Variability and Unification of Blazars and Gamma Ray Bursts
  Most models for blazars and gamma-ray bursts involve relativistic plasma outflows powered by accretion processes onto black holes. The blast wave physics developed for cosmological models of GRBs is reviewed. Two points relevant for blazar modeling are made: (1) The injection of nonthermal relativistic particles in the comoving frame is simply treated though a process of energizing the plasma as it sweeps up material from the surrounding medium. (2) The primary energy source of blazar radiation derives from the bulk kinetic energy of the outflowing plasma. Thus deceleration of the plasma blast wave must be included in blazar flaring calculations, and this process will introduce temporal and spectral effects in addition to those produced by acceleration and radiative cooling. 
Charles D. Dermer (NRL) and James Chiang (NRL, JILA)