Gamma-ray Burst 251104A

(All information courtesy of the instrument teams.)

Previous IAU Circulars

• none

• GCN Circular #42581
  M.G. Bernardini (INAF-OAB, LUPM), M. Pillas (IAP), N. Dagoneau (CEA), F. Lacreu (IAP)
  At 2025-11-04T17:30:58 UTC (T0), SVOM/ECLAIRs triggered and located the gamma-ray burst GRB 251104A (SVOM burst-id sb25110404).
  The following trigger information was received on the ground with low latency by the SVOM VHF Alert Network.
  The burst was only detected by the Image Trigger (IMT), which produced a sequence of 6 alerts. IMT provided the alert with the best signal-to-noise-ratio in the image (SNR) of 10.82 in the [5-8] keV energy band over a time window of 655.36 seconds starting at 2025-11-04T17:28:14.
  The localization of the best alert is R.A., Dec. 26.5099, 15.5077 degrees:

  R.A. (J2000) = 1h46m02.39s
  Dec. (J2000) = 15d30m27.56s
  

  with a 90% confidence level (C.L.) radius of 7.39 arcmin (including systematic error of 2 arcmin added in quadrature).
  No immediate slew was performed on this burst. No X-ray observation could be performed by SVOM/MXT for the time being. No optical observation could be performed by SVOM/VT for the time being.
  The Space-based multi-band astronomical Variable Objects Monitor (SVOM) is a China-France joint mission led by the Chinese National Space Administration (CNSA), French Space Agency (CNES), and the Chinese Academy of Sciences (CAS), which is dedicated to observing gamma-ray bursts and other transient phenomena in the energetic universe. SVOM/ECLAIRs was developed jointly by CNES, CEA-IRFU, CNRS-IRAP, CNRS-APC. SVOM/GRM was developed by the Institute of High Energy Physics (IHEP) of CAS. SVOM/MXT was developed jointly by CNES, CEA-IRFU, CNRS-IJCLab, University of Leicester, MPE.
  The Burst Advocate (BA) on shift for this alert is Maria Grazia Bernardini: maria.bernardini@inaf.it. Please contact the BA by email if you require additional information.
• GCN Circular #42592
  Benjamin Schneider (LAM), Stéphane Basa (UAR Pytheas), Camila Angulo (UNAM), William H. Lee (UNAM), Alan M. Watson (UNAM), Jean-Luc Atteia (IRAP), 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), Noémie Globus (UNAM), Kin Ocelotl López (UNAM), Diego López-Cámara (UNAM), Francesco Magnani (CPPM), Enrique Moreno Méndez (UNAM), Margarita Pereyra (UNAM), Ny Avo Rakotondrainibe (LAM), Fredd Sánchez Álvarez (UNAM), and Antonio de Ugarte Postigo (LAM):
  We imaged the field of the SVOM GRB 251104A (Bernardini et al., GCN Circ. 42581) using the DDRAGO wide-field, two-channel imager on the SVOM/COLIBRÍ (FM-GFT) telescope. We observed from 2025-11-05 05:32:28 to 06:59:02 UTC (from 12.02 to 13.46 hours after the trigger) and obtained 64 minutes of exposure in the r and z filters. At the time of the observation the GRB was about 6 degrees from the full Moon.
  The data were reduced and coadded with the COLIBRÍ pipeline and analyzed with STDWeb/STDPipe (Karpov 2025). The photometry was calibrated using nearby stars from the PanSTARRS catalog, is in the AB system, and is not corrected for Galactic extinction.
  In the stacked image, we do not detect any new source at the ECLAIRs source position (Bernardini et al., GCN Circ. 42581) down to the following 5-sigma limit:

  r > 21.3
  z > 20.8
  

  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.