The bumpy light-curve of the bright optical afterglow (AG) of gamma ray burst (GRB) 021004, its spectral evolution and its radio emission have been claimed to be unusual. In the Cannonball Model of GRBs that is not the case. The very early AG's shape is, as for GRB 990123, a direct tracer of the expected circumburst density profile. The unprecedented… (More)
Fig. 4.— Comparison between the ratio of the spectra (Fλ) of the optical afterglow of GRB 021004 at t1 = 0.756 days and t2 = 2.786 days after burst, normalized to ∼1 at long wavelengths, as measured by Matheson et al. (2002). The wiggles on the curve extracted from observations are artifacts of the smoothing procedure, the error in the plotted magnitude difference is estimated at 0.1 mag. The thick line in the upper panel is the prediction from Eq. (1), the one in the lower panel illustrates an abrupt injection bend at λ = λb(t2).