{
  "subject": "GRB 250818B: TRT Optical Observation",
  "bibcode": "2025GCN.41430....1A",
  "submitter": "Zipei Zhu at NAOC <zpzhu@nao.cas.cn>",
  "body": "J. An (NAOC), K. Noysena, K. Chanchaiworawit, S. Tinyanont (NARIT), S.Y. Fu (HUST), X. Liu, Z.P. Zhu, S.Q. Jiang, L.B. He, D. Xu (NAOC) report on behalf of a large collaboration:\n\nWe carried out two-epoch observations of GRB 250818B (Wang et al., GCN 41405), using the 0.7-m telescope of the Thai Robotic Telescope network (TRT), located at Fresno, California, U.S.A (SRO) and New South Wales, Australia (SBO), respectively. And we obtained several frames in the B, V, R & I band.\n\nThe optical afterglow (Kumar et al., GCN 41406; Yao et al., GCN 41409; Zheng et al., GCN 41417; Bendtsen et al., GCN 41426; Moskvitin et al., GCN 41428) was clearly detected in our stack frames. The photometric results are presented in the following table:\n\n|mid time(h)|filter|mag(Vega)|site|\n|--|--|--|--|\n|7.75|R|19.98+/-0.06|SRO|\n|12.64|R|20.23+/-0.06|SBO|\n\nThe presented magnitudes are calibrated with Pan-STARRS DR2 catalog and not corrected for Galactic extinction.",
  "circularId": 41430,
  "eventId": "GRB 250818B",
  "submittedHow": "web",
  "format": "text/plain",
  "createdOn": 1755610187461
}