Correlations between the temporal and spectral indices of three SGRBs, GRB 050724 (open squares), 080503 (open circles), and 100702A (crosses). The solid line is the expected function of ﹩\alpha =\beta +2﹩ for the high-latitude emission of spherically symmetric shells, and the dashed lines are the best-fit linear function for each event. For GRB 050724 and GRB 080503, both correlations cross the solid line at t ∼ 110 and t ∼ 152 s since the SGRB trigger time, respectively.