No supernovae associated with two long-duration ¿-ray bursts
Autores:Johan P. U. Fynbo, Tobias C. Hinse, David Bersier, Páll Jakobsson, Andrew S. Fruchter, John F. Graham, Jesper Sollerman, Brian L. Jensen, Keith D. Horne, Arnaud Cassan, Suzanne Foley, Javier Gorosabel, Joshua S. Bloom, José María Castro Cerón, Lisa Kewley, Tamara M. Davis, Darach Watson, Christina C. Thöne, Uffe G. Jørgensen, Jens Hjorth