Theory of Gamma-Ray Burst Emission in Light of BSAX Results

Abstract

We briefly discuss the theoretical implications of recent detections of gamma-ray bursts (GRBs) by BSAX. Relativistic shock wave theories of fireball expansion are challenged by the wealth of X-ray, optical and radio data obtained after the discovery of the first X-ray GRB afterglow. BSAX data contribute to address several issues concerning the initial and afterglow GRB emission. The observations also raise many questions that are still unsolved. The synchrotron shock model is in very good agreement with time-resolved broad-band spectra (2-500 keV) for the majority of GRBs detected by BSAX.Comment: 8 pages, LATEX text plus two postscript figures included. To appear in the Proceedings of the Accademia dei Lincei Symposium: "The Active X-ray Sky: Results from Beppo-SAX and Rossi-XTE", Nuclear Physics B Proceedings Supplement, eds. L. Scarsi et a