GCN Circular 45960
Subject
EP261015a: COLIBRÍ optical observations
Event
Date
2026-10-16T08:53:51Z (20 hours ago)
From
damien dornic <damiendornic@gmail.com>
Via
Web form
Enrique Moreno Méndez (UNAM), Damien Dornic (CPPM), Jean-Grégoire Ducoin (CPPM), Stéphane Basa (UAR Pytheas), William H. Lee (UNAM), Edilberto Aguilar-Ruiz (UNAM), Jean-Luc Atteia (IRAP), , Dalya Akl (NYUAD), Sarah Antier (IJCLAB), Rosa L. Becerra (UNAM), Nathaniel R. Butler (ASU), Damien Dornic (CPPM), Francis Fortin (IRAP), Leonardo García-García (UNAM), Ramandeep Gill (UNAM), Camila Angulo (UNAM), Noémie Globus (UNAM), Asuka Kuwata (UNAM), Massimiliano Lincetto (CPPM), Marion Guelfand (CPPM), Nikos Mandarakas (LAM), Diego López-Cámara (UNAM), Francesco Magnani (CPPM), Margarita Pereyra (UNAM), Fredd Sánchez Álvarez (UNAM), Benjamin Schneider (LAM), Antonio de Ugarte Postigo (LAM), Alan M. Watson (UNAM), report:
We imaged the field of the EP 261005a (Li et al, GCN Circ. 45956) using the DDRAGO two-channel wide-field imager on the COLIBRÍ telescope. We observed from 2026-10-16T04:52:09.644 to 2026-10-16T06:15:23.681 UTC (from 15.61 to 17.00 hours after the trigger) and obtained 62 minutes of exposure in the r filter.
The data were reduced, coadded and analysed with the CPPM COLIBRÍ pipeline. The photometry was calibrated using nearby stars from the PanSTARRS DR2 catalog, is in the AB system, and is not corrected for Galactic extinction.
After subtracting template Legacy Survey image, we clearly detected the optical counterpart reported by Corcoran et al., GCN Circ. 45955, at a preliminary magnitude of:
r mag = 23.04 +/- 0.19
Further observations and analysis 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.