TITLE: GCN CIRCULAR NUMBER: 27688 SUBJECT: Insight-HXMT detection of a short bright burst from SGR 1935+2154 DATE: 20/05/04 14:38:05 GMT FROM: Shaolin Xiong at IHEP Li X.-B., Li C.-K., Xue W.-C., Ge M.-Y., Xiong S.-L., Jia S.-M., Nie J.-Y., Zhao H.-S., Li B., Lu F.-J., Song L.-M., Liu C.-Z., Chen Y., Cao X.-L., Xu Y.-P., Li T.-P.,  Zhang S.-N.(IHEP), Lin L. (BNU), Zhang B. (UNLV), on behalf of the Insight-HXMT team: During the ToO observation to SGR 1935+2154, Insight-HXMT/HE detected a short (~0.2 s) and bright burst at 2020-05-03 23:25:13.4 UT (satellite time), which was also detected by Fermi/GBM (trigNum 610241118) and AGILE (GCN #27687). According to the relative rates in 17 detectors of HE (20-250 keV), this burst is consistent as from SGR 1935+2154. The HE light curve consists of two major bumps with a separation time of ~50 ms, and a relatively weaker but narrower peak, which is similar to the FRB-associated burst at 14:34:24.5 UT of April 28 (GCN 27675, Atel #13687, Atel #13696) but with a much higher peak flux. The HE light curves have been corrected for data saturation caused by the extreme brightness of this burst in HE. HE detectors are divided into 3 groups, i.e. PDAU 0, PDAU 1 and PDAU 2. Each group consists of 6 detectors and has implemented data saturation correction separately. The Insight-HXMT/HE light curve could be found at: http://newshxmt.ihep.ac.cn/images/grb/SGR1935_20200503T23.png After receiving the ME (5-30 keV) and LE (1-10 keV) data, more analysis results will be reported.