GRB 070311: A COMMON ORIGIN FOR THE PROMPT AND AFTERGLOW EMISSION

GRB 070311 was a long burst that triggered INTEGRAL. We present prompt gamma-ray, early NIR/optical, late optical and X-ray data on this burst and its afterglow. Interestingly, the H-band light curve acquired with REM exhibits two pulses at 80 and 140 s after the peak of the gamma-ray burst, with possible evidence for a contemporaneous faint gamma-ray tail. The late optical and X-ray afterglow underwent a rebrightening between 3 x 10(4) and 2 x 10(5) s after the burst with energy comparable with that of the prompt emission extrapolated in the X-ray band. After fitting the early gamma-ray and optical light curves, we modelled the time profile of the late rebrightening as the time-rescaled version of the prompt gamma-ray pulse over an underlying power law. This result supports a common origin for both prompt and late X-ray/optical afterglow rebrightening of GRB 070311 within the external shock scenario.