TITLE: GCN CIRCULAR NUMBER: 42634 SUBJECT: GRB 251105B: Insight-HXMT/HE detection DATE: 25/11/10 08:51:03 GMT FROM: renyz16607@163.com Yang-Zhao Ren, Chen-Wei Wang, Cheng-Kui Li, Shao-Lin Xiong, and Chao Zheng (IHEP) report on behalf of the Insight-HXMT team: At 2025-11-05T00:58:34.700 (T0), Insight-HXMT/HE detected a short-duration GRB with extended emission, GRB 251105B, which is also detected by SVOM/GRM (Wang et al., GCN#42586), Fermi/GBM (Fermi GBM team, GCN #42589), and AstroSat/CZTI (Harsha et al., GCN#42591). The Insight-HXMT/HE light curve mainly consists of a narrow, hard spike followed by a long pulse with a T90 of 39.7 +7.9/-2.1 s. The 1s peak rate, measured from T0-0.34 s, is 2439 cnts/sec. Insight-HXMT/HE detected a total of 22413 counts from this burst. The Insight-HXMT /HE light curve can be found here: https://www.bursthub.cn//admin/static/hxmtgrb251105B.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://www.hxmt.org View this GCN Circular online at https://gcn.nasa.gov/circulars/42634. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0LW...