GCN Circular 45553
Subject
GRB 260909A: SVOM/ECLAIRs refined analysis
Event
Date
2026-09-11T14:27:15Z (4 days ago)
From
SVOM_group <svomgroup@bao.ac.cn>
Via
Web form
M. Brunet, O. Godet (IRAP) , W.-J. Xie (NAOC), A. Saccardi, S. Schanne (CEA/Irfu), C. Plasse (HKU), A. Li (BNU), report on behalf of the SVOM/ECLAIRs team:
Using the event-by-event data downloaded through the X-band ground station, we report further analysis of SVOM/ECLAIRs observations of GRB 260909A (SVOM burst-id sb26090910 – GCN 45534, trigger time T0 = 2026-09-09T11:18:01 UTC).
The burst that triggered ECLAIRs onboard shows a multiple peak lightcurve. The burst duration estimated through the imaging technique is T90 = 47 +2/-3 s in the 4-120 keV energy band.
The time-averaged spectrum from T0-16 s to T0+31 s in the 5-120 keV energy range is best fitted by a powerlaw model, with alpha = -1.23 +/-0.07. With this model, the 4-120 keV fluence is (9.4 +/-0.8)e-6 erg/cm^2 and the 4-120 keV photon flux is 4.5 +/-0.3 ph/cm^2/s.
All the quoted errors are at the 68% confidence level.
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. ECLAIRs was developed jointly by CNES, CEA-IRFU, CNRS-IRAP, CNRS-APC.
The SVOM/ECLAIRs point of contact for this burst is: Marius Brunet (IRAP) (marius.brunet at utoulouse.fr)