GCN Circular 41457

Chen-Wei Wang, Wen-Jun Tan, Yue Huang, Shao-Lin Xiong, and Chao Zheng report on behalf of the Insight-HXMT team:

At 2025-08-19T17:49:46.000 (T0), Insight-HXMT/HE detected an intermedium duration burst GRB 250819A.

The Insight-HXMT/HE light curve mainly consists of multi-pulses with a T90 of 7.5 +3.2/-2.9 s. The 1s peak rate, measured from T0-0.25 s, is 1153 cnts/sec. The total counts from this burst is 4769 counts.

The HXMT/HE light curve can be found here:
https://www.bursthub.cn//admin/static/hxmtgrb250819A.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.or