TITLE:   GCN CIRCULAR
NUMBER:  45408
SUBJECT: GRB 260818B: Insight-HXMT detection
DATE:    26/08/20 05:32:14 GMT
FROM:    Chenwei Wang at IHEP <cwwang@ihep.ac.cn>

Chen-Wei Wang, Yang-Zhao Ren, Shao-Lin Xiong, Cheng-Kui Li, and Chao Zheng report on behalf of the Insight-HXMT team:

At 2026-08-18T20:11:12.600 (T0), Insight-HXMT/HE detected the short burst GRB 260818B, which is also detected by SVOM/ECLAIRs (Bertrand Cordier et al., GCN#45398) and SVOM/GRM.
The Insight-HXMT/HE light curve mainly consists of a narrow pulse with a T90 of 0.15 +0.15/-0.10 s. 

The HXMT/HE light curve can be found here:
https://www.bursthub.cn/gcn/2026/hxmtgrb260818B.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.