TITLE: GCN CIRCULAR NUMBER: 13107 SUBJECT: GRB 120326A: TAROT Calern observatory afterglow optical detection DATE: 12/03/26 01:54:39 GMT FROM: Alain Klotz at CESR-CNRS Klotz A. (IRAP-CNRS-OMP), Gendre B. (ASDC/INAF-OAR), Boer M. (UNS-CNRS-OCA), Atteia J.L. (IRAP-CNRS-OMP) report: We imaged the field of GRB 120326A detected by SWIFT (trigger 518626) with the TAROT robotic telescope (D=25cm) located at the Calern observatory, France. The observations started 133.1s after the GRB trigger (119.3s after the notice). The elevation of the field increased from 49 degrees above horizon and weather conditions were good. We detect a new fading source in the error box given by SWIFT We detected the candidate couterpart at the XRT position mentioned by Siegel et al. (GCNC 13105) at the following position (+/- 2 arcsec): RA(J2000.0) = 18h 15m 37.06s DEC(J2000.0) = +69d 15' 35.3" OT was R~18.2 at 163s after GRB. Magnitudes were estimated with the nearby USNO-B1 stars and are not corrected for galactic dust extinction. As the afterglow was not detected by UVOT, we suggest a high redshift (but z<7) for this burst. N.B. Galactic coordinates are lon= 99.5219 lat=+28.3852 and the galactic extinction in R band is about 0.1 magnitude estimated from D. Schlegel et al. 1998ApJ...500..525S. This message may be cited.