GCN Circular 42793
Subject
EP251118a: Xinglong-2.16m optical observation
Event
Date
2025-11-22T01:34:51Z (2 days ago)
From
liuxing@nao.cas.cn
Via
Web form
X. Liu, J.J. Jin, J. Zheng, Z. Fan, D. Xu, L.B. He, J. An, S.Q. Jiang, Z.P. Zhu, J.J. Jia(NAOC), S.Y. Fu(HUST) report on behalf of a large collaboration:
We observed the field of EP251118a detected by EP/WXT (Jiang et al., GCN 42749; Shi et al., GCN 42754;) and likely GRB 251118C (Frederiks et al., GCN 42765; Wang et al., GCN 42766; Delaunay et al., GCN 42770; Woolf et al, GCN 42771) using the Xinglong-2.16m telescope equipped with the BFOSC camera. Observations started at 19:28:32 UT on 2025-11-21 (i.e., 74.77 h after the EP trigger), and 15x300 s R-band frames have been obtained.
The optical afterglow (Melasani et al., GCN 42751; An et al., GCN 42756; Belkin et al., GCN42758; Yadav et al., GCN 42760; Busmann et al., GCN 42763; Francile et al., GCN 42767; Rodríguez et al., GCN 42773; Li et al., GCN 42776; Lee et al., GCN 42780; Moskvitin et al., GCN 42785; Gupta et al., GCN42787) was cleary detected in our stacked frame with a magnitude of R = 22.1 +/- 0.1 at a mid-time of 75.28hr, calibrated with Pan-STARRS1 DR2 catalog converted using Lupton (2005) equations and not corrected for Galactic extinction.
We thank the staff at Xinglong observatory for their excellent support.