TITLE: GCN CIRCULAR NUMBER: 39528 SUBJECT: EP250223a: J band upper limit by SYSU 80cm telescope DATE: 25/02/28 11:41:02 GMT FROM: Wei-Sen Huang at SYSU huangws5@mail2.sysu.edu.cn
Wei-Sen Huang, Jin-Ji Li, Chun Chen, Zhong-Nan Dong, Jia-Qi Lin, Pu Lin, Hao-Nan Yang, Yan Yu, Hao-Ran Zhang, Si-Yuan Zhu, P H Thomas Tam, Rong-Feng Shen, Bin Ma (Sun Yat-sen University) report on behalf of the SYSU 80cm telescope team:
We observed the field of EP250223a (Lian et al., GCN 39429; Kennea et al., GCN 39437; Wang et al., GCN 39448) using the Sun Yat-sen University 80cm infrared telescope in J band. The calculated position is R.A. = 98.2712, DEC = -22.4449 (J2000), from EP/FXT observation. Our first observations began at 2025-02-24 12:10:00 UTC, 21.09 hours after the EP trigger, with 180 x 20 s exposures. The second observations began at 2025-02-25 12:54:00 UTC, 45.82 hours after the EP trigger, with 90 x 20 s exposures.
We do not detect any counterpart in the stacked images at the position of the optical afterglow(Lipunov et al., GCN 39434; Hauptmann et al., GCN 39436; Levan et al., GCN 39438; Wu et al., GCN 39439; Pérez-Fournon et al., GCN 39440; Izzo et al., GCN 39441; Xin et al., GCN 39445; Guo et al., GCN 39447; An et al., GCN 39449; Ducoin et al., GCN 39453; O’Neill et al., GCN 39455; Aryan et al., GCN 39464; Saikia et al., GCN 39472; Wang et al., GCN 39476; Mazaeva et al., GCN39496), down to a 5-sigma depth of J~17.2 Vega magnitudes on 2025-02-24 and J~17.0 Vega magnitudes on 2025-02-25.
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