1999/11/10 by Mario Livio, M. Livio, Eli Waxman +1 · 8 citations
Earth and Planetary Sciences · Physics and Astronomy · #Earth Systems and Cosmic Evolution #Gamma-ray bursts and supernovae #Space Science and Extraterrestrial Life #astro-ph
paper · pdf · doi:10.1086/309120
published as ApJ 538, 187 (2000) · 13 pages; Submitted to ApJ
arxiv created 1999/11/10 · openalex publication_date 2000/07/20 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/07/31
We consider models for gamma-ray bursts in which a collimated jet expands either into a homogeneous medium or into a stellar wind environment, and we calculate the expected afterglow temporal behavior. We show that (1) following a break and a faster decay afterglows should exhibit a flattening, which may be detectable in both the radio and optical bands, and (2) only observations at times much shorter than a day can clearly distinguish between a fireball interacting with a homogeneous medium and one interacting with a stellar wind. Using our results, we demonstrate that constraints can be placed on progenitor models. In particular, existing data imply that while some long-duration bursts may be produced by collapses of massive stars, it is almost certain that not all long-duration bursts are produced by such progenitors.