TITLE: GCN CIRCULAR NUMBER: 44489 SUBJECT: EP260507a: LCO optical counterpart DATE: 26/05/07 15:16:19 GMT FROM: Rob Eyles-Ferris at U of Leicester G. Corcoran (UCD), R. A. J. Eyles-Ferris (Leicester), J. A. Chácon (PUC), J. N. D. van Dalen (Radboud), F. E. Bauer (SSI and UTA), P. G. Jonker (Radboud), A. J. Levan (Radboud & Warwick) and D. B. Malesani (DAWN/NBI and Radboud) report on behalf of a larger collaboration: We observed the field of the fast X-ray transient EP260507a (Fu et al., GCN 44488) using an LCO 1m telescope located at the Siding Spring Observatory (Australia) equipped with the SINISTRO instrument. We obtained 6x300s exposures in the SDSS-r filter starting at 2026-05-07 14:34:48 (~47 minutes after the trigger). Within the EP/FXT error region (Fu et al., GCN 44488), we detect a likely optical counterpart at a position of (J2000): RA 13:47:35.57 (206.89822) Dec -22:14:08.40 (-22.23566) We measure a magnitude of r = 21.21 +/- 0.07 (AB) calibrated to PanSTARRS and not corrected for Galactic extinction.