GRB 050502B optical afterglow: a jet-break at high redshift P. Afonso, J. Greiner, E. Pian, S. Covino, D. Malesani, A. Küpcü Yoldaş, T. Krühler, C. Clemens, S. McBreen, A. Rau et al. (2 more) A&A, 526 (2011) A154 Published online: 13 January 2011 DOI: 10.1051/0004-6361/200913965