TITLE: GCN CIRCULAR NUMBER: 20556 SUBJECT: GRB 170124A: CALET Gamma-Ray Burst Monitor detection DATE: 17/01/28 04:30:56 GMT FROM: Takanori Sakamoto at AGU W. Ishizaki (ICRR), 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), Y. Shimizu, T. Tamura (Kanagawa U), M. L. Cherry (LSU), S. Ricciarini (U of Florence), P. S. Marrocchesi (U of Siena) and the CALET collaboration: The long-duration GRB 170124A (Fermi-GBM trigger #506984291; Konus-Wind trigger time on 20:58:06.428 UT) triggered the CALET Gamma-ray Burst Monitor (CGBM) at 20:58:04.58 on 24 January 2017. The burst signal was seen by all CGBM instruments. The light curve of the SGM shows two peaks. The first peak starts at T0, peaks at T+8 sec and ends at T+15 sec. The second peak starts at T+15 sec, peaks at T+23 sec and ends at T+30 sec. The T90 duration measured by the SGM data is 20.9 +- 1.3 sec (40-1000 keV). The light curve is available at http://cgbm.calet.jp/cgbm_trigger/flight//1169326441/index.html The CALET data used in this analysis are provided by the Waseda CALET Operation Center located at the Waseda University.