GCN Circular 45344

Subject

GRB260809A/EPF_J234751.2+210212: EP-FXT follow-up observation

Event

GRB 260809A

Date

2026-08-10T12:12:39Z (13 days ago)

From

EP Team at NAOC/CAS <ep_ta@bao.ac.cn>

Via

Web form

X. X. Sun(NAO, CAS), Q. J. Huang (PMO, CAS), K. J. Zhang(YNU), J. P. Chen (SYSU), Z. X. Ling(NAO, CAS) on behalf of the Einstein Probe (EP) team:

EP-FXT performed a follow-up observation of GRB 260809A detected by SVOM/ECLAIRs (Brunet et al., GCN 45331

). The observation started at 2026-08-09 17:30:29 (UTC), about 2.55 hr after the SVOM trigger, with a total exposure time of around 3 ks.

On-ground analysis of the FXT data found a source EPF_J234751.2+210212 at R.A. = 356.9632, deg and Dec. = 21.0368 deg (J2000) with an uncertainty of 10 arcsec (radius, 90% C.L. statistical and systematic). The source position is consistent with the optical counterpart (Li et al., GCN 45336

; Adami et al., GCN ; Rajabov et al., GCN ; Izzo et al., GCN ; Basa et al. 45342). The observed flux is approximately 4.5 × 10^-12 erg s^-1 cm^-2 in the 0.5-10 keV energy band.

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).