TITLE: GCN CIRCULAR NUMBER: 45443 SUBJECT: GRB 260809A: SVOM/ECLAIRs refined analysis DATE: 26/08/26 08:39:21 GMT FROM: SVOM_group <svomgroup@bao.ac.cn> M. Brunet, H. Yang, O. Godet (IRAP), F. Piron (LUMP) 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 the faint burst GRB 260809A (SVOM burst-id sb26080907, GCN 45331, trigger time T0 = 2026-08-09T14:57:33 UTC), also detected as a sub-threshold event by Fermi/GBM (GCN 45366). The burst that triggered ECLAIRs shows a multiple peak light curve, and is detected from T0-24 s to T0+19 s in the 4-120 keV energy band. The time-averaged spectrum from T0-24 s to T0+19 in the 5-120 keV is well fitted by a power-law model with a photon index of -1.3+/-0.2, a 4-120 keV photon flux of 0.76 +0.06/-0.20 photons/cm^2/s, and a corresponding 4-120 keV fluence of (1.4 +/-0.3)e-6 erg/cm^2. 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@utoulouse.fr). View this GCN Circular online at https://gcn.nasa.gov/circulars/45443. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0LW...