GCN Circular 42458
Subject
GRB 251026A: SVOM/C-GFT upper limit
Event
Date
2025-10-26T14:04:34Z (4 days ago)
From
SVOM_group <svomgroup@bao.ac.cn>
Via
Web form
Chao WU (NAOC), Zhe Kang (CHO), Liping Xin(NAOC), Xuhui Han(NAOC), Pinpin Zhang (NAOC), Xiaomeng Lu (NAOC), Zhenwei Li (CHO), You Lv (CHO), Ruosong Zhang (NAOC), Yujie Xiao(NAOC), Yulei Qiu(NAOC), Jing Wang (NAOC), Jinsong Deng(NAOC), Lei Huang(NAOC), Jianyan Wei (NAOC), J.X Cao (GXU), X. Tian (GXU) report on behalf of the SVOM/C-GFT team:
We observed the field of GRB 251026A (sb25102605) detected by SVOM/ECLAIRs (Cao et al., GCN 42454) with LATIOS on SVOM/C-GFT. Observations started at 2025-10-26T10:31:43 UTC, ~2.07 hr after the trig-ger.
A series of g, r, and i band images were obtained. No credible candidate was detected within the error box provided by SVOM/MXT (Cao et al., GCN 42454) in our stacked images. The corresponding three sigma upper limit is, mag_i=19.65 at the midpoint of the observations, T₀ + 2.15 hr.
The photometry was calibrated against nearby Pan-STARRS1 stars and no correction for Galactic dust extinction was applied. This result is consistent with Postigo et al. (GCN 42456).
We thank the observation assistants Bowen Li and Hongxu Xuan 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 arcsec x 21 arcsec 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.