GCN Circular 45681
Subject
GRB 260917B:: SVOM/ECLAIRs refined analysis
Event
Date
2026-09-21T14:58:07Z (3 days ago)
From
SVOM_group <svomgroup@bao.ac.cn>
Via
Web form
H. Yang, M. Brunet, O. Godet (IRAP), N. Dagoneau (CEA), K. Liu (USTC), C. Wu (NAOC)
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 260917B (SVOM burst-id sb26091701 – GCN 45606, trigger time T0 = 2026-09-17T03:52:21 UTC).
The burst that triggered ECLAIRs onboard shows a broad bump from T0 - 18 s to T0 + 17 s. The burst duration estimated through the imaging technique is T90 = 35 +/- 6 s in the 4-120 keV energy band.
The time-averaged spectrum from T0 - 18 s to T0 + 17 s in the 5-120 keV energy range is best fitted by a powerlaw model, with alpha = -1.4 +/- 0.1. With this model, the 4-120 keV fluence is (7.4 +/- 0.8)e-7 erg/cm^2 and the 4-120 keV photon flux is (5.7 +/- 0.5)e-1 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: Hui Yang (hui.yang at cnrs.fr)