GRB 021004 is one of the best sampled gamma-ray bursts ( GRB ) to date , although the nature of its light curve is still being debated .
Here we present a large amount ( 107 ) of new optical , near-infrared ( NIR ) and millimetre observations , ranging from 2 hours to more than a year after the burst .
Fitting the multiband data to a model based on multiple energy injections suggests that at least 7 refreshed shocks took place during the evolution of the afterglow , implying a total energy release ( collimated within an angle of 1 \aas@@fstack { \circ } 8 ) of \sim 8 \times 10 ^ { 51 } erg .
Analysis of the late photometry reveals that the GRB 021004 host is a low extinction ( A _ { V } \sim 0.1 ) starburst galaxy with M _ { B } \simeq - 22.0 .