Optical/multiwavelength observations of GRB afterglows

Abstract

I review gamma-ray burst optical/multiwavelength afterglow observations since 1997, when the first counterparts to GRBs were discovered. I discuss what we have learned from multiwavelength observations of GRB afterglows in relation to the 'standard' fireball plus relativistic blast-wave models. To first order, the 'standard' model describes the afterglow observations well, but a wealth of information can be gathered from the deviations of GRB afterglow observations from this 'standard' model. These deviations provide information on the nature of the progenitor and on the physics of GRB production. In particular, I focus on the possible connection of GRBs to supernovae, on jet and circumstellar wind models, on the early-time afterglow, and on the emission from the reverse shock.