TITLE: GCN CIRCULAR NUMBER: 32124 SUBJECT: GRB 220523B: CALET Gamma-Ray Burst Monitor detection DATE: 22/05/26 14:42:39 GMT FROM: Yuta Kawakubo at Louisiana State U./CALET S. Sugita, A. Yoshida, T. Sakamoto(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 long GRB 220523B (Fermi GBM Detection: Fermi GBM team, GCN Circ. 32098) triggered the CALET Gamma-ray Burst Monitor (CGBM) at 13:24:04.522 UTC on 23 May 2022 (http://cgbm.calet.jp/cgbm_trigger/flight/1337347281/index.html). The burst signal was seen by all CGBM detectors. The burst light curve shows a multi-peaked structure which starts at T+3.1 sec, peaks at T+5.7 sec, and ends at T+10.1 sec. The T90 and T50 durations measured by the SGM data are 5.9 +/- 0.5 sec and 2.1 +/- 0.3 sec (40-1000 keV), respectively. The ground processed light curve is available at http://cgbm.calet.jp/cgbm_trigger/ground/1337347281/ The CALET data used in this analysis are provided by the Waseda CALET Operation Center located at the Waseda University.