TITLE: GCN CIRCULAR NUMBER: 45050 SUBJECT: EP260626a: EP-FXT follow-up observation DATE: 26/06/27 15:28:42 GMT FROM: EP Team at NAOC/CAS <ep_ta@bao.ac.cn> J. P. Chen (SYSU), K. J. Zhang, D. Zhu (YNU), W. D. Zhang (NAO, CAS) on behalf of the Einstein Probe (EP) team: EP-FXT performed a follow-up observation of EP260626a (J. P. Chen et al., GCN 45047) approximately 10.8 hours after the WXT detection, with an exposure time of 6.1 ks. An uncatalogued X-ray source was detected within the WXT error circle at R.A. = 277.4479, Dec. = 21.2498 (J2000), with a positional uncertainty of 10.0 arcsec (radius, 90% C.L. statistical and systematic). The FXT spectrum can be fitted with an absorbed powerlaw with a hydrogen column density fixed at the Galactic value of 2.04 x 10^21 cm^-2 and a photon index of 2.13 (+0.6, -0.6). The derived unabsorbed 0.5-10 keV flux is approximately 9.3 (+4.5, -2.1) x 10^-14 erg/s/cm^2. The uncertainties are at the 90% confidence level for the above parameters. No optical counterpart has been detected (R. A. J. Eyles-Ferris et al., GCN 45048; Francesco Magnani et al., GCN 45049). 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). View this GCN Circular online at https://gcn.nasa.gov/circulars/45050. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0LW...