GCN Circular 45429

Subject

GRB 260822A: SVOM/COLIBRÍ (FM-GFT) possible optical counterpart candidate

Event

GRB 260822A

Date

2026-08-23T09:16:01Z (18 hours ago)

Edited On

2026-08-23T21:14:11Z (6 hours ago)

From

Stephane Basa at UAR Pytheas/OHP, LAM <stephane.basa@lam.fr>

Edited By

Judith Racusin at NASA/GSFC <judith.racusin@nasa.gov> on behalf of Stephane Basa at UAR Pytheas/OHP, LAM <stephane.basa@lam.fr>

Via

Web form

Noémie Globus (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), Marion Guelfand (CPPM), Asuka Kuwata (UNAM), Massimiliano Lincetto (CPPM), Nikos Mandarakas (LAM), Diego López-Cámara (UNAM), Francesco Magnani (CPPM), Enrique Moreno Méndez (UNAM), Margarita Pereyra (UNAM), Fredd Sánchez Álvarez (UNAM), Benjamin Schneider (LAM), Antonio de Ugarte Postigo (LAM),  Alan M. Watson (UNAM) and Damien Turpin (CEA/Irfu) report:

We imaged the field of the SVOM GRB 260822A (Schanne et al., GCN Circ. 45422Loading...
 
 ) using the DDRAGO two-channel wide-field imager on the SVOM/COLIBRÍ (FM-GFT) telescope. We observed from 2026-08-23 04:56 to 08:40 UTC (from 12.1 to 15.8 hours after the trigger) and obtained 82 minutes of simultaneous exposure in the r and z filters.

The data were reduced and coadded and analysed with the COLIBRÍ and ASU pipelines. The photometry was calibrated using nearby stars from the PanSTARRS DR2 catalog, is in the AB system, and is not corrected for Galactic extinction.

In the stacked image, we tentatively detected a faint, uncatalogued source in both bands, consistent with the SVOM/ECLAIRs error circle at:
  RA (J2000) = 00:09:45.57 = 2.43988 deg
  Dec (J2000) = +01:23:23.2 = 1.38978 deg,

with an estimated astrometric uncertainty of 0.5 arcsec.

The preliminary magnitude derived for that source was:
  r = 22.88 ± 0.09
  z = 22.08 ± 0.14

We encourage additional observations to confirm the nature of the source.

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.