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Abstract: In this paper we study synchrotron and synchrotron self Compton SSCemission from internal shocks IS during the prompt and X-ray flare phases ofGamma-Ray Bursts GRBs. The aim is to test the IS model for the flare emissionand for whether GRBs can be GeV sources. We determine the parameters for whichthe IS model can account for the observed prompt and X-ray flares emission, andstudy the detectability of the high energy SSC emission by the AGILE and GLASTsatellites. We find that the detectability of the SSC emission during theprompt phase of GRBs improves for higher values of the fireball Lorentz factorand of the temporal variability. If IS is the mechanism responsible of theflare emission, and the Lorentz factor of the shells producing the flare is ofthe order of 100, the flare light curves are expected to present somesubstructures with temporal variability of 10-100 ms which are much smallerthan the average duration of flares, and similar to those observed during theprompt phase of GRBs. If one assumes lower Lorentz factors, such as 10-25, thena larger temporal variaibility of 40 s can also account for the observed flareproperties. However in this case we predict that X-ray flares do not have acounterpart at very high energies MeV-GeV. An investigation on thesubstructures of the X-ray flares light curves, and simultaneous X-ray and highenergy observations, will allow us to corroborate the hypothesis that late ISare responsible of the X-ray flares.

Autor: A. Galli 1,2,3, D. Guetta 4 1 IASF-Roma-INAF, 2 Univerisita' di Roma La Sapienza, 3 INFN-Trieste, 4 OAR-INAF


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