{
  "bibcode": "2022GCN.32705....1B",
  "body": "Nat Butler (ASU), Alan M. Watson (UNAM), Simone Dichiara (PSU), Rosa L.\nBecerra (UNAM), Tzveti Dimitrova (ASU), Oc��lotl L��pez (UNAM), Diego\nGonz��lez (UNAM), Alexander Kutyrev (GSFC), William H. Lee (UNAM),\nMargarita Pereyra (UNAM), Eleonora Troja (UTV/ASU) and report:\n\nWe observed the field of the bright GRB 221009A (Dichiara et al., GCN\nCirc. 32632, Veres et al., GCN Circ. 32636) with the COATLI 50-cm\ntelescope and HUITZI f/8 imager at the Observatorio Astron��mico Nacional\non the Sierra de San Pedro M��rtir (http://coatli.astroscu.unam.mx) from\n2022-10-12 04:00 UTC to 06:34 UTC (63.1 hours after the trigger),\nobtaining a total of 7560 seconds of exposure in the i filter.\n\nAt the position of the UVOT afterglow (Dichiara et al., GCN Circ.\n32632), we detect a source with the following magnitude:\n\ni = 19.10 +/- 0.02\n\nOur photometry is calibrated against the Pan-STARRS1 catalog, is on an\napproximate AB system, and is not corrected for Galactic extinction in\nthe direction of the GRB.\n\nCompared to our observations on the previous night (Watson et al., GCN\nCirc. 32692), the decay has a power-law index of 1.24 +/- 0.13.\n\nFurther observations are planned.\n\nWe thank the COATLI/HUITZI technical team and the staff of the\nObservatorio Astron��mico Nacional.",
  "circularId": 32705,
  "createdOn": 1665588205000,
  "email": "alan@astro.unam.mx",
  "subject": "GRB 221009A: COATLI Continued Monitoring of the Afterglow",
  "submitter": "Alan M Watson at UNAM  <alan@astro.unam.mx>",
  "eventId": "GRB 221009A"
}