TITLE: GCN CIRCULAR NUMBER: 22361 SUBJECT: GRB 180116A CALET Gamma-Ray Burst Monitor detection DATE: 18/01/18 14:31:46 GMT FROM: Takanori Sakamoto at AGU Y. Shimizu (Kanagawa U), A. Yoshida, T. Sakamoto, V. Pal'shin, Y. Kawakubo, M. Moriyama, Y. Yamada, A. Tezuka, S. Matsukawa (AGU), K. Yamaoka (Nagoya U), S. Nakahira (RIKEN), 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), A. V. Penacchioni, P. S. Marrocchesi (U of Siena) and the CALET collaboration: The long-duration, soft and weak GRB 180116A (Kawai et al., GCN circ. 22347; Stanbro et al., GCN circ. 22356) was detected by the CALET Gamma-ray Burst Monitor (CGBM) in the survey mode. The burst signal is only seen below 100 keV in all CGBM instruments, confirming its soft nature. The light curve of the HXM shows several overlapping pulses. The emission starts at T-5 sec, peaks at T+11 sec and ends at T+47 sec, where T0 is the Fermi-GBM trigger time at 00:36:52.81 UT. The T90 and the T50 durations measured by the combined HXM data (HXM1+HXM2) are 46 +- 10 sec and 27 +- 10 sec (10-300 keV), respectively. The ground processed light curve is available at http://cgbm.calet.jp/cgbm_trigger/ground/1200098002/ The CALET data used in this analysis are provided by the Waseda CALET Operation Center located at the Waseda University.