It is proposed that the gamma-ray photons that characterize the prompt
emission of Gamma-Ray Bursts are produced through the Compton drag process,
caused by the interaction of a relativistic fireball with a very dense soft
photon bath. If gamma-ray bursts are indeed associated with Supernovae, then
the exploding star can provide enough soft photons for radiative drag to be
effective. This model accounts for the basic properties of gamma-ray bursts,
i.e. the overall energetics, the peak frequency of the spectrum and the fast
variability, with an efficiency which can exceed 50%. In this scenario there is
no need for particle acceleration in relativistic collisionless shocks.
Furthermore, though Poynting flux may be important in accelerating the outflow,
no magnetic field is required in the gamma-ray production. The drag also
naturally limits the relativistic expansion of the fireball to Gamma < 10^4.Comment: Minor changes, accepted for publication in ApJ Letters, 18/11/199
