GCN Circular 20254
Klotz A., Turpin D., Atteia J.L. (CNRS-OMP-IRAP), Boer, M., Laugier, R. (CNRS-ARTEMIS), Gendre B. (UVI - Etelman Obs.) report: We imaged the field of GRB 161214A detected by INTEGRAL (trigger 7644) with the TAROT robotic telescope (D=25cm) located at the Calern observatory, France. The observations started 24.6s after the GRB trigger (17.7s after the notice). The elevation of the field increased from 45 degrees above horizon and weather conditions were good until the end of the night. The first image is trailed with a duration of 60.0s (see the description in Klotz et al., 2006, A&A 451, L39). We detected the couterpart mentioned by Guidorzi et al. (GCNC 20252). The optical afterglow reached flux peak at t0+240s (+/- 15s). The early light curve: t0 + 25 s to t0 + 85s : Rlim = 16.6 (trailed image) t0 + 99 s to t0 + 211s : Rlim = 17.1 t0 + 222 s to t0 + 293s : R = 16.9 +/- 0.3 t0 + 304 s to t0 + 899s : R = 17.4 +/- 0.3 t0 + 910 s to t0 + 2180s : R = 18.7 +/- 0.4 Magnitudes were estimated with the nearby star NOMAD-1 0968-0244492 ra=190.7246097 dec=+06.8741839 R=15.04. Magnitudes were estimated with the nearby USNO-B1 stars and are not corrected for galactic dust extinction. N.B. Galactic coordinates are lon=296.86 lat=+69.60 and the galactic extinction in R band is about 0.1 magnitudes estimated from D. Schlegel et al. 1998ApJ...500..525S.