GCN Circular 12022
Klotz A. (CESR-OMP), Gendre B. (ASDC), Boer M. (OHP-OAMP), Atteia J.L. (LATT-OMP) report: We imaged the field of GRB 110520A detected by SWIFT (trigger 453747) with the TAROT robotic telescope (D=25cm) located at the Calern observatory, France. The observations started 45s after the GRB trigger (15s after the notice). The elevation of the field decreased from 51 degrees above horizon and weather conditions were good. The date of trigger : t0 = 2011-05-20T20:28:48 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 error box with a limiting magnitude of: t0+44.9s to t0+104.9s : R > 17.3 The second image is 30.0s exposure in tracking mode: t0+119.6s to t0+149.6s : R > 18.5 We co-added a series of exposures: t0+119.6s to t0+310.9s : R > 19.0 Magnitudes were estimated with the nearby USNO-B1 stars and are not corrected for galactic dust extinction. This message may be cited.