MG13 - Talk detail |
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Participant |
Vianello, Giacomo Vianello | |||||||
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Institution |
CIFS/SLAC - 412 matadero ave - palo alto - CA - USA | |||||||
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Session |
GRB1 |
Accepted |
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Order |
Time |
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Talk |
Oral abstract |
Title |
Fermi GRB spectra and the crisis of the Band model | |||||
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Abstract |
The Fermi/LAT gamma-ray telescope has observed 36 GRBs in 4 years of operations. Among them, the bursts with the largest number of LAT-detected photons have spectra which are not well described by the widely used Band model, independently of their energy fluences. High-energy and low-energy excesses have been detected and modeled by an additional power law component and/or by an additional thermal component; high-energy cutoffs have been observed as well. These results point towards a "Band model crisis": the unprecedented spectral coverage of Fermi (~8 keV - 100 GeV) shows the need for an improved modeling of GRB spectra, opening new exciting perspectives and challenges for interpretation and theoretical development. I will review these results, with particular regard to the connected data-analysis challenges. |
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