TITLE: GCN CIRCULAR NUMBER: 20483 SUBJECT: GRB 170115B: CALET Gamma-Ray Burst Monitor detection DATE: 17/01/19 04:50:32 GMT FROM: Takanori Sakamoto at AGU Y. Shimizu (Kanagawa U), A. Yoshida, T. Sakamoto, Y. Kawakubo, M. Moriyama, Y. Yamada (AGU), K. Yamaoka (Nagoya U), S. Nakahira (JAXA), I. Takahashi (IPMU), Y. Asaoka, S. Ozawa, S. Torii (Waseda U), T. Tamura (Kanagawa U), W. Ishizaki (ICRR), M. L. Cherry (LSU), S. Ricciarini (U of Florence), P. S. Marrocchesi (U of Siena) and the CALET collaboration: The long-duration GRB 170115B (Hamburg et al., GCN Circ. 20463; McEnery et al., GCN Circ. 20464; Sharma et al., GCN Circ. 20466; Xiao et al., GCN Circ. 20469; Verrecchia et al., GCN Circ. 20474; Frederiks et al., GCN Circ. 20476) triggered the CALET Gamma-ray Burst Monitor (CGBM) at 17:49:12.63 on 15 January 2017. The burst signal was only seen by the SGM instrument. The light curve of the SGM shows several overlapping pulses starting at T0, peaking at T+3 sec and ending at T+15 sec. The T90 duration measured by the SGM data is 12.0 +- 0.9 sec (40-1000 keV). The light curve is available at http://cgbm.calet.jp/cgbm_trigger/flight/1168537525/ The CALET data used in this analysis are provided by the Waseda CALET Operation Center located at the Waseda University.