External Shock Model for the Prompt Phase of Gamma Ray Bursts: Implications for GRB Source Models
Abstract
An external shock model for the prompt gammaray luminous phase of gammaray bursts (GRBs) is treated both analytically and numerically. A widely cited derivation claiming that an external shock model for rapidly variable GRBs must be very inefficient employs an incorrect expression for the angular timescale. Numerical results show that variable GRBs can be formed with > 10% efficiency to transform the directed kinetic energy of the relativistic fireball to gammarays. Successes of the external shock model and difficulties with an internal wind/colliding shell model are summarized. An impulsive external shock model is consistent with the supranova model.
 Publication:

GammaRay Bursts in the Afterglow Era
 Pub Date:
 June 2004
 arXiv:
 arXiv:astroph/0301340
 Bibcode:
 2004ASPC..312..301D
 Keywords:

 Astrophysics
 EPrint:
 8 pages, 2 figures, in "Gamma Ray Bursts in the afterglow era  Third Rome Workshop"