TITLE:   GCN CIRCULAR
NUMBER:  46086
SUBJECT: GRB 261029A: EP-FXT follow-up observation
DATE:    26/10/29 09:33:51 GMT
FROM:    EP Team at NAOC/CAS <ep_ta@bao.ac.cn>

C. K. Kan (HKU), D. F. Hu, Y. L. Hua (PMO,CAS), H. W. Pan (NAO, CAS) on behalf of the Einstein Probe (EP) team:

EP-FXT performed a follow-up observation of GRB 261029A, detected by SVOM/ECLAIRs (Goto
 et al., GCN 46072), at 2026-10-29 02:14:00 (UTC), about 47 minutes after the SVOM/ECLAIRs trigger, with an exposure time of 1936 s.

On-ground analysis of the EP-FXT data identified an uncataloged X-ray source located 4.95 arcmin from the SVOM/ECLAIRs position (Goto et al., GCN 46072), but only 1.67 arcsec from the GOTO optical counterpart candidate (O'Neill et al., GCN 46073). The preliminary results for the X-ray source are as follows:

Source name: EPF_J003516.3+342959
R.A., Decl. (J2000) = 8.8178, 34.4997 deg
Localization error radius = 10 arcsec
0.5-10 keV flux = 2.822e-11 erg/cm^ 2/s
Flux error = 1.28e-12 erg/cm^2/s (1 sigma)

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).