GCN Circular 45558

Subject

GRB 260913A: SVOM/C-GFT optical upper limit

Event

GRB 260913A

Date

2026-09-13T16:19:08Z (3 days ago)

From

SVOM_group <svomgroup@bao.ac.cn>

Via

Web form

Y.X Guan (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), X. Tian (GXU), W.-L. Zhang (PMO) report on behalf of the SVOM/C-GFT team:
 
We observed the field of GRB 260913A detected by SVOM/ ECLAIRs (Yang et al., GCN 45557Loading...
 
 ) with LATIOS on SVOM/C-GFT. Observations started at 2026-09-13T14:27:59 UTC, ~ 6.83 hr 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 SVOM/Eclairs(Yang et al., GCN 45557Loading...
 
 ) in our images. We measure the following upper limit calibrated against the Pan-STARRS DR1 catalog, and not corrected for Galactic extinction:

g > 20.3 AB (5-sigma, mid-time 7.22 hr after the trigger).
r > 20.2 AB (5-sigma, mid-time 7.48 hr after the trigger).
i > 20.1 AB (5-sigma, mid-time 6.96 hr after the trigger).


We thank the observation assistants B.-W. Li  and  H.-X. Xue 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.