TITLE: GCN CIRCULAR NUMBER: 43408 SUBJECT: GRB 260114A: COLIBRÍ optical upper limits DATE: 26/01/15 04:42:41 GMT FROM: Camila Angulo Valdez at UNAM <camiangulo@astro.unam.mx> Camila Angulo (UNAM), Jean-Grégoire Ducoin (CPPM), Rosa L. Becerra (UNAM), Stéphane Basa (UAR Pytheas), William H. Lee (UNAM), Alan M. Watson (UNAM), Edilberto Aguilar-Ruiz (UNAM), Jean-Luc Atteia (IRAP), Dalya Akl (NYUAD), Sarah Antier (IJCLAB), Nathaniel R. Butler (ASU), Damien Dornic (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): We imaged the field of the Swift GRB 260114A (Eyles-Ferris et al., GCN Circ. 43396), also detected by Fermi (Fermi GBM Team, GCN Circ. 43395; E. Bissaldi et al. GCN Circ. 43400), GECAM-B (Ren et al., GCN Circ. 43402), SVOM/GBM (SVOM/GRM team, GCN Circ. 43404), using the DDRAGO two-channel wide-field imager on the COLIBRÍ telescope. We observed from 2026-01-15 02:01 to 03:22 UTC (from 14.3 to 15.7 hours after the trigger) and obtained 63 minutes of simultaneous exposure in the r and z filters. The data were reduced and coadded with the COLIBRÍ ASU pipeline and analysed with STDWeb (Karpov 2025). The photometry was calibrated using nearby stars from the PanSTARRS DR1 catalog, is in the AB system, and is not corrected for Galactic extinction. After performing image subtraction of our stacked images against Legacy Survey (Dey et al. 2019) using STDWeb (Karpov 2025), we do not detect any new source at the XRT source position (Eyles-Ferris et al., GCN Circ. 43396) or the optical counterpart previously reported by GMG (Li et al., GCN Circ. 43398) and the Mondy observatory (Volnova et al., GCN Circ. 43401) down to the following 3-sigma limits: r > 24.1, z > 22.7. These upper limits are consistent with later reports from MASTER (Lipunov et al., GCN Circ. 43403), NOT (Corcoran et al., GCN Circ. 43406) and TNG (Brivio et al., GCN Circ. 43407). 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/43408. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0LW...