TITLE: GCN CIRCULAR NUMBER: 45404 SUBJECT: GRB 260818A: SVOM/ECLAIRs refined analysis DATE: 26/08/19 20:26:12 GMT FROM: SVOM_group H. Yang, O. Godet (IRAP), W.-J. Xie (NAOC), Clara Plasse (HKU) 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 possible faint burst GRB 260818A (SVOM burst-id sb26081801, GCN 45391, trigger time T0 = 2026-08-18T01:04:36 UTC). The burst that triggered ECLAIRs shows a featureless light curve, and is detected from T0-82 s to T0 in the 8-120 keV energy band. The time-averaged spectrum from T0-82 s to T0 in the 5-120 keV is well fitted by a blackbody model with a temperature of (7 +2/-1) keV, a 4-120 keV photon flux of (0.26 +0.06/-0.05) photons/cm^2/s, and a corresponding 4-120 keV fluence of (7 +/-2)e-7 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: Hui Yang (IRAP) (hui.yang@cnrs.fr).