TITLE: GCN CIRCULAR NUMBER: 43433 SUBJECT: FRB 20251229A: COLIBRÍ further inspection of the updated localization DATE: 26/01/17 00:23:03 GMT FROM: Rosa L. Becerra at Instituto de Astronomía, UNAM <rbecerra@astro.unam.mx> Rosa L. Becerra (UNAM), Noémie Globus (UNAM), Stéphane Basa (UAR Pytheas), William H. Lee (UNAM), Alan M. Watson (UNAM), Jean-Luc Atteia (IRAP), Edilberto Aguilar-Ruiz (UNAM), Dalya Akl (NYUAD), Camila Angulo (UNAM), Sarah Antier (IJCLAB), Nathaniel R. Butler (ASU), Damien Dornic (CPPM), Jean-Grégoire Ducoin (CPPM), Francis Fortin (IRAP), Leonardo García García (UNAM), Ramandeep Gill (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 reinspected our previous observations of the field of FRB 20251229A (Mulyk et al., GCN Circ. 43334) reported by Globus et al. (GCN Circ. 43431), focusing on the updated baseband localization provided by the CHIME/FRB Collaboration (Mason et al., GCN Circ. 43431). We analysed the data and performed image subtraction using STDWeb/STDPipe (Karpov 2025), with templates from the Pan-STARRS DR2 catalog (Flewelling et al. 2020). In this further inspection, we do not detect any new source or evidence for brightness variability of any object within the localization uncertainty region (Mason et al., GCN Circ. 43431), down to the following 5-sigma limits: r > 22.5, z > 21.5. 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/43433. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0LW...