GRB 251119A

C. Wu (NAOC), K.X. Gong (CHO), M. Brunet (IRAP), D. Turpin, S. Schanne, D. Gotz (CEA), U. Jacob (LUPM), report on behalf of the SVOM mission team:

At 2025-11-19T08:47:44 SVOM issued an alert with burst-id: sb25111901.

The following circular(s) have been published regarding this event: GCN 42757
Loading...
 
 , with the event labelled as GRB 251119A 

This event is not a GRB of astrophysical origin. After reprocessing the data with the full telemetry, this trigger is no longer considered as an astrophysical source but is due to coding noise from the Crab in the field of view.

We apologize for any inconvenience this may have caused.

The Burst Advocate (BA) on shift for this alert is Chao Wu: cwu@bao.ac.cn.
Please contact the BA by email if you require additional information.

C. Wu (NAOC), K.X. Gong (CHO), D. Turpin, S. Schanne, D. Gotz (CEA), U. Jacob (LUPM) report on behalf of the SVOM mission team:

At 2025-11-19T08:47:44 UTC (T0), SVOM/ECLAIRs triggered and located the gamma-ray burst GRB 251119A (SVOM burst-id sb25111901).

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 Count-Rate Trigger (CRT), which produced a sequence of 3 alerts. CRT provided the alert with the best signal-to-noise-ratio in the image (SNR) of 7.89 in the [5-8] keV energy band over a time window of 20.40 seconds starting at 2025-11-19T08:47:23 (Tb).

The localization of the best alert is R.A., Dec. 84.4289, 12.2431 degrees:
R.A. (J2000) = 5h37m42.93s
Dec. (J2000) = 12d14m35.17s
 with a 90% confidence level (C.L.) radius of 9.96 arcmin (including systematic error of 2 arcmin added in quadrature).

We notice that the Crab is located near the border of the field of view and about 9.8 degrees away from the burst’s position with a SNR of 9.0 (similar to the burst’s SNR) in the sky image.

SVOM slewed to the burst position.

SVOM/MXT began observing the field at 08:51:08 UTC, 206 seconds after T0. Using onboard processed data, no source was detected in 225 seconds.
The SVOM/MXT team is waiting for the full dataset to detect and localise the possible SVOM/MXT counterpart.

VT began observing the field after the slew. The analysis of the data will be published in a future circular.

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 Chao Wu: cwu@bao.ac.cn.
Please contact the BA by email if you require additional information.