GCN Circular 44378
Subject
GRB 260412A: SVOM/ECLAIRs refined analysis
Event
Date
2026-04-21T13:31:47Z (a day ago)
From
SVOM_group <svomgroup@bao.ac.cn>
Via
Web form
Marius Brunet (IRAP), Wenjin XIE (NAOC), Olivier Godet (IRAP), Ziqi Wang (GXU), Zhiyong Liu(GZNU) 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 260412A (SVOM burst-id sb26041206 – GCN 44276, trigger time T0 = 2026-04-12T06:13:35 UTC), which was also detected by Fermi (GCN 44275, 44279), GECAM (GCN 44281) and HXMT (GCN 44294).
The burst that triggered ECLAIRs onboard shows a multiple peak lightcurve with late peaks at around T0+80s and T0+160s. The burst duration is T90 = 165.0 +2.6/-1.6 s in the 4-120 keV energy band.
The time-averaged spectrum from T0-3.5 s to T0+200.5 s in the energy range 4-120 keV is best fitted by a powerlaw model with best-fit parameters – alpha = -1.5 +/-0.3. With this model, the 4-120 keV fluence is 7.4 +/- 0.3 e-6 erg/cm^2.
Using the same Fermi/GBM time window as in Palafox et al. (GCN 44279), we retrieve a consistent photon index value when using a cutoff model and fixing Epeak at 210 keV.
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)