Prompt high-energy emission from gamma-ray bursts in the internal shock model

Understand

The prompt GRB emission is thought to arise from electrons accelerated in internal shocks propagating within a highly relativistic outflow.

• The launch of Fermi offers the prospect of observations with unprecedented sensitivity in high-energy (>100 MeV) gamma-rays.
• The aim is to explore the predictions for HE emission from internal shocks, taking into account both dynamical and radiative aspects, and to deduce how HE observations constrain the properties of the relativistic outflow.
• The emission is modeled by combining a time-dependent radiative code with a dynamical code giving the evolution of the physical conditions in the shocked regions.Synthetic lightcurves and spectra are compared to observations.