The uncertainties in these numbers are partly due to the lack of a high-energy spectrum. The triangle with an error-bar near the center of the plot represents GRB 000301C . Triangles are bursts which have a break in their optical light curves. Contour levels scale linearly. Figure 1 shows the location of GRB 000301C in a hardness vs. duration plot.
Triangles are bursts where a break has been found in the optical light curve.
However, GRB 000301C is the only GRB with a duration consistent with the short-duration class. The expected number of identified short burst counterparts is moderated by the strong selection bias caused by the technical difficulties of rapidly obtaining precise localisations for the short GRBs.