Theoretical interpretation of the optical afterglow of GRB 030329

A distinguishing feature of GRB 030329 is the obvious rebrightening of its optical afterglow at around t ∼1.6 d. We have re-examined the event numerically in light of three candidate models. Both the density-jump model and the two-component jet model fail to produce any significant rebrightening at the right moment. The energy-injection model seems to be the most preferred choice. By engaging a sequence of energy-injection events, it provides an acceptable fit to the rebrightening at t ∼1.6 d, as well as the whole observed light curve that extends to t ∼80 d.