TITLE:   GCN CIRCULAR
NUMBER:  31882
SUBJECT: GRB 220412A: RATIR Afterglow Candidate
DATE:    22/04/12 07:25:10 GMT
FROM:    Alan M Watson at UNAM  <alan@astro.unam.mx>

Alan M. Watson (UNAM), Eleonora Troja (UTV), Nat Butler (ASU), Alexander
Kutyrev (GSFC), William H. Lee (UNAM), Michael G. Richer (UNAM), Ori Fox
(STScI), J. Xavier Prochaska (UCSC), Josh Bloom (UCB), Enrico Ramirez-Ruiz
(UCSC), Jes��s Gonz��lez (UNAM), Carlos Rom��n-Z����iga (UNAM), Harvey Moseley
(GSFC), Rosa L. Becerra (UNAM), Simone Dichiara (PSU), and Oc��lotl L��pez (UNAM)
report:

We observed the field of GRB 220412A (Klingler et al. GCN 31881) with the
Reionization and Transients Infrared Camera (RATIR) on the 1.5m Harold Johnson
Telescope at the Observatorio Astron��mico Nacional on Sierra San Pedro M��rtir
from 2022/04 12.28 to 2022/04 12.29 UTC (0.1 to 0.5 hours after the BAT
trigger), obtaining a total of 0.21 hours exposure in the r and i bands and 0.08
hours exposure in the Z, Y, J, and H bands.

We detect a bright, uncataloged source at RA = 123.967275 and declination =
30.342693 degrees (J2000), about 5.5 arcsec to the east of the current Swift XRT
SPER position. In comparison with the SDSS DR9 and 2MASS catalogs, we obtain the
following magnitudes:

   r = 19.41 +/- 0.12
   i = 19.26 +/- 0.10
   Y = 19.11 +/- 0.23

These magnitudes are in the AB system and are not corrected for Galactic
extinction in the direction of the GRB.

Despite being slightly outside the current XRT error region, we suggest that
this source is likely to be the afterglow. Observations are continuing.

We thank the staff of the Observatorio Astron��mico Nacional in San Pedro M��rtir.