TITLE: GCN CIRCULAR NUMBER: 43452 SUBJECT: EP260119a: LCO optical observations DATE: 26/01/19 13:02:37 GMT FROM: Daniele Bjørn Malesani at Cosmic Dawn Center, Niels Bohr Institute <daniele.malesani@nbi.ku.dk> R. A. J. Eyles-Ferris (Leicester), J. A. Quirola-Vasquez (Radboud), G. Corcoran (UCD), D. B. Malesani (DAWN-NBI and Radboud), A. van Hoof (Radboud), A. Martin-Carrillo (UCD), P. G. Jonker (Radboud), A. J. Levan (Radboud and Warwick) report on behalf of a larger group: We observed the field of the fast X-ray transient EP260119a (Jiang et al., GCN 43447; Cheng et al., GCN 43449) using an LCO 1m telescope located at the McDonald Observatory (Texas, USA) equipped with the SINISTRO instrument. A series of 3x300 s exposures was taken in each of the SDSS-r and SDSS-z filters, starting on 2026-01-19 at 09:40:45 UT (9.45 hr after the trigger). The optical counterpart discovered by COLIBRÍ (Fortin et al., GCN 43450) is detected in our images, with magnitudes: r = 22.83 +- 0.33 (9.54 hr after trigger) z = 20.26 +- 0.13 (9.81 hr after trigger) These values are in the AB system, are calibrated against the Pan-STARRS survey, and are not corrected for Galactic extinction. Our measurements confirm the red r-z color of the afterglow (Fortin et al., GCN 43450). No host galaxy is detected in the r band in a stack of archival CFHT images, down to a limiting magnitude r > 24.5. View this GCN Circular online at https://gcn.nasa.gov/circulars/43452. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0LW...