GCN Circular 46058
Subject
GRB 261026A: EP-FXT follow-up observation
Event
Date
2026-10-27T10:57:10Z (5 days ago)
From
EP Team at NAOC/CAS <ep_ta@bao.ac.cn>
Via
Web form
S. Q. Jiang, J. W. Hu, C. L. Guo, B. B. Zhang, K. Ao (NAO, CAS), A. D. Zhu (HUST), Z. X. Ling (NAO, CAS) on behalf of the Einstein Probe (EP) team:
EP-FXT performed a follow-up observation of GRB 261026A, detected by SVOM/ECLAIRs (Goto et al., GCN 46030), which was also observed in optical by SVOM/COLIBRÍ (Dornic et al., GCN 46033), KAIT (Zheng et al., GCN 46034), SVOM/VT (Wu et al., GCN 46035; Li et al., GCN 46046), WINTER ( Mohan et al., GCN 46041), SYSU 80cm telescope (Shi et al., GCN 46047), ULL-ASTRO-MASTER (Morín-González et al., GCN 46048), Ondrejov D50 (Novotny et al., GCN 46049), OHP/T120 (Coyo et al., GCN 46054) and 60cm Panzhihua Telescope (Zhao et al., GCN 46056). The observation started at 2026-10-26 06:59:08 (UTC), about 49.52 mins after the SVOM/ECLAIRs trigger, with an exposure time of 5791 s.
On-ground analysis of the EP-FXT data found an uncataloged X-ray source within the SVOM/ECLAIRs error region (Goto et al., GCN 46030). The position of the source is consistent with that of the optical counterpart candidate, and its X-ray flux shows a declining trend. The preliminary result for the X-ray source are as follow:
R.A., Decl. (J2000) = 337.3535, 27.0268 deg
Localization error radius = 10 arcsec
0.5-10 keV flux = 2.80e-12 erg/cm^ 2/s
Flux error = 1.83e-13 erg/cm^2/s (1 sigma)
Separation = 1.76 arcmin
Launched on January 9, 2024, EP is a space X-ray observatory to monitor the soft X-ray sky with X-ray follow-up capability (Yuan et al. 2022, Handbook of X-ray and Gamma-ray Astrophysics).