GCN Circular 6513
Klotz, A. (CESR-OMP), Boer M. (OHP), Atteia J.L. (LATT-OMP), Gendre, B. (IASFC-INAF) report: We imaged the field of GRB 070610 detected by SWIFT (trigger 281993) with the TAROT robotic telescope (D=25cm) located at the Calern observatory, France. The observations started 36.1s after the GRB trigger (7.5s after the notice). The elevation of the field increased from from 24 degrees above horizon and weather conditions were good. The date of trigger : t0 = 2007-06-10T20:52:26.400 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 in the XRT location (Pagani et al. GCNC 6506) with a limiting magnitude of: t0+36.1s to t0+96.1s : R > 15.8 The second image is 30.0s exposure in tracking mode: t0+102.7s to t0+132.7s : R > 16.7 We co-added a series of exposures: t0+102.7s to t0+387.1s : R > 18.1 Magnitudes were estimated with the nearby USNO-B1 stars and are not corrected for galactic dust extinction. N.B. Galactic coordinates are lon= 63.2980 lat= -1.0201 and the galactic extinction in R band is 2.5 magnitudes estimated from D. Schlegel et al. 1998ApJ...500..525S. This message may be cited.