescope 150 MHz and Very Large Array 1.4 GHz radio data reveal a pair of giant ( > 1 Mpc ) “ arc ” shaped peripheral radio-relics ( signatures of shock waves ) of unprecedented scale ( linear separation \sim 4.4 Mpc at redshift 0.39 ) , located at distances from the cluster center which are about 0.7 and 1.3 of the cluster ’ s virial radius .
Another possible giant relic and a radio-halo is detected closer to the cluster center .
These relic sources are unique “ signposts ” of extremely energetic mergers and shocks ( both ongoing and past ) , that are assembling and heating up this very massive galaxy cluster .
They are also a probe of the filamentary cosmic-web structure beyond the cluster virial radius .
Optical imaging with the IUCAA 2m telescope and XMM-Newton X-ray data confirm a very rich galaxy cluster with a morphologically disturbed core region , suggesting a dynamically perturbed merging system .