TITLE: GCN CIRCULAR NUMBER: 42811 SUBJECT: GRB 251122A / EP251122a: Xinglong 2.16m optical observation DATE: 25/11/23 08:45:24 GMT FROM: Yinuo Ma mayn@bao.ac.cn
Y. N. Ma, L. P. Xin, Y. L. Qiu, C. Wu, J. Wang, X. H. Han, P. P. Zhang, H. L. Li, Z. H. Yao, J. Zheng, J. Y. Wei (NAOC) report on behalf of SVOM follow-up team:
We observed the field of GRB 251122A triggered by SVOM/ECLAIRs (Lin et al., GCN 42800) and EP/WXT (Wang et al., GCN 42799; Yin et al., GCN 42808; Wang et al., GCN 42809) using the 2.16m telescope located at Xinglong observatory, China, equipped with the BFOSC camera. We obtained 7*200s frames in R-band, starting at 14:17:55 UT on 2025-11-22, about 20.8 minutes after the trigger.
The optical counterpart (Wu et al., GCN 42801; Lipunov et al., GCN 42802; Cheng et al., GCN 42803; Saccardi et al., GCN 42804; Cotter et al., GCN 42805; Li et al., GCN 42806; Sun et al., GCN 42807) was detected in the stacked image in R band. The magnitude is:
mid time (min) | exposure time (s) | band | mag | mag err ---------------|-------------------|------|--------|-------- 32.9 | 7*200 | R | 22.7 | 0.1
The photometry calibration was performed with nearby USNO-B1.0 1040-0024912 as the reference star. Our photometry was not corrected for Galactic extinction.
We thank the staff at Xinglong observatory for their excellent support.
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