GCN Circular 45260
Subject
GRB 260727A: SVOM/ECLAIRs refined analysis
Event
Date
2026-07-30T23:55:12Z (2 months ago)
From
SVOM_group <svomgroup@bao.ac.cn>
Via
Web form
M. Brunet (IRAP), R. Li (YNAO), Z. Wang (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 260727A (SVOM burst-id sb26072701 – GCN 45220, trigger time T0 = 2026-07-27T00:22:02 UTC), which was also detected by SVOM/GRM (GCN 452457), AstroSat/CZTI (GCN 45225), Glowbug (GCN 45233), and Konus-Wind (GCN 45242).
The burst that triggered ECLAIRs onboard shows a multiple peak lightcurve. The burst duration is T90 = 66.5+/-2.5 s in the 4-120 keV energy band.
The time-averaged spectrum from T0-3.5 s to T0+112 s in the 5-120 keV energy range is best fitted by a powerlaw with an exponential cutoff model with alpha = -1.03 +/-0.03 and a peak energy = 72 +4/-3 keV. With this model, the 4-120 keV fluence is (1.38 +/-0.02)e-5 erg/cm^2 and the 4-120 keV photon flux is 3.17 +/-0.03 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)