{
  "bibcode": "2021GCN.29235....1X",
  "body": "L. P. Xin(NAOC),  J. Wang(GXU), X. H. Han(NAOC), J. Y. Wei(NAOC), \nG. W. LI(NAOC),  L. H. Li(NAOC), C. Wu(NAOC),  X. G. Wang(GXU), \nE. W. Liang (GXU), R. S. Zhang(NAOC), Y. L. Qiu(NAOC), \nand J. S. Deng(NAOC) report: \n\nWe began to observe GRB 210104A (Troja et al., GCN 29233)\nwith Xinglong GWAC-F60A telescope, China, \nat 11:28:00 (UT), 4th. Jan. 2021, about 61 sec after the burst.\n\nA series of  R, I, and B band images were obtained.\nThe optical afterglow (Troja et al., GCN 29233) \nwas clear detected in our images. \n\nThe brightness is about 14.5 mag in R band at 71 sec after the burst,\ncalibrated to the USNO B1.0 catalog.\n\nThe observations are continuing",
  "circularId": 29235,
  "createdOn": 1609761626000,
  "email": "xlp@nao.cas.cn",
  "subject": "GRB 210104A:  GWAC-F60A optical afterglow observations",
  "submitter": "Liping Xin at NAOC, SVOM  <xlp@nao.cas.cn>",
  "eventId": "GRB 210104A"
}