2003/02/04 by Andrei M. Beloborodov, Beloborodov, Andrei M.
Physics and Astronomy · #Astro and Planetary Science #Astrophysics (astro-ph) #FOS: Physical sciences #Gamma-ray bursts and supernovae #Planetary Science and Exploration #astro-ph
paper · pdf · doi:10.48550/arxiv.astro-ph/0302057
talk at "Gamma-Ray Bursts in the Afterglow Era: 3rd Workshop", Rome, September 2002
arxiv created 2003/02/04 · openalex publication_date 2003/02/04 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
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 1017cm 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.