TITLE:   GCN CIRCULAR
NUMBER:  45433
SUBJECT: EP260822a: EP-FXT non-detection and upper limit
DATE:    26/08/24 05:19:05 GMT
FROM:    EP Team at NAOC/CAS <ep_ta@bao.ac.cn>

J. P. Feng, B. Zhang (USTC), Y. Q. Zhao (PRIC, USTC) and H. Sun (NAO, CAS) on behalf of the Einstein Probe (EP) team:

EP-FXT observed the field of EP260822a (Feng et al., GCN 45428) for 2825 seconds starting at 2026-08-23T05:39:06, around 13.5 hours after the detection by EP-WXT. No significant X-ray source is detected within the 2.6 arcmin radius of the EP-WXT position (Feng et al., GCN 45428) . The derived 0.5-10 keV flux upper limit is 7.55e-14 erg/cm^2/s, assuming a powerlaw intrinsic emission with a photon index of 2 and fixed galactic absorption.

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).