GCN Circular 43892
Subject
GRB 260228A: SVOM/COLIBRÍ (FM-GFT) optical upper limit
Event
Date
2026-03-01T17:32:00Z (3 days ago)
Edited On
2026-03-01T23:55:08Z (3 days ago)
From
nikos.mandarakas@lam.fr
Edited By
Judith Racusin at NASA/GSFC <judith.racusin@nasa.gov> on behalf of nikos.mandarakas@lam.fr
Via
Web form
Nikos Mandarakas (LAM), Margarita Pereyra (UNAM), Nathaniel R. Butler (ASU), Rosa L. Becerra (UNAM), Alan M. Watson (UNAM), Jean-Luc Atteia (IRAP), Stéphane Basa (UAR Pytheas), William H. Lee (UNAM), Edilberto Aguilar-Ruiz (UNAM), Camila Angulo (UNAM), Dalya Akl (NYUAD), Sarah Antier (IJCLAB), Damien Dornic (CPPM), Jean-Grégoire Ducoin (CPPM), Francis Fortin (IRAP), Leonardo García García (UNAM), Ramandeep Gill (UNAM), Noémie Globus (UNAM), Asuka Kuwata (UNAM), Diego López-Cámara (UNAM), Francesco Magnani (CPPM), Enrique Moreno Méndez (UNAM), Ny Avo Rakotondrainibe (LAM), Fredd Sánchez Álvarez (UNAM), Benjamin Schneider (LAM), Antonio de Ugarte Postigo (LAM), Yashaswi Julakanti (U. Leicester), Rob Eyles-Ferris(U. Leicester) report:
We imaged the field of the SVOM GRB 260228A (Julakanti et al., GCN Circ. 43882) using the DDRAGO wide-field imager on the SVOM/COLIBRÍ (FM-GFT) telescope. We observed from 2026-03-01 07:28 to 11:52 UTC (from 10.55 to 14.96 hours after the trigger) and obtained 120 minutes of exposure in the r filter and 129 minutes of exposure in the z filter.
The data were reduced, coadded, calibrated, and analysed with the COLIBRÍ ASU pipeline. The photometry was calibrated using nearby stars from the Pan-STARRS DR1 catalog, is in the AB system, and is not corrected for Galactic extinction.
In the stacked image, comparing to Pan-STARRS and Legacy Survey (Dey et al. 2019) images, we do not detect any new source within the ECLAIRs uncertainty region (Julakanti et al., GCN Circ. 43882) down to the following 5-sigma limits:
r > 23.3
z > 22.5
This upper limit is consistent with the one reported by Li et al. (GCN Circ. 43886).
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.