GCN Circular 45437
J. Durbak (UMD, NASA GSFC), O. Guiffreda (UMD, NASA GSFC), F. McDaniel (UMD, NASA GSFC), R. Hamada (UOsaka), N. Passaleva (U Rome), M. El Kabir (U Rome), E. Troja (U Rome), A. S. Kutyrev (NASA/GSFC), S. B. Cenko (NASA/GSFC)
Following the SVOM (GCN 45422) detection, we observed the transient field in J and H-filters with PRIME starting ~5.5 hours and ~30 hours after SVOM detection.
Within the localization region reported by SVOM (GCN 45422) and the regions of interest reported by Einstein Probe (GCN 45436), we find no significant varying sources during the 24 hour period between follow-up observations. The limiting magnitudes (SNR>6) for each filter and epoch are given below using Vista Hemispherical Survey (VHS) and UKIRT Infrared Deep Sky Survey Large Area Survey (UKIDSS LAS) stars for calibration.
| Epoch | Filter | Mag(AB) | Calibration Survey |
|---|---|---|---|
| 1 | J | > 21.4 | VHS |
| 1 | H | > 21.2 | UKIDSS LAS |
| 2 | J | > 21.7 | VHS |
| 2 | H | > 21.3 | VHS |
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, Sumi et al. 2025).
We thank the University of Osaka observers at PRIME and the staff at SAAO for their support with these observations.