TITLE:   GCN CIRCULAR
NUMBER:  32860
SUBJECT: GRB 221009A: Further Gemini-South Infrared Observations
DATE:    22/10/27 01:33:55 GMT
FROM:    Brendan O'Connor at UMD  <oconnorb@umd.edu>

B. O'Connor (UMD/GWU), E. Troja (UTV/ASU), S. Dichiara (PSU),
J. Gillanders (UTV), S. B. Cenko (NASA/GSFC):

We performed target of opportunity observations of GRB 221009A
(Dichiara et al., GCN 32632, Veres et al., GCN 32636)
with the FLAMINGOS-2 spectrograph mounted on the Gemini-South
telescope. Observations began on October 26, 2022 at 23:40:44 UT
corresponding to ~17.4 d after the GRB. We obtained images in
JHK with a total exposure of 75 s in each filter.

The afterglow is clearly detected in each filter. We obtain
the following magnitudes calibrated against the 2MASS catalog:

J = 20.1 +/- 0.2 AB mag
H = 19.43 +/- 0.15 AB mag
K = 18.94 +/- 0.08 AB mag

These magnitudes are not corrected for Galactic extinction.

Further infrared observations are planned.

We acknowledge the staff of the Gemini Observatory for assistance
with these observations.