1999/06/17 by M. Vietri, C. Perola, L. Piro +1 · 29 citations
Engineering · Physics and Astronomy · #Astronomical Observations and Instrumentation #Astronomy #Astrophysical Phenomena and Observations #Astrophysics #Bremsstrahlung #Flux (metallurgy) #Gamma-ray burst #Gamma-ray bursts and supernovae #Line (geometry) #Line-of-sight #Observable #Optics #Photon #Physics #Torus #astro-ph
paper · pdf · doi:10.1046/j.1365-8711.1999.02918.x
published in Monthly Notices of the Royal Astronomical Society 308(4), L29-L33 (Oxford University Press) · To appear in MN Pink pages, MN-LateX, no figures
arxiv created 1999/06/17 · openalex publication_date 1999/10/01 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05
Recently, BeppoSAX and ASCA have observed an unusual resurgence of soft X-ray emission during the afterglows of GRB 970508 and 970828, together with marginal evidence for the existence of Fe lines in both objects. We consider the implications of the existence of a torus of iron-rich material surrounding the sites of gamma-ray bursts, as would be expected in the supra-nova model; in particular, we show that the fireball will quickly hit this torus, and bring it to a temperature of ≈3×107 K. Bremsstrahlung emission from the heated-up torus will cause a resurgence of the soft X-ray emission with all expected characteristics (flux level, duration and spectral hardening with time) identical to those observed during the re-burst. Also, thermal emission from the torus will account for the observed iron line flux. These events are also observable, for instance by new missions such as SWIFT, when beaming away from our line of sight makes us miss the main burst, as fast (soft) X-ray transients, with durations of ≈103 s and fluences of ≈10−7–10−4 erg cm−2. This model provides evidence in favour of the supra-nova model for gamma-ray bursts.