TITLE: GCN CIRCULAR NUMBER: 43708 SUBJECT: GRB260131A/B: 3.6m DOT Optical Observations DATE: 26/02/12 07:33:33 GMT FROM: ANSHIKA GUPTA at ARIES <anshika05180@gmail.com> Anshika Gupta, Kuntal Misra, Debalina Kar, Pankaj Pawar, and Dhruv Jain (ARIES) report: We observed the field of GRB 260131A/B detected by (Fermi GBM team; GCN 43579) with the 3.6m Devasthal Optical Telescope (DOT), located at the Devasthal Observatory of the Aryabhatta Research Institute of Observational Sciences (ARIES), India. The observations were started on 2026-02-08 at 14:20:45 UT, i.e., ~8.32 days after the Fermi trigger. We have taken multiple frames with an exposure time of 300s in the R filter. We stacked the images after the alignment. We detect an optical counterpart in our stacked image at the location reported by (Gompertz et al. 2026; GCN 43586). We obtain the following preliminary magnitude in the stacked image: Date Start_UT T_start-T0(days) Filter Exp time(s) Magnitude ================================================================== 2026-02-08 14:20:45 ~8.32 R 300s*16 21.76 +/-0.03 Our detection is consistent with Gompertz et al. 2026 (GCN 43586); Lee et al. 2026 (GCN 43587); Saccardi et al. 2026 (GCN 43595); García García et al. 2026 (GCN 43599); Shi et al. 2026 (GCN 43601); Jayaraman et al. 2026 (GCN 43606); Zhu et al. 2026 (GCN 43607); Zheng et al. 2026 (GCN 43609); Adami et al. 2026 (GCN 43610); Volnova et al. 2026 (GCN 43632, 43670). The magnitude is not corrected for the Galactic extinction in the direction of the burst. Photometric calibration is performed using the standard stars from the USNO-B1.0 catalogue. View this GCN Circular online at https://gcn.nasa.gov/circulars/43708. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0LW...