Bibcode
Tagliaferri, G.; Antonelli, L. A.; Chincarini, G.; Fernández-Soto, A.; Malesani, D.; Della Valle, M.; D'Avanzo, P.; Grazian, A.; Testa, V.; Campana, S.; Covino, S.; Fiore, F.; Stella, L.; Castro-Tirado, A. J.; Gorosabel, J.; Burrows, D. N.; Capalbi, M.; Cusumano, G.; Conciatore, M. L.; D'Elia, V.; Filliatre, P.; Fugazza, D.; Gehrels, N.; Goldoni, P.; Guetta, D.; Guziy, S.; Held, E. V.; Hurley, K.; Israel, G. L.; Jelínek, M.; Lazzati, D.; López-Echarri, A.; Melandri, A.; Mirabel, I. F.; Moles, M.; Moretti, A.; Mason, K. O.; Nousek, J.; Osborne, J.; Pellizza, L. J.; Perna, R.; Piranomonte, S.; Piro, L.; de Ugarte Postigo, A.; Romano, P.
Bibliographical reference
Astronomy and Astrophysics, Volume 443, Issue 1, November III 2005, pp.L1-L5
Advertised on:
11
2005
Journal
Citations
124
Refereed citations
96
Description
We present optical and near-infrared observations of the afterglow of
the gamma-ray burst GRB 050904. We derive a photometric redshift z =
6.3, estimated from the presence of the Lyman break falling between the
I and J filters. This is by far the most distant GRB known to date. Its
isotropic-equivalent energy is 3.4 × 1053 erg in the
rest-frame 110-1100 keV energy band. Despite the high redshift, both the
prompt and the afterglow emission are not peculiar with respect to other
GRBs. We find a break in the J-band light curve at tb = 2.6
± 1.0 d (observer frame). If we assume this is the jet break, we
derive a beaming-corrected energy E_γ ˜ (4 div 12) ×
1051 erg. This limit shows that GRB 050904 is consistent with
the Amati and Ghirlanda relations. This detection is consistent with the
expected number of GRBs at z > 6 and shows that GRBs are a powerful
tool to study the star formation history up to very high redshift.