TITLE: GCN CIRCULAR NUMBER: 44541 SUBJECT: GRB 260510C: EP-FXT follow-up observation DATE: 26/05/11 10:10:16 GMT FROM: EP Team at NAOC/CAS <ep_ta@bao.ac.cn> S.-Y. Fu (HUST), A. Li (BNU), 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 260510C (SVOM/sb26051004, Gotz et al., GCN 44521), which also triggered Fermi-GBM (Fermi GBM team, GCN 44520) and MAXI/GSC (Iwakiri et al., GCN 44526). The follow-up obervation started at 2026-05-10T18:03:40 UTC, approximately 50 minutes after the SVOM trigger, with a total exposure time of 5370 s. On-ground analysis of the FXT data found an uncatalogued fading source at R.A., Dec. = 157.9391, 2.837 (J2000) with an uncertainty of about 10 arcsec (radius, 90% C.L. statistical and systematic) within the ECLAIRs error circle, which is spatially consistent with the optical counterpart (Angulo et al., GCN 44530; Li et al., GCN 44540). 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 2.15 (-0.07/+0.07). The derived average unabsorbed flux in the 0.5-10 keV band is 4.1 (-0.1/+0.1)×10^-11 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/44541. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0LW...