TITLE: GCN CIRCULAR NUMBER: 30158 SUBJECT: GRB 210605A: CALET Gamma-Ray Burst Monitor detection DATE: 21/06/09 10:16:53 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 (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 short GRB 210605A (Fermi GBM Final Real-time Localization: Fermi GBM team, GCN Circ. 30127; IPN localization: Svinkin et al., GCN Circ. 30143; Konus-Wind detection: Frederiks et al., GCN Circ. 30144; https://gcn.gsfc.nasa.gov/other/210605A.gcn3) triggered the CALET Gamma-ray Burst Monitor (CGBM) at 05:08:58.441 UTC on 5 June 2021. The burst signal was seen by all CGBM detectors. 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 multi-peaked pulse which starts at T-0.096 sec, peaks at -0.032 sec and ends at T+0.240 sec. The T90 and T50 durations measured by the SGM data are 0.304 +- 0.051 sec and 0.144 +- 0.045 sec (40-1000 keV), respectively. The ground processed light curve is available at http://cgbm.calet.jp/cgbm_trigger/ground/1306904781/ The CALET data used in this analysis are provided by the Waseda CALET Operation Center located at the Waseda University.