Highly luminous supernovae associated with gamma-ray bursts: I. GRB 111209A/SN 2011kl in the context of stripped-envelope and superluminous supernovae

D.A. Kann, P. Schady, F. Olivares E., S. Klose, A. Rossi, D.A. Perley, T. Krühler, J. Greiner, A. Nicuesa Guelbenzu, J. Elliott, F. Knust, R. Filgas, E. Pian, P. Mazzali, J.P.U. Fynbo, G. Leloudas, P.M.J. Afonso, C. Delvaux, J.F. Graham, A. RauS. Schmidl, S. Schulze, M. Tanga, A.C. Updike, K. Varela