{
  "bibcode": "2020GCN.29013....1Z",
  "body": "Z.P. Zhu (NAOC, HUST), S.Y. Fu, X. Liu, D. Xu (NAOC) report on behalf of \na larger collaboration:\n\nWe observed the field of GRB 201209A (Gropp et al., GCN 29005) using the \n2.16-m optical telescope located at Xinglong, Hebei, China, equipped \nwith the BFOSC camera. Observations started at 13:05:43 UT on \n2020-12-09, and 2x360 s, 3x600 s R-band frames were obtained.\n\nAn uncatalogued source is detected in our stacked image at coordinates\n\nR.A. (J2000) = 1:32:21.76\nDec. (J2000) = -1:45:17.13\n\nwith an uncertainty of ~0.5 arcsec, being fully consistent with the \nEnhanced XRT position (Goad et al., GCN 29009). Calibrated with nearby \nPS1 stars, the source has m(R) = 22.05 +/- 0.16 mag at a median time of \n0.321 days post-burst, whereas PS1 is deeper but no object is present at \nthe position. We thus conclude that the source is likely the optical \nafterglow of the burst.\n\nWe acknowledge excellent support from the Xinglong-2.16m observing \nstaff, in particular Aiying Zhou and Jie Zheng.",
  "circularId": 29013,
  "createdOn": 1607527493000,
  "email": "dxu@nao.cas.cn",
  "subject": "GRB 201209A: Xinglong-2.16m likely optical afterglow detection",
  "submitter": "Dong Xu at NAOC/CAS  <dxu@nao.cas.cn>",
  "eventId": "GRB 201209A"
}