HETE-2 Observation of two gamma-ray bursts at z > 3

J. -L. Atteia (1) , N. Kawai , R. Vanderspek , G. Pizzichini , G. R. Ricker , C. Barraud (1) , M. Boer (2) , José Braga , N. Butler , T. Cline , G. B. Crew , J. -P. Dezalay , T. Q. Donaghy , J. Doty , E. E. Fenimore , M. Galassi , C. Graziani , K. Hurley , J. G. Jernigan , D. Q. Lamb , A. Levine , R. Manchanda , F. Martel , M. Matsuoka , E. Morgan , Y. Nakagawa , J. -F. Olive , G. Prigozhin , T. Sakamoto , R. Sato , Y. Shirasaki , M. Suzuki , K. Takagishi , T. Tamagawa , K. Torii , J. Villasenor , S. E. Woosley , M. Yamauchi , A. Yoshida

1 UMS 831 - Services communs OMP
2 OHP - Observatoire de Haute-Provence

GRB 020124 and GRB 030323 constitute half the sample of gamma-ray bursts with a measured redshift greater than 3. This paper presents the temporal and spectral properties of these two gamma-ray bursts detected and localized with HETE-2. While they have nearly identical redshifts (z=3.20 for GRB 020124, and z=3.37 for GRB 030323), these two GRBs span about an order of magnitude in fluence, thus sampling distinct regions of the GRB luminosity function. The properties of these two bursts are compared with those of the bulk of the GRB population detected by HETE-2. We also discuss the energetics of GRB 020124 and GRB 030323 and show that they are compatible with the Epeak - Eiso relation discovered by Amati et al. (2002). Finally, we compute the maximum redshifts at which these bursts could have been detected by HETE-2 and we address various issues connected with the detection and localization of high-z GRBs.

Domaines: Cosmologie et astrophysique extra-galactique [astro-ph.CO]

J. -L. Atteia, N. Kawai, R. Vanderspek, G. Pizzichini, G. R. Ricker, et al.. HETE-2 Observation of two gamma-ray bursts at z > 3. The Astrophysical Journal, 2005, 626, pp.292-297. ⟨hal-00008393⟩