TITLE:   GCN CIRCULAR
NUMBER:  45413
SUBJECT: GRB 260820A: Insight-HXMT/HE detection
DATE:    26/08/21 09:35:34 GMT
FROM:    yzh807926@163.com

Zheng-Hang Yu, Chao Zheng, and Shao-Lin Xiong (IHEP) report on behalf of the Insight-HXMT team:

At 2026-08-20T04:24:39.950 (T0), Insight-HXMT/HE detected GRB 260820A, which is also detected by Fermi/GBM (Fermi GBM team, GCN #45409).

The Insight-HXMT/HE light curve mainly consists of a pulse with a T90 of 0.22 +0.19/-0.13 s. The 1 s peak rate, measured from T0-0.15 s, is 707 cnts/sec. Insight-HXMT/HE detected a total of 690 counts from this burst.

The Insight-HXMT/HE light curve can be found here:
https://www.bursthub.cn/gcn/2026/hxmtgrb260820A.png

All measurements above are made with the CsI detectors of Insight-HXMT/HE operating in the Normal 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