TITLE:   GCN CIRCULAR
NUMBER:  39827
SUBJECT: EP250321a: WFST optical observations
DATE:    25/03/22 02:51:05 GMT
FROM:    Jin-Jun Geng at PMO <jjgeng@pmo.ac.cn>

Jia-Zheng Zhu, Jin-Jun Geng, Ze-Lin Xu, Ning Jiang, Yan-Long Hua, Yi-Fang Liang, Ding-Fang Hu, Ji-An Jiang, Xue-Feng Wu, and Tian-Rui Sun report on behalf of the WFST team:

Following the detection of EP250321a by Einstein Probe (Hu  et al., GCN 39800), we use the Wide Field Survey Telescope (WFST Collaboration; arXiv:2306.07590) at Lenghu Astronomical Observation Base (Qinghai province, China) to search and follow up its afterglow. We observed the target position with 3x120s exposure in r-band starting from 2025-03-21T14:17:14. 

We clearly detect the optical transient (OT) reported by GCNs (Fu et al., GCN 39804; Perez-Garcia et al al., GCN 39805; Brivio et al., GCN 39807; Zhu et al., GCN 39809; Becerra et al., GCN 39810; Pérez-Fournon et al., GCN 39812; Lee et al., GCN 39815; Ghosh et al., GCN 39816; Han et al., GCN 39817; Jin et al., GCN 39822) in our image. Our preliminary results are as follows:

|Date|		|UTstart|	|t-T0 (hours)|	|Exp (sec)|	|Filter|	|Magnitude| 
----------------------------------------------------------------------------------------------      
2025-03-21	14:17:14	8.12		3 x 120 	r		22.57 +/- 0.12

We thank the WFST staff for supporting these observations.