TITLE: Phenomenological model of radiatively efficient relativistic shocks
ABSTRACT: We present a phenomenological model for emission from relativistic shocks. This model works best for those shocks, where dissipation of magnetic energy and radiative cooling of electrons take place on timescales shorter than the dynamical timescale.
The model predicts that the ratio of synchrotron to inverse Compton emissivities is close to unity within the emitting region and that most of the IC radiation is absorbed in front of the shock and serves as a source of energetic particles at the shock front. The balance between acceleration and absorption-injection processes fixes the typical energy of emitting electrons, which falls in the right range to explain GRB emission as synchrotron radiation from such shocks. This balancing effect also implies existence of peak energy - luminosity relation, which is similar to the Amati relation.