TITLE:   GCN CIRCULAR
NUMBER:  44374
SUBJECT: GRB 260418A: Insight-HXMT/HE detection
DATE:    26/04/21 10:34:05 GMT
FROM:    xueyuan zao <zaoxueyuan@gmail.com>

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 2026-04-18T04:49:35.000 (T0), Insight-HXMT/HE detected a short burst, GRB 260418A, which is also detected by Fermi/GBM (Fermi GBM Team, GCN #44335).

The Insight-HXMT/HE light curve mainly consists of a single pulse with a duration (T90) of 0.30 +0.55/-0.10 s. The 1s peak rate, measured from T0-0.475 s, is 361 cnts/sec. Insight-HXMT/HE detected a total of 292 counts from this burst.

The Insight-HXMT /HE light curve can be found here:
https://www.bursthub.cn//admin/static/hxmtgrb260418A.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/