A giant radio halo in the low luminosity X-ray cluster Abell 523 G. Giovannini, L. Feretti, M. Girardi, F. Govoni, M. Murgia, V. Vacca and J. Bagchi A&A, 530 (2011) L5 Published online: 03 May 2011 DOI: 10.1051/0004-6361/201116930