TITLE: GCN CIRCULAR NUMBER: 30117 SUBJECT: GRB 210602A: CALET Gamma-Ray Burst Monitor detection DATE: 21/06/03 07:04:45 GMT FROM: Valentin Pal'shin at AGU V. Pal'shin, A. Yoshida, T. Sakamoto, S. Sugita (AGU), Y. Kawakubo (LSU), K. Yamaoka (Nagoya U), S. Nakahira (RIKEN), Y. Asaoka (ICRR), S. Torii, Y. Akaike, K. Kobayashi (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 bright GRB 210602A (MAXI/GSC detection: Serino et al., GCN Circ. 30113) triggered the CALET Gamma-ray Burst Monitor (CGBM) at 12:04:01.493 UTC on 2 June 2021 (http://cgbm.calet.jp/cgbm_trigger/flight/1306670489/index.html). The burst signal was seen by all CGBM detectors. The burst light curve shows a single pulse which starts at T+0.5 sec, peaks at T+1.4 sec, and ends at T+3.0 sec. The T90 and T50 durations measured by the SGM data are 1.9 +- 0.3 sec and 0.5 +- 0.1 sec (40-1000 keV), respectively. The ground processed light curve is available at http://cgbm.calet.jp/cgbm_trigger/ground/1306670489/ The CALET data used in this analysis are provided by the Waseda CALET Operation Center located at the Waseda University.