TITLE: GCN CIRCULAR NUMBER: 27896 SUBJECT: GRB 200530A: CALET Gamma-Ray Burst Monitor detection DATE: 20/06/06 12:01:09 GMT FROM: Valentin Pal'shin at AGU S. Sugita, A. Yoshida, T. Sakamoto, V. Pal'shin (AGU), Y. Kawakubo (LSU), K. Yamaoka (Nagoya U), S. Nakahira (RIKEN), 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: The long GRB 200530A (Fermi GBM Localization: the Fermi GBM team, GCN Circ. 27861; AstroSat CZTI detection: Gupta et al., GCN Circ. 27864; Fermi-LAT detection: Longo et al., GCN Circ. 27891; https://gcn.gsfc.nasa.gov/other/200530A.gcn3) triggered the CALET Gamma-ray Burst Monitor (CGBM) at 00:44:15.067 UTC on 30 May 2020. The burst signal was seen by all CGBM detectors. Because of a problem in one of the ground alert processing script, the GCN notice was not distributed automatically for this event. The burst light curve shows a multi-peaked structure which starts at T-2.9 sec, peaks at T+5.6 sec and ends at T+21.1 sec. The T90 and T50 durations measured by the SGM data are 19.7 +- 2.0 sec and 9.5 +- 0.9 sec (40-1000 keV), respectively. The ground processed light curve is available at http://cgbm.calet.jp/cgbm_trigger/ground/1274834660/ The CALET data used in this analysis are provided by the Waseda CALET Operation Center located at the Waseda University.