GRBs in the SWIFT and Fermi era: a new view of the prompt emission

Gamma Ray Bursts (GRBs) show evidence of different light curves, duration, afterglows, host galaxies and they explode within a wide redshift range. However, their spectral energy distributions (SEDs) appear to be very similar showing a curved shape. In 1993 Band et al. proposed a phenomenological description of the integrated spectral shape for the GRB prompt emission, the so called Band function. We present an alternative scenario to explain the curved shape of GRB SEDs: the log-parabolic model.