//////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 21002 SUBJECT: GRB 170403B CALET Gamma-Ray Burst Monitor detection DATE: 17/04/08 01:07:38 GMT FROM: Takanori Sakamoto at AGU Y. Kawakubo, A. Yoshida, T. Sakamoto, M. Moriyama, Y. Yamada (AGU), K. Yamaoka (Nagoya U), S. Nakahira (RIKEN), I. Takahashi (IPMU), Y. Asaoka, S. Ozawa, S. Torii (Waseda U), Y. Shimizu, T. Tamura (Kanagawa U), W. Ishizaki (ICRR), M. L. Cherry (LSU), S. Ricciarini (U of Florence), A. V. Penacchioni, P. S. Marrocchesi (U of Siena) and the CALET collaboration: The long-duration GRB 170403B (Fermi GBM trigger #512931458; INTEGRAL SPI-ACS trigger #7799; Konus-Wind trigger time on 16:57:35.034) triggered the CALET Gamma-ray Burst Monitor (CGBM) at 16:57:31.18 on 3 April 2017. The burst signal was only seen by the SGM instrument. The light curve of the SGM shows a single peak starting at T0+2 sec, peaking at T+5 sec and ending at T+10 sec. The T90 duration measured by the SGM data is 6.7 +- 0.4 sec (40-1000 keV). The light curve is available at http://cgbm.calet.jp/cgbm_trigger/flight/1175273491/ The CALET data used in this analysis are provided by the Waseda CALET Operation Center located at the Waseda University.