On the origin of Mega Radiohalos

We present a first attempt to investigate the origin of radio emitting electrons in the newly discovered class of Mega Radiohalos in clusters of galaxies. We study the evolution of relativistic electrons accreted by the external regions of a simulated cluster of galaxy at high resolution, including the effect of radiative losses and turbulent re-acceleration acting on relativistic electrons. We conclude that turbulent re-acceleration induced by structure formation is enough prolonged in time have the potential to produce a large reservoir of radio emitting electrons in the large regions illuminated by Mega Radiohalos observed by LOFAR.Comment: 8 pages, 6 figures, accepted A&A Letters, in pres