TITLE: GCN CIRCULAR NUMBER: 14777 SUBJECT: GRB 130605A: TAROT La Silla observatory optical decay DATE: 13/06/06 03:01:51 GMT FROM: Alain Klotz at IRAP-CNRS-OMP Klotz A. (IRAP-CNRS-OMP), Gendre B. (IRAP-CNRS-OMP), Boer M., Siellez K., Dereli H., Bardho O. (UNS-CNRS-OCA), Atteia J.L. (IRAP-CNRS-OMP) report: We analyzed TAROT La Silla images taken during the first hours after the GRB 130605A (Holland et al. GCNC 14773). We have a photometric follow-up of the afterglow detected by Nicuesa Guelbenzu et al. (GCNC 14774). All TAROT magnitudes are computed using the reference star NOMAD-1 0565-0204137 (RA = 134.5240528 Dec. = -33.4675072 R=12.50). The first TAROT image is trailed with a duration of 60.0s (see the description in Klotz et al., 2006, A&A 451, L39). After substraction of an overlaped star we can mesure the continuous photometry between 32.7 and 92.7s: From 32.7s to 58.5s the magnitude rises steeply until R = 14.85 From 58.5s to 92.7s the magnitude stays at about the level R = 14.9 Then the decay is recorded using the later images: Tstart Tstop Rmag 1sig (sec) (sec) 106.3 136.3 15.20 0.02 146.8 176.8 15.43 0.02 187.4 217.4 15.56 0.02 227.7 257.7 15.70 0.03 268.5 298.5 16.10 0.02 308.8 398.8 16.17 0.02 409.4 499.4 16.45 0.04 509.9 599.9 16.71 0.08 610.5 700.5 16.98 0.04 711.3 1161.3 17.88 0.07 1113.3 1203.3 18.36 0.29 1414.9 1684.9 >18.57 1515.5 4845.5 >19.41 The light curve can be fitted in three parts implying two breaks at 284s and 656s: From 76s to 284s alpha=0.65 From 284s to 656s alpha=1.3 Beyond 656s alpha=2.2 This message can be cited.