TITLE:   GCN CIRCULAR
NUMBER:  32604
SUBJECT: GRB 220930A: COATLI Upper Limits
DATE:    22/09/30 12:09:45 GMT
FROM:    Alan M Watson at UNAM  <alan@astro.unam.mx>

Alan M. Watson (UNAM), Nat Butler (ASU), Rosa L. Becerra (UNAM), Simone Dichiara (PSU), Tzveti Dimitrova (ASU), Oc��lotl L��pez (UNAM), Diego Gonz��lez (UNAM), Alexander Kutyrev (GSFC), William H. Lee (UNAM), Margarita Pereyra (UNAM), Eleonora Troja (UTV/ASU) and report:

We observed the field of the Swift/BAT GRB 220930A (Cenko, GCN Circ. 32603) with the COATLI 50-cm telescope and HUITZI f/8 imager at the Observatorio Astron��mico Nacional on the Sierra de San Pedro M��rtir (http://coatli.astroscu.unam.mx) from 2022-09-30 11:22 UTC to 11:59 UTC (10.5 to 48 minutes after the trigger), obtaining a total of 1920 seconds of exposure in the r filter.

We do not detect any uncataloged sources in the XRT error region (Cenko, GCN Circ. 32603) to a 3-sigma limit of r = 22.5.

Our photometry is calibrated against the Pan-STARRS1 catalog, are on an approximate AB system, and are not corrected for Galactic extinction in the direction of the GRB.

We thank the COATLI/HUITZI technical team and the staff of the Observatorio Astron��mico Nacional.