2003/12/19 by M. Boettcher, Markus Boettcher, Boettcher, M.
Physics and Astronomy · #Astro and Planetary Science #Astrophysics (astro-ph) #FOS: Physical sciences #Gamma-ray bursts and supernovae #astro-ph
paper · pdf · doi:10.48550/arxiv.astro-ph/0312538
18 pages, including 5 .eps files. Invited review at the Xth Marcel Grossmann Meeting on General Relativity, Rio de Janeiro, Brazil, July 2003. A few corrections w.r.t. low-energy lines, and slightly extended discussion of scattering screen scenario
openalex publication_date 2003/12/19 · arxiv created 2003/12/24 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
Absorption and reprocessing of Gamma-ray burst radiation in the environment of cosmological GRBs can be used as a powerful probe of the elusive nature of their progenitors. Although it is widely accepted that long-duration GRBs are associated with the deaths of massive stars, at least two fundamentally different scenarios concerning the final collapse are currently being considered. Delayed reddened excesses in the optical afterglows of several GRBs indicate that a supernova, possibly of Type Ic, takes place within a few days of a GRB. This supports the collapsar model, where the core of a massive star collapses promptly to a black hole. Variable X-ray features observed in the prompt and afterglow spectra of several GRBs, suggest that a highly metal enriched and dense shell of material surrounds the sources of GRBs. In some cases, evidence for expansion of these shells with velocities of a substantial fraction of the speed of light has been claimed. These observations have been interpreted as support for the supranova model, where a massive star collapses first to a supramassive neutron star, which later collapses to a black hole following loss of rotational support. In this review paper, I will present a brief overview of the current status of the observational evidence for X-ray spectral features in GRBs, and discuss their implications for both the collapsar and the supranova model.