TITLE: GCN CIRCULAR NUMBER: 44566 SUBJECT: GRB 260510B: EP-FXT follow-up observation DATE: 26/05/12 02:31:52 GMT FROM: EP Team at NAOC/CAS <ep_ta@bao.ac.cn> A. Li (BNU), S.-Y. Fu (HUST), C.-Y. Wang (THU), R. Shi (PMO), Y. Liu (NAOC, CAS) on behalf of the Einstein Probe (EP) team: EP-FXT performed a follow-up observation of the SVOM/ECLAIRs-detected burst GRB 260510B (SVOM/sb26051001, Saccardi et al., GCN 44515). The follow-up obervation started at 2026-05-10T13:15:11 UTC, approximately 55 minutes after the SVOM trigger, with a total exposure time of 6.1 ks. On-ground analysis of the FXT data found an uncatalogued fading source at R.A., Dec. = 173.2323, -34.5399 (J2000) with an uncertainty of about 10 arcsec (radius, 90% C.L. statistical and systematic) within the ECLAIRs error circle. The average FXT 0.5-10 keV spectrum can be fitted with an absorbed power-law model, with the hydrogen column density fixed at the Galactic value and a photon index of 2.24 (-0.56/+0.60). The derived average unabsorbed flux in the 0.5-10 keV band is 1.17 (-0.3/+1.7)×10^-12 erg s^-1 cm^-2. 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/44566. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0LW...