{
  "bibcode": "2021GCN.31213....1J",
  "body": "S.Q. Jiang (NAOC), Z.P. Zhu (NAOC, HUST), S.Y. Fu, X. Liu, D. Xu (NAOC), \nX. Gao (Urumqi No.1 Senior High School), J.Z. Liu (XAO) report:\n\nWe observed the field of GRB 211211A detected by Fermi (Fermi GBM team, \nGCN 31201) and Swift (D'Ai et al., GCN 31202) using the NEXT-0.6m \noptical telescope located at Nanshan, Xinjiang, China. Observations \nstarted at 23:01:09 UT on 2021-12-11, i.e., 9.85 hr after the BAT \ntrigger, and 10x200 s frames in the Sloan r-filter as well as 12x200 s \nframes in the Sloan z-filter were obtained.\n\nThe optical afterglow candidate of the GRB reported by KAIT (Zheng & \nFilippenko, GCN 31203), consistent with the enhanced Swift-XRT position \n(Beardmore et al., GCN 31205), is detected in our stacked r- and z-band \nimages. Preliminary photometry is as follows:\n\nT_mid-T0 (hr)    Mag     MagErr  Filter\n10.34               20.29    0.07        r\n10.68               19.9      0.3         z\n\nboth calibrated with nearby PS1 stars.\n\nWe note that the NEXT's r-band magnitude is comparable to that of KAIT \nin the clear band, although the time interval of the two observations is \n~10 hr.",
  "circularId": 31213,
  "createdOn": 1639309332000,
  "email": "dxu@nao.cas.cn",
  "subject": "GRB 211211A: Nanshan/NEXT optical observations",
  "submitter": "Dong Xu at NAOC/CAS  <dxu@nao.cas.cn>",
  "eventId": "GRB 211211A"
}