GCN Circular 45691
GRB 260922A: SVOM/C-GFT optical upper limit
From: SVOM_group
Issued: 2026-09-22 15:06 UTC
Type: GRB, Optical Transient

S.J. Yin(GXU), Z. Kang (CHO), C. Wu , L.P. Xin, X.H. Han, P.P. Zhang, X.M. Lu (NAOC), Z.W. Li, Y. Lv (CHO), R.S. Zhang, Y.J. Xiao, Y.L. Qiu, J. Wang, J.S. Deng, L. Huang, J.Y. Wei (NAOC) report on behalf of the SVOM/C-GFT team:

We observed the field of GRB 260922A detected by Swift/XRT (Page et al., GCN 45690) with LATIOS on SVOM/C-GFT. Observations started at 2026-09-22T10:39:18 UTC, ~ 38.6 min after the trigger.

We obtained follow-up imaging in g,r, and i bands. After preliminary analysis, no credible candidate was detected within the error box provided by Swift/XRT (Page et al., GCN 45690) in our images. We measure the following upper limit calibrated against the Pan-STARRS DR1 catalog, and not corrected for Galactic extinction:

g > 19.4 AB (3-sigma, mid-time 0.8 hr after the trigger).
r > 19.3 AB (3-sigma, mid-time 1.04 hr after the trigger).
i > 19.3 AB (3-sigma, mid-time 0.92 hr after the trigger).


We thank the observation assistants Y.-H. Hao and C.-L. Guo at Jilin observatory for their excellent support.

The Chinese Ground Follow-up Telescope (C-GFT) for the SVOM mission is located at Jilin Station, Changchun Observatory, National Astronomical Observatories, CAS. It features two instruments: (1) CATCH at the Cassegrain focus with a 21 arcmin x 21 arcmin FOV for simultaneous g/r/i-band imaging, and (2) LATIOS, a 4k x 4k CMOS camera at the prime focus with a 1.28 deg x 1.28 deg FOV that images in g, r, and i bands via filter switching.

Filter: gamma-ray bursts are posted only if in the top 10% of the past year's — by fluence (total energy received per cm², from Fermi GBM, Konus-Wind, GECAM and similar circulars; now ≥ 3.9×10^-5 erg/cm²) or by the number of GCN Circulars about the burst (now ≥ 14). Thresholds are recalculated monthly.
Relayed automatically from NASA's General Coordinates Network.