{
  "bibcode": "2022GCN.31998....1J",
  "body": "S.Q. Jiang (NAOC), Z.P. Zhu (NAOC,HUST), S.Y. Fu, X. Liu, D. Xu (NAOC), \nX. Gao\n(Urumqi No.1 Senior High School), J.Z. Liu (XAO) report:\n\nWe observed the field of GRB 220430A detected by Swift (Ambrosi et al., \nGCN 31972) and AGILE (Ursi et al., GCN 31975) using the HMT-0.5m \ntelescope located at Nanshan, Xinjiang, China. Observations started at \n13:58:51 UT on 2022-04-30 (i.e., 5.6 min after the BAT trigger), and \n3x20, 3x40, 4x60, 12x90 s unfiltered frames were obtained.\n\nNo optical source is detected in our stacked image at the XRT position \n(Osborne et al., GCN 31973), down to a limiting magnitude of ~19.2, \ncalibrated with the Gaia DR2 stars.",
  "circularId": 31998,
  "createdOn": 1651812763000,
  "email": "dxu@nao.cas.cn",
  "subject": "GRB 220430A: Nanshan/HMT optical upper limit",
  "submitter": "Dong Xu at NAOC/CAS  <dxu@nao.cas.cn>",
  "eventId": "GRB 220430A"
}