TITLE: GCN CIRCULAR NUMBER: 45306 SUBJECT: EP260806a: COLIBRÍ optical observations DATE: 26/08/07 10:01:00 GMT FROM: Antonio de Ugarte Postigo at LAM, CNRS <adeugartepostigo@gmail.com> Antonio de Ugarte Postigo (LAM), Enrique Moreno Méndez (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), Rosa L. Becerra (UNAM), Nathaniel R. Butler (ASU), Damien Dornic (CPPM), Jean-Grégoire Ducoin (CPPM), Francis Fortin (IRAP), Leonardo García-García (UNAM), Ramandeep Gill (UNAM), Noémie Globus (UNAM), Marion Guelfand (CPPM), Asuka Kuwata (UNAM), Massimiliano Lincetto (CPPM), Nikos Mandarakas (LAM), Diego López-Cámara (UNAM), Francesco Magnani (CPPM), Margarita Pereyra (UNAM), Fredd Sánchez Álvarez (UNAM), Benjamin Schneider (LAM), Alan M. Watson (UNAM) report: We imaged the field of the EP260806a (Li et al., GCN Circ. 45299) using the DDRAGO two-channel wide-field imager on the COLIBRÍ telescope. We observed from 2026-08-07 05:27:53 to 06:26:13 UTC (from 6.423 to 7.396 hours after the trigger) and obtained 16 minutes of exposure in the z and y filters. The data were reduced and coadded with the COLIBRÍ pipeline and analysed with STDWeb (Karpov 2025). The photometry was calibrated using nearby stars from the PanSTARRS catalog, is in the AB system, and is not corrected for Galactic extinction. After subtracting the template, we clearly detected the optical counterpart (He et al., GCN Circ. 45300; de Ugarte Postigo et al. GCN Circ. 45302; Eyles-Ferris GCN Circ. 45303; Ma et al. GCN Circ. 45304) at a preliminary magnitude of: z = 19.44 +/- 0.04 Further observations are ongoing. We thank the staff of the Observatorio Astronómico Nacional at Sierra de San Pedro Mártir, as well as the technical and engineering teams at CEA, CPPM, IRAP, LAM, OHP, OSU Pytheas, and UNAM. 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/45306. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0LW...