TITLE: GCN CIRCULAR NUMBER: 30544 SUBJECT: GRB 210727A: CALET Gamma-Ray Burst Monitor detection DATE: 21/07/29 10:11:54 GMT FROM: Valentin Pal'shin at AGU Y. Akaike (Waseda U), A. Yoshida, T. Sakamoto, V. Pal'shin, S. Sugita (AGU), Y. Kawakubo (LSU), K. Yamaoka (Nagoya U), S. Nakahira (RIKEN), Y. Asaoka (ICRR), S. Torii, 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 210727A (BALROG localization: Biltzinger et al., GCN Circ. 30531; AGILE/MCAL detection: Ursi et al., GCN Circ. 30533; IPN triangulation: Ridnaia et al., GCN Circ. 30541; https://gcn.gsfc.nasa.gov/other/210727A.gcn3) triggered the CALET Gamma-ray Burst Monitor (CGBM) at 09:50:46.605 UTC on 27 July 2021. The burst signal was seen by all CGBM detectors. The burst light curve shows a multi-peaked structure which starts at T-0.38 sec and ends at T+0.64 sec. The T90 and T50 durations measured by the SGM data are 0.96 +- 0.14 sec and 0.51 +- 0.09 sec (40-1000 keV), respectively. The ground processed light curve is available at http://cgbm.calet.jp/cgbm_trigger/ground/1311414395/ The CALET data used in this analysis are provided by the Waseda CALET Operation Center located at the Waseda University.