TITLE: GCN CIRCULAR NUMBER: 22450 SUBJECT: GRB 180210A: Insight-HXMT/HE observation DATE: 18/02/26 02:59:43 GMT FROM: Xuefeng Lu at IHEP X. F. Lu, J. Y. Liao, C. K. Li, Y. Huang, Y. Zhu, S. L. Xiong, X. B. Li, C. Z. Liu, Z. W. Li, J. L. Zhao, Y. F. Zhang, X.F. Li, Z. Chang, Y. J. Jin, C. L. Zou (IHEP), A. M. Zhang, Z. Zhang (THU), T. P. Li (IHEP/THU), F. J. Lu, L. M. Song, H. Y. Wang, M. Wu, Y. P. Xu, S. N. Zhang (IHEP), report on behalf of the Insight-HXMT team: At 2018-02-10T12:24:38.55 UT, the Insight-HXMT/HE detected GRB 180210A(trigger ID: HEB180210517) in a routine search of the data, which was also triggered by Fermi/GBM(GCN Circ. 22407),Fermi/LAT(GCN Circ. 22408), Swift/XRT(GCN Circ. 22413) and KONUS-Wind(GCN Circ. 22415). The Insight-HXMT/HE light curve consists of a multi-peaked pulse with a duration (T90) of 26.7 s measured from T0+3.9 s. The 1-s peak rate, measured from T0+23.9 s, is 3173.8 cnts/sec. The total counts from this burst is 40447.9 counts. URL_LC: http://www.hxmt.org/images/GRB/HEB180210517_lc.jpg 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. The time-averaged spectrum from T0-8 to T0+30 s is adequately fit by a Power Law model with spectral index = -1.86 +/- 0.03. The energy fluence is (4.5 +/- 0.2) E-05 erg/cm^2 in 200 - 5000 keV in this time interval. The analysis results presented above are preliminary, final results will be published elsewhere. 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/index.php/enhome. [GCN OPS NOTE(26feb18): "2018-02-10T17:29:06.000" was changed to "2018-02-10T12:24:38.55" and "HEB180210728" was changed to "HEB180210517".]