TITLE:   GCN CIRCULAR
NUMBER:  37323
SUBJECT: GRB 240821A: PRIME near-infrared observations
DATE:    24/08/28 16:59:13 GMT
FROM:    Joe Durbak at UMD <gcn.joedurbak@gmail.com>

J. Durbak (UMD), E. Troja (U Rome), S. Atri(U Rome), A. S. Kutyrev (NASA/GSFC), O. Guiffreda (UMD), K. De (MIT), S. B. Cenko (NASA/GSFC)

Following the SVOM localization (GCN 37220), we observed the field of GRB 240821A in H-band with PRIME ~30 hours after the trigger.  The total exposure time was 1800s.

At the position of the candidate optical counterpart (GCN 37319), we detect a source with H~20 mag, calibrated versus nearby 2MASS stars and not corrected for Galactic extinction. 

Further observations to assess variability are planned.

PRIME is a 1.8m telescope with 1.56 square degree FOV (0.5 arcsec/pixel) located in Sutherland, South Africa at the South African Astronomical Observatory (SAAO) (Kutyrev et al. 2023, Yama et al. 2023).

We thank the Osaka University observers at PRIME and the staff at SAAO for their support with these observations.