TITLE: GCN CIRCULAR NUMBER: 41827 SUBJECT: GRB 250911A: Insight-HXMT detection DATE: 25/09/13 18:17:46 GMT FROM: Chenwei Wang at IHEP <cwwang@ihep.ac.cn> Chen-Wei Wang, Jin-Peng Zhang, Shao-Lin Xiong, and Chao Zheng report on behalf of the Insight-HXMT team: At 2025-09-11T01:29:28.250 (T0), Insight-HXMT/HE detected the burst GRB 250911A, which is also detected by Swift/BAT (Palmer et al., GCN 41781) and GECAM-B (Zhang et al., GCN#41813. The Insight-HXMT/HE light curve mainly consists of multi-pulses with a T90 of 24.5 +2.5/-1.5 s. The 1s peak rate, measured from T0+5.250 s, is 1857 cnts/sec. The total counts from this burst is 11720 counts. The HXMT/HE light curve can be found here: https://www.bursthub.cn//admin/static/hxmtgrb250911A.png All measurements above are made with the CsI detectors operating in the regular mode with the energy range of about 60-900 keV (deposited energy). Only gamma-rays with energy greater than about 200 keV can penetrate the spacecraft and leave signals in the CsI detectors installed inside of the telescope. Insight-HXMT is the first Chinese space X-ray telescope, which was funded jointly by the China National Space Administration (CNSA) and the Chinese Academy of Sciences (CAS). More information about it could be found at: http://www.hxmt.org. View this GCN Circular online at https://gcn.nasa.gov/circulars/41827. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0LW...