2006/08/31 by Zhibin Zhang, Z. B. Zhang, G. Z. Xie +2 · 3 citations
Physics and Astronomy · #Angular momentum #Astrophysics and Cosmic Phenomena #Curvature #Electron #Falling (accident) #Gamma-ray burst #Gamma-ray bursts and supernovae #Pulsars and Gravitational Waves Research #Pulse (music) #Radiative cooling #Radiative transfer #astro-ph
paper · pdf · doi:10.1002/asna.200610666
published as Astron.Nachr.328:99-104,2007 · 6 pages; 6 figures; accepted for publication in AN with minor changes
arxiv created 2006/10/27 · openalex publication_date 2007/01/01 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05
Abstract Using a theoretical model describing pulse shapes, we have clarified the relations between the observed pulses and their corresponding timescales, such as the angular spreading time, the dynamic time as well as the cooling time. We find that the angular spreading timescale caused by curvature effect of fireball surface only contributes to the falling part of the observed pulses, while the dynamic one in the co‐moving frame of the shell merely contributes to the rising portion of pulses provided the radiative time is negligible. In addition, the pulses resulted from the pure radiative cooling time of relativistic electrons exhibit properties of fast rise and slow decay (a quasi‐FRED) profile together with smooth peaks. Besides, we interpret the phenomena of wider pulses tending to be more asymmetric to be a consequence of the difference in emission regions. Meanwhile, we find the intrinsic emission time is decided by the ratios of lorentz factors and radii of the shells between short and long bursts. Based on the analysis of asymmetry, our results suggest that the long GRB pulses may occur in the regions with larger radius, while the short bursts could locate at the smaller distance from central engine. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)