GCN Circular 43663
Subject
GRB 260208B: EP-FXT observation
Event
Date
2026-02-09T11:06:20Z (18 hours ago)
From
EP Team at NAOC/CAS <ep_ta@bao.ac.cn>
Via
Web form
S. Q. Jiang, H. N. Yang, Y. L. Wang, Y. Liu (NAO, CAS), Z. H. Yang, Q. C. Zhao (IHEP, CAS) on behalf of the Einstein Probe (EP) team:
EP-FXT performed a follow-up observation on GRB 260208B detected by Fermi/GBM (The Fermi GBM team, GCN 43638; Preis & Greiner, GCN 43639; Sonawane et al., GCN 43649), Fermi/LAT (Longo et al., GCN 43647) and SVOM/GRM (Luo et al., GCN 43650) at 2026-02-09T06:37:35 (UTC), about 20.748 hours after the Fermi/GBM trigger.
Two uncatalogued X-ray sources are detected around the Fermi/LAT error circle.
Preliminary informations are listed as follows:
Source 1: EPF_J063834.1-135348
RA (J2000): 99.6419
Dec (J2000): -13.8965
Flux: 1.12 x 10^-13 erg/cm^2/s (observed, 0.5-10 keV)
Source 2: EPF_J063827.9-134635
RA (J2000): 99.6162
Dec (J2000): -13.7764
Flux: 0.96 x 10^-13 erg/cm^2/s (observed, 0.5-10 keV)
The position is consistent with the source 1 detected by Swift-XRT (Evans et al., GCN 43651) and the optical candidate detected by SVOM/VT (Li et al., GCN 43659).
The position uncertainties of the above sources are about 20 arcsec in radius (90% C.L. statistical and systematic). The current result is based on the FXT on-board alert and will be updated when the telemetry data are received..
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).