{
  "bibcode": "2021GCN.29252....1Z",
  "body": "Z.P. Zhu (NAOC, HUST), S.Y. Fu, X. Liu, D. Xu (NAOC), X. Gao (Urumqi \nNo.1 Senior High School), J.Z. Liu (XAO) report:\n\nWe observed the field of GRB 210104A (Troja et al., GCN 29233) using the \nNEXT-0.6m optical telescope located at Nanshan, Xinjiang, China. \nObservations started at 11:59:19 UT (i.e., 0.538 hr post-burst) on \n2021-01-04 and ended at 22:34:07 UT (i.e., 11.11 hr post-burst) on \n2021-01-04, and a series of 120 s, 200 s, 300 s Sloan r-band frames were \nobtained.\n\nPreliminary analysis of the data shows that afterglow is decaying as \nF_rband ~ t^(-\\alpha), where \\alpha = 0.73 since the very beginning of \nour observations.\n\nIf the afterglow continues to decay in this way, it would be of r ~ 20.3 \nmag at 1 day post-burst, and still bright enough for optical spectroscopy.",
  "circularId": 29252,
  "createdOn": 1609815867000,
  "email": "dxu@nao.cas.cn",
  "subject": "GRB 210104A: Nanshan/NEXT optical powerlaw decay",
  "submitter": "Dong Xu at NAOC/CAS  <dxu@nao.cas.cn>",
  "eventId": "GRB 210104A"
}