TITLE: GCN CIRCULAR NUMBER: 27584 SUBJECT: GRB 200410A: CALET Gamma-Ray Burst Monitor detection DATE: 20/04/15 12:20:30 GMT FROM: Valentin Pal'shin at AGU N. Cannady (GSFC/UMBC), A. Yoshida, T. Sakamoto, V. Pal'shin, S. Sugita (AGU), Y. Kawakubo (LSU), K. Yamaoka (Nagoya U), S. Nakahira (RIKEN), Y. Asaoka, 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 Swift GRB 200410A (Simpson et al., GCN Circ. 27518, Laha et al., GCN Circ. 27578; https://gcn.gsfc.nasa.gov/other/200410A.gcn3) triggered the CALET Gamma-ray Burst Monitor (CGBM) at 02:25:15.105 UTC on 10 April 2020. The burst signal was seen by the SGM detector. No real-time CGBM GCN notice was distributed about this trigger because the real-time communication from the ISS was off (loss of signal). The burst light curve shows a weak pulse which starts at T-3.9 sec, peaks at T-1.0 sec and ends at T+2.4 sec. The T90 and T50 durations measured by the SGM data are 5.5 +- 2.2 sec and 2 +- 2 sec (40-1000 keV), respectively. The ground processed light curve is available at http://cgbm.calet.jp/cgbm_trigger/ground/1270520355/ The CALET data used in this analysis are provided by the Waseda CALET Operation Center located at the Waseda University.