Theories of multiwavelength emission from Gamma-Ray Bursts: Prompt to afterglow

Gamma-Ray Bursts (GRBs) are powerful transient phenomena originating at cosmological distances. They outshine the entire gamma-ray sky for a brief period of time, less than 2 seconds for short-duration bursts and greater than 2 seconds for long- duration bursts. Non-Thermal radiation from particles accelerated in shocks is widely thought to be the origin of GRBs. Initial prompt radiation, which is dominated by keV-MeV gamma rays, is followed by fainter and long-lasting afterglow emission in gamma ray to radio wavelengths. In this article I will give an overview of observations and theoretical models for GRB emission from radio to very high-energy gamma rays, up to 100 GeV.