We propose proton acceleration and subsequent secondary electron production as the process resposible for the radiation emission in γ-ray bursts. In this mechanism electrons are naturally injected at energies ⪢ m ec 2 and emission above 10 MeV is expected to be one of their common features, in agreement with observations showing that most of the luminosity of these events is emitted in γ-rays. This mode of injection guarantees copious e +-e − pair production at the source and implies a relationship between the luminosity and the spectra of the bursts, the soft bursts being, in general, the most (intrinsically) luminous and hence the most distant. This, in turn, implies that bursts with soft spectra should show a galactic distribution, a fact consistent with the limited available data. It is also argued that the observed red-shift of the e +-e − annihilation feature may not always be gravitational.
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