TITLE: GCN CIRCULAR NUMBER: 11380 SUBJECT: GRB 101024A: Zadko observatory - Gingin. Optical observations DATE: 10/10/25 09:57:20 GMT FROM: Myrtille LAAS-BOUREZ at U.Western Australia GRB 101024A: Zadko observatory - Gingin. Optical observations ------------------------------------------------------------- M. Laas-Bourez (UWA/ICRAR), A. Klotz (CESR-UPS-CNRS), D. Coward (UWA), D. Blair (UWA), M. Boer (OHP-CNRS), P. Thierry (CESR-UPS-CNRS) report: We imaged the field of GRB 101024A detected by SWIFT (trigger 437016) with the Zadko robotic telescope (D=100cm) located at the observatory - Gingin, Australia. The observations started 215s after the GRB trigger (199s after the notice). The elevation of the field increased from 27 degrees above horizon and weather conditions were good with humidity (77%). We detect a new fading source in the error box given by SWIFT We detected the candidate couterpart mentioned by De Pasquale et al. (GCNC 11370) at the following position (+/- 0.5 arcsec): RA(J2000.0) = 04h26m01s76 DEC(J2000.0) = -77d15m55s64 The first image is trailed with a duration of 30.0s (see the description in Klotz et al., 2006, A&A 451, L39). IT was taken between 214.7s - 244.7s after GRB. It will be analyzed later. Next images show the decay of the OT: OT was R=16.75 between 259s and 289s after GRB, filter C OT was R=17.07 between 305s and 335s after GRB, filter C OT was R=17.15 between 349s and 379s after GRB, filter C OT was R=17.19 between 394s and 424s after GRB, filter C Magnitudes were estimated with the star : NOMAD1 0127-0023961 and are not corrected for galactic dust extinction. N.B. Galactic coordinates are lon=290.5330 lat=-34.1439 This message may be cited.