GCN Circular 44849

Xue-Yuan Zao, Chen-Wei Wang, Cheng-Kui Li, Shao-Lin Xiong, and Chao Zheng (IHEP) report on behalf of the Insight-HXMT team:

At 2026-06-05T01:04:27.850 (T0), Insight-HXMT/HE detected a long burst, GRB 260605A, which is also detected by SVOM/GRM.

The Insight-HXMT/HE light curve mainly consists of a single pulse with a duration (T90) of 11.0 +2.5/-1.0 s. The 1s peak rate, measured from T0+1.75 s, is 6386 cnts/sec. Insight-HXMT/HE detected a total of 22324 counts from this burst.  

The Insight-HXMT /HE light curve can be found here: 
https://www.bursthub.cn//admin/static/hxmtgrb260605A.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/