TITLE:   GCN CIRCULAR
NUMBER:  35708
SUBJECT: GRB 240205B: PRIME near infrared detection
DATE:    24/02/08 21:36:03 GMT
FROM:    Joe Durbak at UMD <gcn.joedurbak@gmail.com>

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

Following the FERMI GBM detection (GCN 35682), and Swift BAT detection (Moss et al. GCN 35683), we observed the transient field in the J filter with PRIME ~2 days after FERMI & Swift detection.

At the position of the optical counterpart reported by MASTER (Lipunov et al. GCN 35684) and Skynet (Dutton et al. GCN 35687), we detect an uncatalogued source in J band. Using nearby 2MASS stars for preliminary calibration we derive the following magnitudes, not corrected for Galactic extinction:  

Filter | Mag(AB)        | SNR | Seeing | Total exposure time (s) 
-------|----------------|-----|--------|-------------------------
J      | 19.65 +/- 0.15 |11.8 | 2.138” | 800


PRIME is a 1.8m telescope with 1.56 square degree FOV (0.5 arcsec/pixel) located in Sutherland, South Africa.

Further observations are planned.

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