TITLE: GCN CIRCULAR NUMBER: 43591 SUBJECT: GRB 260131A: Insight-HXMT/HE detection DATE: 26/02/01 15:06:33 GMT FROM: Xinghao Luo at IHEP <2952704891@qq.com> Xing-Hao Luo, Chen-Wei Wang, Chao Zheng, Hao-Xuan Guo, Xiao-Bo Li and Shao-Lin Xiong (IHEP) report on behalf of the Insight-HXMT team: At 2026-01-31T06:39:31.400 (T0), Insight-HXMT/HE detected the long burst GRB 260131A, which is also detected by Fermi/GBM (Fermi GBM Team, GCN #43579) . The Insight-HXMT/HE light curve mainly consists of multiple pulses with a T90 of 7.0 +2.5/-1.0 s. The 1s peak rate, measured from T0+1.75 s, is 982 cnts/sec. Insight-HXMT/HE detected a total of 5366 counts form this burst. The HXMT/HE light curve can be found here: https://www.bursthub.cn//admin/static/hxmtgrb260131A.png All measurements above are made with the CsI detectors of Insight-HXMT/HE 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://hxmten.ihep.ac.cn/ View this GCN Circular online at https://gcn.nasa.gov/circulars/43591. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0LW...