2003/01/31 by Yong-Feng Huang, Y. F. Huang, K. S. Cheng · 2 citations
Physics and Astronomy · #Active galactic nucleus #Astronomy #Astrophysical Phenomena and Observations #Astrophysics #Collimated light #Electron #Flattening #Galaxy #Gamma-ray burst #Gamma-ray bursts and supernovae #Isotropy #Nuclear physics #Optics #Phase (matter) #Physics #Pulsars and Gravitational Waves Research #Relativistic beaming #Shock (circulatory) #Synchrotron #Synchrotron radiation #astro-ph
paper · pdf · doi:10.1046/j.1365-8711.2003.06430.x
published as Mon.Not.Roy.Astron.Soc.341:263-269,2003 · MNRAS in press (originally submitted in October 2002), 8 pages with 8 eps figures embedded, references updated
arxiv created 2003/02/23 · openalex publication_date 2003/05/01 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
Gamma-ray burst remnants become trans-relativistic typically in days to tens of days, and they enter the deep Newtonian phase in tens of days to months, during which the majority of shock-accelerated electrons will no longer be highly relativistic. However, a small portion of electrons are still accelerated to ultra-relativistic speeds and are capable of emitting synchrotron radiation. The distribution function for electrons is re-derived here so that synchrotron emission from these relativistic electrons can be calculated. Based on the revised model, optical afterglows from both isotropic fireballs and highly collimated jets are studied numerically, and compared to analytical results. In the beamed cases, it is found that, in addition to the steepening due to the edge effect and the lateral expansion effect, the light curves are universally characterized by a flattening during the deep Newtonian phase.