GCN Circular 45978
Subject
GRB 261017A: Nanshan/NEXT optical upper limit
Event
Date
2026-10-18T03:53:39Z (9 hours ago)
From
syfu@nao.cas.cn
Via
Web form
S.Y. Fu, L. Lei (HUST), Z.P. Zhu, J. An, X. Liu, S.Q. Jiang, L.B. He, D. Xu (NAOC), X. Gao (Urumqi No.1 Senior High School), J.Z. Liu (XAO) report:
We observed the field of GRB 261017A detected by Fermi (Fermi GBM team, GCN 45973) and Swift (Siegel et al., GCN 45974), using the NEXT telescope located at Nanshan, Xinjiang, China. Observation started at 2026-10-17T21:45:23, i.e., 5.67 hours post-burst, and a series of r-band frames were obtained.
No uncatalogued optical transient is detected in the stacked image within the enhanced Swift-XRT error circle (Beardmore et al., GCN 45977), down to a 5-sigma limiting magnitude of r ~ 21.0, calibrated with Pan-STARRS DR2 stars in the field.
We acknowledge the excellent support from X. Gao for enabling these observations.