Rising optical afterglows seen by TAROT
  We present the multi-wavelength study of those gamma-ray bursts observed by TAROT. These events are characterized by the presence at early time of a rising in their optical light curves lasting a few hundred of seconds. In one case (GRB 060904B), a flare occurs at similar time in the X-ray band, while in the other cases the X-ray light curves appear smooth during the optical rise. We investigate the possible nature of this behavior and conclude th at a multi-component emission is mandatory to explain the optical-to-X-ray afterglow. 
B. Gendre (1), A. Klotz (2), G. Stratta (3), B. Preger (3), L. Piro   (4), A. Pelangeon (5), A. Galli (4), S. Cutini (3), A....