On The Evolution Of The Spectral Break In The Afterglow Of Gamma Ray   Bursts
  The temporal evolution of the spectral break in the time resolved spectral energy density of the broad band afterglow of gamma ray bursts (GRBs) 091127 and 080319B was shown recently to be inconsistent with that expected for the cooling break in the standard fireball model of GRBs. Here we show that it is, however, in good agreement with the predicted temporal evolution of the smooth injection break/bend in the cannonball model of GRBs. 
Shlomo Dado and Arnon Dar
astro-ph.HE