TITLE: GCN CIRCULAR NUMBER: 19832 SUBJECT: GRB 160821A: TAROT Calern observatory optical detection DATE: 16/08/21 22:38:49 GMT FROM: Bruce Gendre at ASDC Gendre B. (UVI - Etelman Obs.), Klotz A., Turpin D., Atteia J.L. (CNRS-OMP-IRAP), Boer, M., Laugier, R. (CNRS-ARTEMIS) report: We imaged the field of GRB 160821A detected by SWIFT (trigger 709351) with the TAROT robotic telescope (D=25cm) located at the Calern observatory, France. The observations started 29.31min after the GRB trigger. The elevation of the field decreased from 10 degrees above horizon and weather conditions were fair. We detect a new fading source in the error box given by SWIFT (Siegel et al., GCNC 19830) at the following position (+/- 3 arcsec): RA(J2000.0) = 11h 25m 01.6s DEC(J2000.0) +42d 20' 05" OT was R~15.4 at 29.31min after GRB. Due to the brightness of the event, we encourage any follow-up. Magnitudes were estimated with the nearby USNO-B1 stars and are not corrected for galactic dust extinction. N.B. Galactic coordinates are lon=166.5065 lat=+66.7370 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.