Spectral analysis of 35 GRBs/XRFs observed with HETE-2/FREGATE

C. Barraud (1) , J-F. Olive (1) , J. P. Lestrade (1) , J-L. Atteia (1) , K. Hurley , G. Ricker , D. Q. Lamb , N. Kawai , M. Boer (2) , J-P. Dezalay (2) , G. Pizzichini , R. Vanderspek , G. Crew , J. Doty , G. Monelly , J. Villasenor , N. Butler , A. Levine , A. Yoshida , Y. Shirasaki , T. Sakamoto , T. Tamagawa , K. Torii , M. Matsuoka , E. E. Fenimore , M. Galassi , T. Tavenner , T. Q. Donaghy , C. Graziani , J. G. Jernigan

1 UMS 831 - Services communs OMP
2 CESR - Centre d'étude spatiale des rayonnements

We present a spectral analysis of 35 GRBs detected with the HETE-2 gamma-ray detectors (the FREGATE instrument) in the energy range 7-400 keV. The GRB sample analyzed is made of GRBs localized with the Wide Field X-ray Monitor onboard HETE-2 or with the GRB Interplanetary Network. We derive the spectral parameters of the time-integrated spectra, and present the distribution of the low-energy photon index, alpha, and of the peak energy, e_peak . We then discuss the existence and nature of the recently discovered X-Ray Flashes and their relationship with classical GRBs.

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

C. Barraud, J-F. Olive, J. P. Lestrade, J-L. Atteia, K. Hurley, et al.. Spectral analysis of 35 GRBs/XRFs observed with HETE-2/FREGATE. Astronomy and Astrophysics - A&A, 2003, 400, pp.1021-1030. ⟨hal-00008564⟩