TITLE:   GCN CIRCULAR
NUMBER:  42914
SUBJECT: EP251130a: JinShan optical observations
DATE:    25/12/01 06:43:09 GMT
FROM:    L. B. He at NAOC <helb@bao.ac.cn>

L.B. He, J. An, S.Q. Jiang, X. Liu, Z.P. Zhu, D. Xu (NAOC), S.Y. Fu, A.D. Zhu, L. Lei, H.Z. Wu (HUST), J.Z. Liu (XAO) report on behalf of a large collaboration:

We observed the field of EP251130a (Wu et al., GCN 42903) using the 100B telescope of the JinShan project, located at Altay, Xinjiang, China. Obervations started at 2025-11-30 14:13:38 UT, i. e. 3.1 hrs post-burst, and a series of frames in g, r and i bands were obtained.

The previously reported optical counterpart candidate (Dornic et al., GCN 42904) was detected in our stacked i-band frame with a magnitude i = 20.60 +/- 0.18 at a mid-time 4.67 hrs post-burst. The magnitude was callibrated with nearby PanSTARRS1 dr2 catalog and without the Galactic extinction correction.

We acknowledge the excellent support from T.Q. Chen and J.F. Zhang for enabling these observations.