//////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 21254 SUBJECT: GRB 170606A CALET Gamma-Ray Burst Monitor detection DATE: 17/06/16 03:45:35 GMT FROM: Takanori Sakamoto at AGU K. Yamaoka (Nagoya U), A. Yoshida, T. Sakamoto, Y. Kawakubo, M. Moriyama, Y. Yamada, A. Tezuka, S. Matsukawa (AGU), 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 170606A (Fermi-GBM trigger #518483662) triggered the CALET Gamma-ray Burst Monitor (CGBM) at 23:14:14.82 on 6 June 2017. The burst signal was seen only by the SGM instrument. The light curve of the SGM shows a single peak. The emission starts at T+3 sec, peaks at T+4.5 sec and ends at T+8 sec. The T90 duration measured by the SGM data is 3.9 +- 0.4 sec (40-1000 keV). The light curve is available at http://cgbm.calet.jp/cgbm_trigger/flight/1180825585/ The CALET data used in this analysis are provided by the Waseda CALET Operation Center located at the Waseda University.