TITLE: GCN CIRCULAR NUMBER: 43753 SUBJECT: EP260214a: COLIBRÍ optical upper limits DATE: 26/02/15 14:43:58 GMT FROM: Rosa L. Becerra at Instituto de Astronomía, UNAM <rbecerra@astro.unam.mx> Alan M. Watson (UNAM), Damien Dornic (CPPM), Rosa L. Becerra (UNAM), Stéphane Basa (UAR Pytheas), William H. Lee (UNAM), Edilberto Aguilar-Ruiz (UNAM), Jean-Luc Atteia (IRAP), Camila Angulo (UNAM), Dalya Akl (NYUAD), Sarah Antier (IJCLAB), Nathaniel R. Butler (ASU), Jean-Grégoire Ducoin (CPPM), Francis Fortin (IRAP), Leonardo García García (UNAM), Ramandeep Gill (UNAM), Noémie Globus (UNAM), Asuka Kuwata (UNAM), Nikos Mandarakas (LAM), Diego López-Cámara (UNAM), Francesco Magnani (CPPM), Enrique Moreno Méndez (UNAM), Margarita Pereyra (UNAM), Ny Avo Rakotondrainibe (LAM), Fredd Sánchez Álvarez (UNAM), Benjamin Schneider (LAM) and Antonio de Ugarte Postigo (LAM) report: We imaged the field of EP260214a (Li et al., GCN Circ. 43742) using the DDRAGO two-channel wide-field imager on the COLIBRÍ telescope. We observed from 2026-02-15 10:20 to 11:32 UTC (from 13.70 to 14.92 hours after the trigger) and obtained 53 minutes of exposure, in r and z filters. The data were reduced, calibrated, and analysed with the COLIBRÍ ASU pipeline. The photometry was calibrated using nearby stars from the PanSTARRS DR1 catalog, is in the AB system, and is not corrected for Galactic extinction. In the stacked images, we do not detect any new source at the refined FXT position (Li et al., GCN Circ. 43751) down to the following 3-sigma limits: r > 23.6 z > 22.2 These upper limits are consistent with the ones reported by SVOM/VT (Li et al. GCN Circ. 43746). We thank the staff of the Observatorio Astronómico Nacional on the Sierra de San Pedro Mártir and the COLIBRÍ and DDRAGO engineering teams. COLIBRÍ is an astronomical observatory developed and operated jointly by France (AMU, CNES and CNRS) and Mexico (UNAM and SECIHTI). It is located at the Observatorio Astronómico Nacional on the Sierra de San Pedro Mártir, Baja California, Mexico. View this GCN Circular online at https://gcn.nasa.gov/circulars/43753. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0LW...