Skip to main content
Testing. You are viewing the public testing version of GCN. For the production version, go to
Introducing Einstein Probe, Astro Flavored Markdown, and Notices Schema v4.0.0. See news and announcements

GCN Circular 32692

GRB 221009A: COATLI Detection of the Afterglow
2022-10-11T16:41:09Z (2 years ago)
Alan M Watson at UNAM <>
Alan M. Watson (UNAM), Nat Butler (ASU), Simone Dichiara (PSU), Rosa L.
Becerra (UNAM), 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 bright GRB 220930A (Dichiara et al., GCN
Circ. 32632, Veres et al., GCN Circ. 32636) 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 ( from
2022-10-11 06:05 UTC to 06:39 UTC (40.2 hours after the trigger),
obtaining a total of 405 seconds of exposure in each of the g, r, i, and
z filters.

At the position of the UVOT afterglow (Dichiara et al., GCN Circ.
32632), we detect a source with the following magnitudes and 3-sigma
upper limit:

g > 20.27

r = 19.48 +/- 0.13

i = 18.49 +/- 0.07

z = 17.92 +/- 0.08

Our photometry is calibrated against the Pan-STARRS1 catalog, is on an
approximate AB system, and is 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.
Looking for U.S. government information and services? Visit