{
  "bibcode": "2022GCN.32532....1Z",
  "body": "Z.P. Zhu (NAOC,HUST), S.Y. Fu(NAOC), S.Q. Jiang, X. Liu, T.H. Lu, D. Xu, X. Gao (Urumqi No.1 Senior High School), J.Z. Liu (XAO) report:\n\nWe observed the field of GRB 220907A detected by Swift (Page et al., GCN 32526) and Fermi/GBM (GCN 32525) using the NEXT-0.6m telescope located at Nanshan, Xinjiang, China. We obtained a series of frames in the Sloan r-band and Sloan z-band, starting at 14:07:13 UT on 2022-09-07, i.e., 108s after the BAT trigger.\n\nNo uncatalogued optical source is detected in our stacked images at the XRT position (Page eta al., GCN32527), with upper limits as follows:\n\nT_mid-T0 (min)    Filter   Upper limit(3-sigma)\n    15.5                 r          >19.5\n    34.5                 z          >18.1\n\ncalibrated with the nearby PanSTARRS field and not corrected for Galactic extinction.",
  "circularId": 32532,
  "createdOn": 1662642299000,
  "email": "zpzhu@nao.cas.cn",
  "subject": "GRB 220907A: Nanshan/NEXT optical upper limits",
  "submitter": "Zipei Zhu at NAOC  <zpzhu@nao.cas.cn>",
  "eventId": "GRB 220907A"
}