TITLE: GCN CIRCULAR NUMBER: 45229 SUBJECT: GRB 260726A: SVOM ECLAIRs improved position and MXT possible detection of a counterpart DATE: 26/07/27 17:05:01 GMT FROM: SVOM_group <svomgroup@bao.ac.cn> M. Brunet (IRAP), P. Maggi (ObAS), D. Götz, D. Turpin (CEA), Ruizhi Li (YNAO), Ziming Wang (BNU), on behalf of the SVOM/ ECLAIRs & MXT team report: Using the full X band dataset a corrected ECLAIRs position could be derived for GRB 260726A/sb27062614 (Liang et al., GCN 45219). The improved ECLAIRs position is RA=356.770, Dec=52.851 with a 90% c.l. of 3.7 arcmin. The burst appeared very close to the Earth limb and only part of the burst signal was considered by the onboard processing, explaining the localization error. SVOM MXT observed the ECLAIRs error region starting at T0 = 2026-07-26T23:47:09 (106s after trigger time ECLAIRs T0). Using the full X band dataset, a faint fading source is recovered in the first orbit. Removing the first 150s affected by straylight, the best position is RA=356.903, Dec=52.870 corresponding to: RA (J2000) = 23h47m36.59s. Dec (J2000) = +52d52m11.7s with a statistical 90% C.L. radius of 75.4”. This detection remains tentative due to the presence of straylight possibly remaining in the MXT data. This position is 4.95 arcmin from the ECLAIRs position. This position corrects and supersedes the one reported by (Liang et al., GCN 45219). The Space 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. MXT was developed jointly by CEA, CNES, University of Leicester, IJCLab and MPE. ECLAIRs was developed jointly by CNES, IRAP, APC and CEA. The Burst Advocate (BA) on shift for this burst is Rui-Zhi Li: liruizhi@ynao.ac.cn . Please contact the BA by email if you require additional information regarding the SVOM follow-up of this burst. View this GCN Circular online at https://gcn.nasa.gov/circulars/45229. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0LW...