2003/06/02 by N. Vlahakis, Nektarios Vlahakis, Fang Peng +2 · 4 citations
Physics and Astronomy · #Afterglow #Astrophysical Phenomena and Observations #Astrophysics #Classical mechanics #Decoupling (probability) #Gamma-ray burst #Gamma-ray bursts and supernovae #Lorentz factor #Lorentz transformation #Magnetic field #Magnetohydrodynamics #Mechanics #Neutron #Neutron star #Nuclear physics #Physics #Plasma #Proton #Pulsars and Gravitational Waves Research #astro-ph
paper · pdf · doi:10.1086/378580
published as Astrophys.J.594:L23-L26,2003 · 4 pages, 2 figures, submitted to ApJL
arxiv created 2003/06/02 · openalex publication_date 2003/08/04 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
We demonstrate that "hot" MHD outflows from neutron-rich black hole debris disks can significantly alleviate the baryon-loading problem in gamma-ray burst sources. We argue that the neutron-to-proton ratio in disk-fed outflows might be as high as ~30 and show, with the help of an exact semianalytic relativistic-MHD solution, that the neutrons can decouple at a Lorentz factor γ d ~ 15 even as the protons continue to accelerate to γ ∞ ~ 200 and end up acquiring ~30% of the injected energy. We clarify the crucial role that the magnetic field plays in this process and prove that purely hydrodynamic outflows must have γ d ≳ few × 10 2 . The motion of the decoupled neutrons is not collinear with that of the decoupled protons, so, in contrast to previous suggestions based on purely hydrodynamic models, the two particle groups most likely do not collide after decoupling. The decoupled neutron flow might nevertheless contribute to the observed afterglow emission.