GCN Circular 29346

W. C. Xue, C. Cai, J. C. Liu, Q. Luo, S. Xiao, 
Q. B. Yi, Y. Q. Zhang, C. Zheng, Y. Huang, C. K. Li, 
G. Li, X. B. Li, J. Y. Liao, X. Y. Song, S. L. Xiong, C. Z. Liu, 
X. F. Li, Z. W. Li, Z. Chang, A. M. Zhang, Y. F. Zhang, 
X. F. Lu, C. L. Zou (IHEP), Y. J. Jin, Z. Zhang (THU), 
T. P. Li (IHEP/THU), F. J. Lu, L. M. Song, 
M. Wu, Y. P. Xu, S. N. Zhang (IHEP), 
report on behalf of the Insight-HXMT team:

At 2021-01-21T18:41:48.750 (T0), Insight-HXMT/HE detected 
GRB 210121A (trigger ID: HEB210121779) in a routine search of the data.

The Insight-HXMT/HE light curve mainly consists of multiple
pulses with a duration (T90) of 13.24 s measured from T0+0.27 s. 
The 1-ms peak rate, measured from T0+0.52 s, is 10996 cnts/sec. 
The total counts from this burst is 45848 counts. 
URL_LC: http://twiki.ihep.ac.cn/pub/HXMT/GRBList/HEB210121779_lc.jpg

All measurements above are made with the CsI detectors operating in the 
GRB mode with the energy range of about 80-800 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.