{
  "bibcode": "2021GCN.29551....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 210222B (Gropp et al., GCN 29545) using the \nNEXT-0.6m optical telescope located at Nanshan, Xinjiang, China. \nObservations automatically started at 22:39:01 UT on 2021-02-22, i.e., \n95 s after the BAT trigger. We obtained a series of 40 s and 60 s frames \nduring the local morning twilight in the Sloan r-filter.\n\nThe previously reported optical afterglow (Gropp et al., GCN 29545; Hu \net al., GCN 29546; Strausbaugh et al., GCN 29547; Mong et al., GCN \n29548, 29550; Perley et al., GCN 29549) is detected in the stacked \nimages of the first three exposures, with r = 14.5 +/- 0.3 mag, \ncalibrated with nearby PS1 stars.",
  "circularId": 29551,
  "createdOn": 1614056758000,
  "email": "dxu@nao.cas.cn",
  "subject": "GRB 210222B: NEXT early optical afterglow observations",
  "submitter": "Dong Xu at NAOC/CAS  <dxu@nao.cas.cn>",
  "eventId": "GRB 210222B"
}