TITLE: GCN CIRCULAR NUMBER: 6384 SUBJECT: GRB 070508: TAROT La Silla observatory optical observations DATE: 07/05/08 05:11:57 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 070508 detected by SWIFT (trigger 278854) with the TAROT robotic telescope (D=25cm) located at the European Southern Observatory, La Silla observatory, Chile. The observations started 829s after the GRB trigger (6s after the notice). The elevation of the field increased from from 28 degrees above horizon and weather conditions were good. The date of trigger : t0 = 2007-05-08T04:18:17.6 The first image is 90.0s exposure in tracking mode with no filter. We do not detect the UVOT candidate couterpart mentioned by Grupe et al. (GCNC 6383) with a limiting magnitude of: t0+829s to t0+919s : R > 17.8 We co-added a series of exposures with no filter: t0+829s to t0+1704s : R > 19.7 Magnitudes were estimated with the nearby USNO-B1 stars and are not corrected for galactic dust extinction. N.B. Galactic coordinates are lon=314.8792 lat=-32.4208 and the galactic extinction in R band is 0.1 magnitudes estimated from D. Schlegel et al. 1998ApJ...500..525S. This message may be cited.