Continuous optical monitoring during the prompt emission of GRB 060111B
  We present the time-resolved optical emission of GRB 060111B during its prompt phase, measured with the TAROT robotic observatory. This is the first time that the optical emission from a gamma-ray burst has been continuously monitored with a temporal resolution of a few seconds during the prompt gamma-ray phase. The temporal evolution of the prompt optical emission at the level of several seconds is used to provide a clue to the origin of this emission. The optical emission was found to decay steadily from our first measure, 28s after the trigger, in contrast to the gamma-ray emission, which exhibits strong variability at the same time. This behaviour strongly suggests that the optical emission is due to the reverse shock. 
Alain Klotz (CESR, OHP), Bruce Gendre, Giulia Stratta (LATT, OHP),   Jean-Luc Atteia (LATT), Michel Boer (OHP), Frederic Mal...