GCN Circular 42970
Subject
EP251202a / GRB 251202A: Insight-HXMT/HE detection
Event
Date
2025-12-03T13:45:08Z (15 days ago)
From
guohx@ihep.ac.cn
Via
Web form
Hao-Xuan Guo, Chen-Wei Wang, Chao Zheng, and Shao-Lin Xiong (IHEP) report on behalf of the Insight-HXMT team:
At 2025-12-02T01:50:52.000 (T0), Insight-HXMT/HE detected a long GRB EP251202a / GRB 251202A, which is also detected by Fermi/GBM (Fermi GBM Team, GCN #42933 and #42957), Einstein Probe (Einstein Probe (EP) team, GCN #42934, #42937 and #42946) and GOTO (GOTO collaboration, GCN #42947).
The Insight-HXMT/HE light curve mainly consists of multiple pulses with a T90 of 25 +12/-11 s. The 1s peak rate, measured from T0+8.5 s, is 254 cnts/sec. Insight-HXMT/HE detected a total of 2752 counts from this burst.
The Insight-HXMT/HE light curve can be found here:
https://www.bursthub.cn//admin/static/hxmtgrb251202A.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://www.hxmt.org