TITLE:   GCN CIRCULAR
NUMBER:  45871
SUBJECT: GRB 261007A: SVOM/ECLAIRs refined analysis
DATE:    26/10/09 08:19:53 GMT
FROM:    SVOM_group <svomgroup@bao.ac.cn>

N. Dagoneau (CEA), M. Brunet, J.-L. Atteia, O. Godet (IRAP) 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 261007A (SVOM burst-id sb26100701, GCN 45824, trigger time T0 = 2026-10-07T05:42:03 UTC).
 
The burst was detected by ECLAIRs about 134 sec after Fermi (GCN 45830) and GRM (GCN 45824). This is due to the fact that SVOM was in the SAA region and ECLAIRs was not collecting data until 05:40:34 UT. As a consequence, ECLAIRs triggered on a low intensity tail following the bright prompt emission or on the early afterglow.
 
The burst duration, seen by ECLAIRs, estimated through the imaging technique is about 184 sec in the 4-120 keV energy band (from T0-89 s to T0+95 s, i.e. from 05:40:34 UT to 05:43:38 UT).
 
The time-averaged spectrum, in this time window, in the 5-120 keV energy range is best fitted by a powerlaw model, with alpha = -1.9 +/- 0.2. With this model, the 4-120 keV fluence is (0.83 ± 0.19)*e-6 erg/cm^2 and the 4-120 keV photon flux is (1.98 ± 0.24)*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:  Nicolas Dagoneau (nicolas.dagoneau at cea.fr)