The "Fireshell" model in the Swift era
arXiv:0804.2816 · doi:10.1142/9789812834300_0305
Abstract
We here re-examine the validity of the constant-index power-law relation between the fireshell Lorentz gamma factor and its radial coordinate, usually adopted in the current Gamma-Ray Burst (GRB) literature on the grounds of an "ultrarelativistic" approximation. Such expressions are found to be mathematically correct but only approximately valid in a very limited range of the physical and astrophysical parameters and in an asymptotic regime which is reached only for a very short time, if any.
3 pages, 1 figure, to appear on the Proceedings of the Eleventh Marcel Grossmann Meeting, Berlin (Germany), July 2006