  We compared the time (or time limit) of onset for optical afterglow emission
to the gamma-ray variability V in 76 GRBs with redshifts. In the subset (25
cases) with the rise evident in the data, we fit the shape of the onset peak as
well and compared the rising and decaying indices to V. We did not find any
evidence for any patterns between these properties and there is no statistical
support for any correlations. This indicates a lack of connection between
irregularities of the prompt gamma-ray emission and the establishment of the
afterglow phase. In the ordinary prompt internal shocks interpretation, this
would indicate a lack of relationship between V and the bulk Lorentz factor of
the event.

High Energy Astrophysical Phenomena