TITLE: GCN CIRCULAR NUMBER: 7108 SUBJECT: GRB 071117: TAROT La Silla observatory optical observations DATE: 07/11/18 20:06:04 GMT FROM: Alain Klotz at CESR-CNRS Klotz, A. (CESR-OMP), Boer M. (OHP), Atteia J.L. (LATT-OMP) report: We imaged the field of GRB 071117 detected by SWIFT (trigger 296805) with the TAROT robotic telescope (D=25cm) located at the European Southern Observatory, La Silla observatory, Chile. The observations started 9.5h after the GRB trigger (GRB occured during daytime). The elevation of the field decreased from from 54 degrees above horizon and weather conditions were excellents. We co-added series of exposures taken in VRI filters from t_trig+9.5h to t_trig+11.3h. There is no OT detected in V and R bands. A source is detected in the I-band close to the limiting magnitude I~20 at a position compatible with XRT (Romano et al. GCNC 7100) and s1,s2 sources of Bloom (GCNC 7105). Due to the spatial sampling of TAROT (3.3arcsec/pixel) and to the very low signal to noise ratio we cannot discriminate between s1 and s2. The source is also present in I-band in series 11.6-13.3 h and also in the series 13.7-15.8 h but the actual processing does not allow to say if the brightness decreases or not. If we consider the I-band source TAROT is the same as the s1 source of Bloom (R=23.3), the corresponding (R-I)~3 is very high. The galactic extinction in R band is only 0.06 magnitude (estimated from D. Schlegel et al. 1998). As a consequence, we estimate that GRB 071117 is a good high redshift candidate (z>4.5). This message may be cited.