Theoretical interpretation of luminosity and spectral properties of GRB   031203
  The X and gamma-ray observations of the source GRB 031203 by INTEGRAL are interpreted within our theoretical model. In addition to a complete space-time parametrization of the GRB, we specifically assume that the afterglow emission originates from a thermal spectrum in the co-moving frame of the expanding baryonic matter shell. By determining the two free parameters of the model and estimating the density and filamentary structure of the ISM, we reproduce the observed luminosity in the 20-200 keV energy band. As in previous sources, the prompt radiation is shown to coincide with the peak of the afterglow and the luminosity substructure are shown to originate in the filamentary structure of the ISM. We predict a clear hard-to-soft behavior in the instantaneous spectra. The time-integrated spectrum over 20 seconds observed by INTEGRAL is well fitted. Despite this source has been considered "unusual", it appears to us a normal low energetic GRB. 
Maria Grazia Bernardini, Carlo Luciano Bianco, Pascal Chardonnet,   Federico Fraschetti, Remo Ruffini, She-Sheng Xue