TITLE:   GCN CIRCULAR
NUMBER:  41842
SUBJECT: GRB 250910A: SVOM/ECLAIRs refined analysis
DATE:    25/09/16 16:03:05 GMT
FROM:    SVOM_group <svomgroup@bao.ac.cn>

Baptiste Hubert, Nicolas Dagoneau, Stéphane Schanne (CEA), Jean-Luc Atteia (IRAP), Frédéric Piron (LUPM), Yinuo Ma, Donghua Zhao, Wenjin Xie (NAOC)

Using the event-by-event data downloaded through the X-band ground station, we report further analysis of ECLAIRs observations of GRB 250910A (SVOM burst-id sb25091001). 

The burst that triggered ECLAIRs (GCN 41769) consists of a broad structure with a duration of T90 = 22 -2/+3 s in the 4-20 keV energy band. 

The time-averaged spectrum from T0-15.5 s to T0+6.7 s (T0 = 2025-09-10T03:16:30) in the energy range 4-120 keV is best fitted by a power-law model with photon index 1.7 +/-0.2. With this model, the 4-120 keV flux is (2.2 -0.4/+0.2)e-08 erg/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 (CEA) (nicolas.dagoneau at cea.fr)