TITLE: GCN CIRCULAR NUMBER: 5989 SUBJECT: GRB 070103: TAROT Calern observatory optical observations DATE: 07/01/03 21:16:26 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 070103 detected by SWIFT (trigger 254532) with the TAROT robotic telescope (D=25cm) located at the Calern observatory, France. The observations started 23.3s after the GRB trigger (8.4s after the notice). The elevation of the field decreased from from 32 degrees above horizon and weather conditions were good. The date of trigger : t0 = 2007-01-03T20:46:39.072 The first image is trailed with a duration of 60.0s (see the description in Klotz et al., 2006, A&A 451, L39). We do not detect any OT with a limiting magnitude of: t0+23.3s to t0+83.3s : R > 15.1 The second image is 30.0s exposure in tracking mode: t0+89.7s to t0+119.7s : R > 15.9 We co-added a series of exposures: t0+89.7s to t0+229.0s : R > 16.4 Magnitudes were estimated with the nearby USNO-B1 stars and are not corrected for galactic dust extinction. N.B. Galactic coordinates are lon=101.3840 lat=-32.5757 and the galactic extinction in R band is 0.1 magnitude estimated from D. Schlegel et al. 1998ApJ...500..525S. This message may be cited.