2007/01/01 by Ehud Nakar
Physics and Astronomy · #Astrophysical Phenomena and Observations #Gamma-ray bursts and supernovae #Pulsars and Gravitational Waves Research #astro-ph
paper · pdf · doi:10.1016/j.asr.2006.12.038
published as Adv.SpaceRes.40:1224-1228,2007 · 9 pages, 2 figures; Proceedings of the 36th COSPAR Scientific Assembly, 2006, Beijing, China. Advances in Space Research in press
openalex publication_date 2007/01/01 · arxiv created 2007/03/07 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
Short-hard and long-soft gamma-ray bursts (GRBs) are two distinct phenomena, but their prompt and afterglow emission show many similarities. This suggests that two different progenitor systems lead to similar physical processes and that the prompt and afterglow observations of short-hard GRBs (SHBs) can be examined using models of long GRBs. Here, I discuss three conclusions that can be drawn from SHB observations. I show that the lower limit on the Lorentz factor of SHBs is typically ``only'' 10-50, significantly lower than that of long GRBs. SHBs with observed X-ray afterglow after 1 day are found to be roughly as efficient as long GRBs in converting the outflow energy into prompt gamma-rays. Finally, I examine the origin of SHBs with X-ray dark afterglows and find that the most plausible explanation is that these SHBs exploded in extremely low density environment (n \lesssim 10-5 cm-3)