Author(s): Ackermann M., Ajello M., Baldini L., Ballet J., Barbiellini G., G. Baring M., Bastieri D., Bechtol K., Bellazzini R., Berenji B., N. Bhat P., Bissaldi E., D. Blandford R., Bonamente E., W. Borgland A., Bouvier A., Bruel P., M. Casandjian J., Cohen-Tanugi J., J. Fegan S., Guillemot L., Horan D., Knodlseder J., Mehault J., Nuss E., Parent D., Pelassa V., Piron F., Tibaldo L., Vilchez N.
(Article) Published:
The Astrophysical Journal / The Astrophysical Journal Letters, vol. 717 p.L127-L132 (2010)
Links openAccess full text : 
Ref HAL: in2p3-00528823_v1
Ref Arxiv: 1007.3409
DOI: 10.1088/2041-8205/717/2/L127
Ref. & Cit.: NASA ADS
Exporter : BibTex | endNote
26 citations
Abstract:
The Fermi observatory is advancing our knowledge of Gamma-Ray Bursts (GRBs) through pioneering observations at high energies, covering more than 7 decades in energy with the two on-board detectors, the Large Area Telescope (LAT) and the Gamma-ray Burst Monitor (GBM). Here we report on the observation of the long GRB 090217A which triggered the GBM and has been detected by the LAT with a significance greater than 9 sigma. We present the GBM and LAT observations and on-ground analyses, including the time-resolved spectra and the study of the temporal profile from 8 keV up to 1 GeV. All spectra are well reproduced by a Band model. We compare these observations to the first two LAT-detected, long bursts GRB 080825C and GRB 080916C. These bursts were found to have time-dependent spectra and exhibited a delayed onset of the high-energy emission, which are not observed in the case of GRB 090217A. We discuss some theoretical implications for the high-energy emission of GRBs.
Comments: 17 pages, 4 figures. Contact Authors: Fred, Piron; Sara, Cutini; Andreas, von Kienlin