GCN Circular 44742

SVOM/GRM team: Chen-Wei Wang, Shi-Jie Zheng, Yue Huang, Shao-Lin Xiong, Shuang-Nan Zhang (IHEP)

SVOM/ECLAIRs team: Marius Brunet (IRAP)

Report on behalf of the SVOM team:

SVOM/GRM was triggered in-flight by a bright short burst GRB 260530B (SVOM trigger reference: sb26053001) at 2026-05-30T06:00:05.600 UTC (T0).

With the event-by-event data downloaded through the X-band ground station, the GRM light curve shows that this burst consists of a single symmetrical smooth pulse with a T90 of 1.55 +0.20/-0.15 s in the 15-5000 keV band. 

The SVOM/GRM light curve can be found here:
https://www.bursthub.cn//admin/static/svgrb260530B.png

ECLAIRs was not collecting data at the time of this burst.

We note that this signal was detected near the NWC transmitter and may be associated with the artificial electron belt, so it is not yet clear whether it is a genuine astrophysical burst. 

The Space Variable Objects Monitor (SVOM) is a China-France joint mission led by the Chinese National Space Administration (CNSA, China), National Center for Space Studies (CNES, France) and the Chinese Academy of Sciences (CAS, China), which is dedicated to observing gamma-ray bursts and other transient phenomena in the energetic universe. GRM is developed by the Institute of High Energy Physics (IHEP) of CAS.

The SVOM point of contact for this burst is: Chen-Wei Wang (IHEP)(cwwang@ihep.ac.cn)