TITLE: GCN CIRCULAR NUMBER: 22849 SUBJECT: GRB 180623B: CALET Gamma-Ray Burst Monitor detection DATE: 18/06/26 06:05:31 GMT FROM: Takanori Sakamoto at AGU S. Nakahira (RIKEN), A. Yoshida, T. Sakamoto, V. Pal'shin, S. Sugita, Y. Kawakubo, A. Tezuka, S. Matsukawa, H. Onozawa, T. Ito, H. Morita, Y. Sone (AGU), K. Yamaoka (Nagoya U), I. Takahashi (IPMU), Y. Asaoka, S. Ozawa, S. Torii (Waseda U), Y. Shimizu, T. Tamura (Kanagawa U), W. Ishizaki (ICRR), M. L. Cherry (LSU), S. Ricciarini (U of Florence), A. V. Penacchioni, P. S. Marrocchesi (U of Siena) and the CALET collaboration: The long GRB 180623B (Fermi-GBM trigger #551478155; INTEGRAL SPI-ACS trigger #8082; Konus-Wind trigger time on 20:22:36.97) triggered the CALET Gamma-ray Burst Monitor (CGBM) at 20:22:36.598 UTC on 23 June 2018. 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 single pulse which starts at T-3.5 sec, peaks at T+4.5 sec and ends at T+11.6 sec. The T90 and the T50 durations measured by the SGM data are 12.0 +- 1.1 sec and 5.1 +- 0.5 sec (40-1000 keV), respectively. The ground processed light curve is available at http://cgbm.calet.jp/cgbm_trigger/ground/1213820487 The CALET data used in this analysis are provided by the Waseda CALET Operation Center located at the Waseda University.