TITLE:   GCN CIRCULAR
NUMBER:  44980
SUBJECT: GRB 260616A: Insight-HXMT detection
DATE:    26/06/18 18:19:26 GMT
FROM:    Chenwei Wang at IHEP <cwwang@ihep.ac.cn>

Chen-Wei Wang, Hao-Xuan Guo, Zheng-Hang Yu, Shao-Lin Xiong, Cheng-Kui Li, and Chao Zheng report on behalf of the Insight-HXMT team:

At 2026-06-16T03:22:29.650 (T0), Insight-HXMT/HE detected GRB 260616A, which is also detected by Fermi/GBM (Fermi GBM team, GCN#44948), Fermi/LAT (S. Lopez et al., GCN #44960), GECAM-B (Hao-Xuan Guo et al., GCN #44964), Konus-Wind (A. Ridnaia et al., GCN#44976) and SVOM/GRM.
	
The Insight-HXMT/HE light curve mainly consists of a set of dense spikes with a T90 of 76.0 +4.5/-4.0 s. The 1s peak rate, measured from T0+14.8 s, is 5435 cnts/sec. The total counts from this burst is 178317 counts.

The HXMT/HE light curve can be found here:
https://www.bursthub.cn//admin/static/hxmtgrb260616A.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.