TITLE: GCN CIRCULAR NUMBER: 43537 SUBJECT: GRB 260127A: SVOM/C-GFT optical observations DATE: 26/01/28 04:44:46 GMT FROM: SVOM_group <svomgroup@bao.ac.cn> C. Wu (NAOC), Z. Kang (CHO), L.P. Xin, X.H. Han, P.P. Zhang, X.M. Lu (NAOC), Z.W. Li, Y. Lv (CHO), R.S. Zhang, Y.J. Xiao, Y.L. Qiu, J. Wang, J.S. Deng, L. Huang, J.Y. Wei (NAOC) report on behalf of the SVOM/C-GFT team: We observed the field of GRB 260127A detected by Fermi/GBM (Fermi GBM team, GCN 43528) and Swift/BAT (Klingler et al., GCN 43529) with LATIOS on SVOM/C-GFT. Observations started at 2026-01-27T19:07:40 UTC, ~76.55 min after the trigger. The optical counterpart (Saccardiet et al., GCN 43530), consistent with XRT position (Evans et al., GCN 43532; Osborne et al., GCN 43535), was detected in our stacked i-band image. The magnitude is: | Mid_t-T0(hr) | exposure time (s) | band | mag (AB) | mag_err| |--------------|-------------------|------|----------|--------| | 2.24 | 30x90s | i | 20.37 | 0.20 | Our detection is deeper than the upper limit reported by Lipunov et al. (GCN 43532). The photometry was calibrated against nearby stars from UCAC4 catalog and no correction for Galactic dust extinction was applied. We thank the observation assistants Yin-Huai Hao Chun-Lei Guo at Jilin observatory for their excellent support. The Chinese Ground Follow-up Telescope (C-GFT) for the SVOM mission is located at Jilin Station, Changchun Observatory, National Astronomical Observatories, CAS. It features two instruments: (1) CATCH at the Cassegrain focus with a 21 arcsec x 21 arcsec FOV for simultaneous g/r/i-band imaging, and (2) LATIOS, a 4k x 4k CMOS camera at the prime focus with a 1.28 deg x 1.28 deg FOV that images in g, r, and i bands via filter switching. View this GCN Circular online at https://gcn.nasa.gov/circulars/43537. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0LW...