TITLE: GCN CIRCULAR NUMBER: 44396 SUBJECT: GRB 260421B: 3.6m DOT optical observation DATE: 26/04/23 10:00:19 GMT FROM: pawarpankaj1492@gmail.com Pankaj Pawar, Anshika Gupta, Debalina Kar, Dhruv Jain and Kuntal Misra (ARIES) report: We observed the field of GRB 260421B (Fermi GBM team, GCN 44360; Zhao et al., GCN 44362) using the 3.6m Devasthal Optical Telescope (DOT) located at Devasthal of the Aryabhatta Research Institute of observational sciencES (ARIES), India. The observations began on 2026-04-21 at 21:24:53 UT, approximately 17 hours after the trigger time. We obtained 2*300s frames in the SDSS r filter. We do not detect the optical counterpart (He et al., GCN 44363; Álvarez et al., GCN 44364; Turpin et al., GCN 44365; Wu et al., GCN 44366; Lipunov et al., GCN 44367; Schneider et al., GCN 44368; Li et al., GCN 44377; Pérez-Fournon et al., GCN 44383; Mo et al., GCN 44384; and Shi et al., GCN 44388) within the error circle, nor do we see a source at the reported location of the transient. The limiting magnitude in the stacked image is: r > 22.4 mag (AB) The magnitude is calibrated against the Pan-STARRS PS1 catalog. We thank the staff of Devasthal for their assistance during these observations. View this GCN Circular online at https://gcn.nasa.gov/circulars/44396. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0LW...