2001/04/03 by Davide Lazzati, D. Lazzati, G. Ghisellini +4 · 4 citations
Chemistry · Physics and Astronomy · #Absorption (acoustics) #Absorption edge #Astrophysical Phenomena and Observations #Astrophysics #Chemistry #Condensed matter physics #Extinction (optical mineralogy) #Flux (metallurgy) #Gamma-ray burst #Gamma-ray bursts and supernovae #Ion #Ionization #Optics #Outflow #Photoionization #Physics #RADIUS #Stars #Stellar, planetary, and galactic studies #Supernova #astro-ph
paper · pdf · doi:10.1086/321565
11 pages, 4 postscript figures, accepted for publication in ApJ
arxiv created 2001/04/03 · openalex publication_date 2001/07/20 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
The absorption feature detected in the prompt X-ray emission of GRB 990705 bears important consequences. We investigate different production mechanisms, and we conclude that the absorbing material cannot be very close to the burster and is likely to be moderately clumped. These properties challenge any model in which the burst explodes in coincidence with the core collapse of a massive rotating star. We show that the straightforward interpretation of the absorption feature as a photoionization K edge of neutral iron faces a severe problem in that it requires a huge amount of iron in the close vicinity of the burster. We then discuss an alternative scenario in which iron ions are kept in a high-ionization state by the burst flux and the absorption feature is produced by resonant scattering from hydrogen-like iron broadened by a range of outflow velocities. In this case, the physical conditions and geometry of the absorbing material are fully consistent with the presence of a young supernova remnant surrounding the burst site at a radius R ~ 10 16 cm. We finally discuss how this remnant might affect the generation of afterglows with a standard power-law flux decay.