GCN Circular 42605

S. Antier (IJCLAB), M. Dennefeld (IAP), S. Schanne (CEA/Irfu), F. Lacreu (IAP) report on behalf of the SVOM mission team:

At 2025-11-06T19:56:37 UTC (T0), SVOM/ECLAIRs triggered and located the gamma-ray burst GRB 251106A (SVOM burst-id sb25110604).

The following trigger information was received on the ground with low latency by the SVOM VHF Alert Network.

The burst was detected both by the Count-Rate Trigger (CRT) and the Image Trigger (IMT), which produced a sequence of 16 alerts. IMT provided the alert with the best signal-to-noise-ratio in the image (SNR) of 11.02 in the [8-120] keV energy band over a time window of 163.84 seconds starting at 2025-11-06T19:55:40.

The localization of the best alert is R.A., Dec. 234.6169, 63.3716 degrees:
R.A. (J2000) = 15h38m28.05s
Dec. (J2000) = 63d22m17.83s
 with a 90% confidence level (C.L.) radius of 7.27 arcmin (including systematic error of 2 arcmin added in quadrature).

Due to sun constraints, 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 Sarah Antier: sarah.antier@ijclab.in2p3.fr.
Please contact the BA by email if you require additional information.