Fireballs with a Neutron Component
Abstract
Standard GRB fireballs must carry free neutrons. This crucially changes the mechanism of fireball deceleration by an external medium. As the ion fireball decelerates, the coasting neutrons form a leading front. They gradually decay, leaving behind a relativistic trail of decay products mixed with the ambient medium. The ion fireball sweeps up the trail and drives a shock wave in it. Thus, observed afterglow emission is produced in the neutron trail. The impact of neutrons turns off at 10^{17}cm from the explosion center, and here a spectral transition is expected in GRB afterglows. Absence of neutron signatures would point to absence of baryons and a dominant Poynting flux in the fireballs.
Cite
@article{arxiv.astro-ph/0302057,
title = {Fireballs with a Neutron Component},
author = {Andrei M. Beloborodov},
journal= {arXiv preprint arXiv:astro-ph/0302057},
year = {2007}
}
Comments
talk at "Gamma-Ray Bursts in the Afterglow Era: 3rd Workshop", Rome, September 2002