1998/06/30 by A. Panaitescu, P. Meszaros · 1 citation
Earth and Planetary Sciences · Physics and Astronomy · #Astrophysics and Cosmic Phenomena #Axial symmetry #Collimated light #Earth Systems and Cosmic Evolution #Ejecta #Gamma-ray bursts and supernovae #Light curve #Numerical analysis #Spectral line #astro-ph
paper · pdf · doi:10.1086/308005
published as Astrophys.J. 526 (1999) 707-715 · 11 pages, 6 figures, Latex, revised version, accepted for publication by ApJ (vol 526). Includes correction to the numerical calculation of light curves from narrow jets. The section presenting numerical results was extended, showing the effect of the shell curvature and its finite thickness on the X-ray, optical, and radio afterglow light-curves
arxiv created 1999/07/23 · openalex publication_date 1999/12/01 · openalex created_date 2016/06/24 · arxiv updated 2016/08/30 · openalex updated_date 2026/08/06
We present an analytical approach to the dynamical evolution of fireballs or axisymmetric jets expanding into an external medium, with application to gamma-ray burst remnants. This method leads to numerical calculations of fireball dynamics that are computationally faster than hydrodynamic simulations. It is also a very flexible approach that can easily be extended to include more complex situations, such as a continuous injection of energy at the reverse shock and the sideways expansion in nonspherical ejecta. Some features of the numerical results for the remnant dynamical evolution are discussed and compared with the analytical results. We find that the ratio of the observer time at which the jet half-angle reaches twice its initial value to the time at which the light cone becomes wider than the jet is substantially smaller than predicted analytically. The effects that arise from the remnant's curvature and thickness further reduce this ratio, such that the afterglow light-curve break that is due to the remnant's finite angular extent overlaps the weaker break that is due to the jet's sideways expansion. An analysis of the effects of the curvature and thickness of the remnant on the afterglow light curves shows that these effects are important and should be taken into account for accurate calculations of the afterglow emission.