TITLE: GCN CIRCULAR NUMBER: 43516 SUBJECT: GRB 251222A: SVOM/ECLAIRs refined analysis DATE: 26/01/26 11:12:41 GMT FROM: SVOM_group <svomgroup@bao.ac.cn> Hui Yang, Sebastien Guillot, Olivier Godet, Marius Brunet, Guangxuan Lan (IRAP) Using the event-by-event data downloaded through the X-band ground station, we report further analysis of ECLAIRs observations of GRB 251222A (SVOM burst-id sb25122206, GCN 43188). The burst that triggered ECLAIRs consists of multiple peaks, and is detected for more than 200 s in the 4-120 keV energy band. The time-averaged spectrum before the slew from T0-14 s to T0+37 s (T0 = 2025-12-22T17:05:46) in the energy range 5-120 keV is best fitted by a cutoff power-law model with a photon index of 1.3+/-0.1, an Ecut of 54(+29/-15) keV, giving a corresponding 4-120 keV flux of (4.9+/-0.3)e-8 erg/cm^2/s. The spectrum from T0+162 s to T0+192 s after the slew in the energy range 5-120 keV is well fitted by a power-law model with a photon index of 2.4 +/-0.2 giving a corresponding 4-120 keV flux of (9+/-1)e-9 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: Hui Yang (IRAP) (hyang@irap.omp.eu) View this GCN Circular online at https://gcn.nasa.gov/circulars/43516. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0LW...