{
  "bibcode": "2022GCN.31853....1J",
  "body": "S.Q. Jiang, S.Y. Fu, X. Liu, D. Xu (NAOC), Z.P. Zhu (NAOC, HUST), L.P. \nXin, J.Y. Wei, G.W. Li (NAOC) report on behalf of a larger collaboration:\n\nWe observed the field of GRB 220408A detected by Swift (Caputo et al., \nGCN 31848) and Fermi (Fermi GBM team, GCN 31847) using the \nXinglong-2.16m telescope equipped with the BFOSC camera. Observations \nwere carried out starting at 12:02:32 UT on 2022-04-08 (i.e., 6.27 hr \nsince the BAT trigger), and 9x400 s frames in the R-band were obtained.\n\nThe previously reported optical counterpart (e.g., Caputo et al., GCN \n31848; Zheng & Filippenko, GCN 31850) is not detected in our stacked \nimage, down to a limiting magnitude of R ~ 20.7 (Vega) at 6.79 hr \npost-burst, calibrated with the nearby SDSS field.",
  "circularId": 31853,
  "createdOn": 1649424631000,
  "email": "dxu@nao.cas.cn",
  "subject": "GRB 220408A: Xinglong-2.16m optical upper limit",
  "submitter": "Dong Xu at NAOC/CAS  <dxu@nao.cas.cn>",
  "eventId": "GRB 220408A"
}