GCN Circular 42637

Yehao Cheng (SWIFAR,YNU), Boting Wang (YNAO), Wenjin Xie, Donghua ZHAO (NAOC), Hatsunegoto Goto (Kanazawa Univ./CEA) report on behalf of the SVOM mission team:


At 2025-11-11T05:10:18 UTC (T0), SVOM/ECLAIRs triggered and located the gamma-ray burst GRB 251111A (SVOM burst-id sb25111101).

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 7 alerts. CRT provided the alert with the best signal-to-noise-ratio in the image (SNR) of 10.57 in the [5-20] keV energy band over a time window of 5.10 seconds starting at 2025-11-11T05:10:15.

The localization of the best alert is R.A., Dec. 32.3783, 5.2567 degrees:
R.A. (J2000) = 2h09m30.79s
Dec. (J2000) = 5d15m24.04s
 with a 90% confidence level (C.L.) radius of 7.55 arcmin (including systematic error of 2 arcmin added in quadrature).

SVOM slewed to this burst, but MXT and VT were in the occultation of the Earth.


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 Yehao Cheng: yhcheng@mail.ynu.edu.cn.
Please contact the BA by email if you require additional information.