GCN Circular 45538
Subject
GRB 260909A: SVOM/GRM observation
Event
Date
2026-09-09T16:19:04Z (5 days ago)
From
Chenwei Wang at IHEP <cwwang@ihep.ac.cn>
Via
Web form
SVOM/GRM team: Chen-Wei Wang, Yang-Zhao Ren, Yue Huang, Shi-Jie Zheng, Shao-Lin Xiong, Shuang-Nan Zhang (IHEP)
SVOM/ECLAIRs team: Cyril Lachaud (APC)
Report on behalf of the SVOM team:
SVOM/GRM was triggered in-flight by GRB 260909A (SVOM trigger reference: sb26090910) at 2026-09-09T11:18:02.000 (T0), which was also detected by SVOM/ECLAIRs (A. Saccardi et al, GCN 45534).
With the event-by-event data downloaded through the X-band ground station, the GRM light curve shows that this burst consists of multi-peaks structure with a T90 of 26.6 +2.6/-2.2 s in the 15-5000 keV band.
The SVOM/GRM light curve can be found here:
https://www.bursthub.cn/gcn/2026/svgrb260909A.png
With the localization from SVOM/ECLAIRs, the time-averaged spectrum from T0-25 s to T0+20 s is best fitted a power law function with an exponential high-energy cutoff. The power law index is -1.45 +0.25/-0.24 and the cutoff energy, parameterized as Epeak, is 37 +5/-7 keV. The event fluence (10-1000 keV) in this time interval is (4.85 +0.27/−0.26)E-06 erg/cm^2.
The localization of GRB 260909A in the 'Amati' relation diagram is shown at: https://www.bursthub.cn/gcn/2026/svgrb260909A_amati.png
The localization of GRB 260909A in the 'Yonetoku' relation diagram is shown at: https://www.bursthub.cn/gcn/2026/svgrb260909A_yonetoku.png
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/GRM point of contact for this burst is: Chen-Wei Wang (IHEP) (cwwang@ihep.ac.cn)