{
  "bibcode": "2022GCN.32888....1W",
  "body": "Alan M. Watson (UNAM), Nat Butler (ASU), Rosa Becerra (UNAM), Simone\nDichiara (PSU), Tzveti Dimitrova (ASU), Oc��lotl L��pez (UNAM), Diego\nGonz��lez (UNAM), Alexander Kutyrev (GSFC), William H. Lee (UNAM), Margarita\nPereyra (UNAM), Eleonora Troja (UTV/ASU) and report:\n\nWe observed the field of the GRB 221028A (Lien et al., GCN Circ. 32874)\nwith the COATLI 50-cm telescope and HUITZI f/8 imager at the Observatorio\nAstron��mico Nacional on the Sierra de San Pedro M��rtir (\nhttp://coatli.astroscu.unam.mx) from 2022-10-29 02:13 UTC to 08:03 UTC\n(13.5 to 19.3 hours after the trigger), obtaining a total of 244 minutes of\nexposure in the r filter.\n\nAt the position of the XRT afterglow (Lien et al., GCN Circ. 32874), we do\nnot detect a source to the following 3-sigma upper limit:\n\nr > 23.4\n\nOur photometry is calibrated against the Pan-STARRS1 catalog, is on an\napproximate AB system, and is not corrected for Galactic extinction in the\ndirection of the GRB.\n\nWe thank the COATLI/HUITZI technical team and the staff of the Observatorio\nAstron��mico Nacional.",
  "circularId": 32888,
  "createdOn": 1667065408000,
  "email": "alan@astro.unam.mx",
  "subject": "GRB 221028A: COATLI Upper Limits",
  "submitter": "Alan M Watson at UNAM  <alan@astro.unam.mx>",
  "eventId": "GRB 221028A"
}