TITLE:   GCN CIRCULAR
NUMBER:  37736
SUBJECT: GRB 241002B: PRIME near-infrared detection in 3rd epoch
DATE:    24/10/08 16:57:03 GMT
FROM:    Joe Durbak at UMD <gcn.joedurbak@gmail.com>

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

Following up on the previous PRIME detections (GCN 37700, GCN 37712), the transient field was observed a third time ~64 hours after the initial Fermi GBM detection (GCN 37668).

At the position of the optical counterpart reported by GOTO (GCN 37676), and the previously detected PRIME source (GCN 37700) we detect a fading uncatalogued source in H band. Using nearby VISTA Hemispherical Survey (VHS) and 2MASS stars for preliminary calibration we derive the following magnitude and limit, not corrected for Galactic extinction:  

| Filter | Mag(AB)      |
|--------|--------------|
| J      | > 21.1       |         
| H      | 20.8 +/- 0.2 |          

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, Durbak et al. 2024).

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