Top panel: GRB duration T₉₀ vs. afterglow peak time t_p. GRBs with measured t_p are shown with red circles (green stars for LAT bursts). Upper limits on t_p are shown by the black arrows (green arrows for LAT GRBs). Bottom panel: time of the peak of the prompt emission light curve T_p,γ vs. t_p. Same symbols and colours as in the top panel. In both panels the equality is shown by the dashed line and the short GRB 090510 is shown by the green square.