The Fermi observatory is advancing our knowledge of gamma-ray bursts (GRBs) through pioneering observations at high energies, covering more than seven 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 similar 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.

Fermi observations of high-energy gamma-ray emission from GRB 090217A / Ackermann, M., Ajello, M., Baldini, L., Ballet, J., Barbiellini, G., Baring, M.g., Bastieri, D., Bechtol, K., Bellazzini, R., Berenji, B., Bhat, P.n., Bissaldi, E., Blandford, R.d., Bonamente, E., Borgland, A.w., Bouvier, A., Bregeon, J., Brez, A., Briggs, M.s., Brigida, M., et al.. - In: THE ASTROPHYSICAL JOURNAL LETTERS. - ISSN 2041-8205. - STAMPA. - 717:2(2010), pp. L127-L132. [10.1088/2041-8205/717/2/L127]

Fermi observations of high-energy gamma-ray emission from GRB 090217A

BISSALDI, Elisabetta;FAVUZZI, Cecilia;GIGLIETTO, Nicola;
2010

Abstract

The Fermi observatory is advancing our knowledge of gamma-ray bursts (GRBs) through pioneering observations at high energies, covering more than seven 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 similar 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.
2010
Fermi observations of high-energy gamma-ray emission from GRB 090217A / Ackermann, M., Ajello, M., Baldini, L., Ballet, J., Barbiellini, G., Baring, M.g., Bastieri, D., Bechtol, K., Bellazzini, R., Berenji, B., Bhat, P.n., Bissaldi, E., Blandford, R.d., Bonamente, E., Borgland, A.w., Bouvier, A., Bregeon, J., Brez, A., Briggs, M.s., Brigida, M., et al.. - In: THE ASTROPHYSICAL JOURNAL LETTERS. - ISSN 2041-8205. - STAMPA. - 717:2(2010), pp. L127-L132. [10.1088/2041-8205/717/2/L127]
File in questo prodotto:
Non ci sono file associati a questo prodotto.

I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.

Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11589/9948
Citazioni
  • Scopus 32
  • ???jsp.display-item.citation.isi??? 30
social impact