TITLE: GCN CIRCULAR NUMBER: 42140 SUBJECT: GRB 251006B/EP251006a: EP-FXT follow-up observation DATE: 25/10/07 13:03:20 GMT FROM: EP Team at NAOC/CAS <ep_ta@bao.ac.cn> Y.-H. I. Yin (HKU), M. H. Zhang, T. Y. Liu, H. Y. Ren and Z. X. Ling (NAO, CAS) on behalf of the Einstein Probe (EP) team: EP-FXT performed a follow-up observation of GRB 251006B/EP251006a (GCN 42131, GCN 42137, GCN 42139) at 2025-10-07T06:50:56 (UTC), about 11 hours after the WXT detection, with an exposure time of 2.7 ks. The source was also followed by several optical telescopes (GCN 42133, GCN 42138). Two uncatalogued sources were detected within the WXT error circle. Preliminary analyses on these sources are automatically conducted, and the details are listed as follows. Source 1: EPF_J024205.3-055701 RA (J2000): 40.5219 Dec (J2000): -5.9501 Flux: 3.25 x 10^-13 erg/s/cm^2 (observed, 0.5-10 keV) Flux_err: 9.45 x 10^-14 erg/s/cm^2 (1 sigma) Source 2: EPF_J024204.7-060206 RA (J2000): 40.5194 Dec (J2000): -6.0350 Flux: 3.52 x 10^-12 erg/s/cm^2 (observed, 0.5-10 keV) Flux_err: 4.30 x 10^-13 erg/s/cm^2 (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). View this GCN Circular online at https://gcn.nasa.gov/circulars/42140. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0LW...