TITLE: GCN CIRCULAR NUMBER: 27974 SUBJECT: GRB 200615B: CALET Gamma-Ray Burst Monitor detection DATE: 20/06/17 12:04:33 GMT FROM: Valentin Pal'shin at AGU S. Nakahira (RIKEN), A. Yoshida, T. Sakamoto, V. Pal'shin, S. Sugita (AGU), Y. Kawakubo (LSU), K. Yamaoka (Nagoya U), Y. Asaoka, S. Torii (Waseda U), Y. Shimizu, T. Tamura (Kanagawa U), N. Cannady (GSFC/UMBC), M. L. Cherry (LSU), S. Ricciarini (U of Florence), P. S. Marrocchesi (U of Siena), and the CALET collaboration: At 10:26:46.325 UTC on 15 June 2020, the CALET Gamma-ray Burst Monitor (CGBM) triggered on the long weak GRB 200615B (trigger 1276251981: http://cgbm.calet.jp/cgbm_trigger/flight/1276251981/index.html), which was also detected by the MAXI/GSC at T0(CGBM)+213 sec (Miike et al. 2020, GCN Circ. 27960). The burst signal was seen by all CGBM detectors. The burst light curve shows a multi-peaked structure which starts at T+3.8 sec and ends at T+48.8 sec. The T90 and T50 durations measured by the SGM data are 40.0 +- 6.3 sec and 28.0 +- 9.5 sec (40-1000 keV), respectively. The ground processed light curve is available at http://cgbm.calet.jp/cgbm_trigger/ground/1276251981/ The CALET data used in this analysis are provided by the Waseda CALET Operation Center located at the Waseda University.