TITLE: GCN CIRCULAR NUMBER: 23934 SUBJECT: GRB 190305A: Insight-HXMT/HE detection DATE: 19/03/06 14:59:08 GMT FROM: Shuo Xiao at IHEP S. Xiao, C. K. Li, X. B. Li, G. Li, J. Y. Liao, S. L. Xiong, C. Z. Liu, X. F. Li, Z. W. Li, Z. Chang, X. F. Lu, A. M. Zhang, Y. F. Zhang, 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 2019-03-05T13:05:19.000 (T0), the Insight-HXMT/HE detected GRB 190305A (trigger ID: HEB190305545) in a routine search of the data, which was also triggered by AGILE/MCAL (Ursi et al., GCN23930), CALET/CGBM and MAXI/GSC (Nakahira et al., GCN23933). The Insight-HXMT/HE light curve mainly consists of multiple pulses with a duration (T90) of 1.35 s measured from T0+0.45 s. The 1-s peak rate, measured from T0+1.51 s, is 22 cnts/ms. The total counts from this burst is 23194 counts. URL_LC: http://www.hxmt.org/images/GRB/HEB190305545_lc.jpg This light curve has not been corrected for the data loss, which was caused by the extreme brightness of this burst. All measurements above are made with the CsI detectors operating in the regular mode with the energy range of about 80-800 keV (record 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 could be found at: http://www.hxmt.org.