TITLE: GCN CIRCULAR NUMBER: 35272 SUBJECT: GRB 231204A: CALET Gamma-Ray Burst Monitor detection DATE: 23/12/05 19:10:01 GMT FROM: Yuta Kawakubo at Louisiana State University <kawakubo1@lsu.edu> T. Tamura (Kanagawa U), A. Yoshida, T. Sakamoto, S. Sugita (AGU), Y. Kawakubo (LSU), K. Yamaoka (Nagoya U), S. Nakahira (JAXA), Y. Asaoka (ICRR), S. Torii, Y. Akaike, K. Kobayashi (Waseda U), Y. Shimizu (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 231204A (Fermi GBM Final Real-time Localization: Fermi GBM team, GCN Circ. 35258; AstroSat CZTI detection: Waratkar et al., GCN Circ. 35267) triggered the CALET Gamma-ray Burst Monitor (CGBM) at 20:00:00.75 UTC on 4 December 2023 (http://cgbm.calet.jp/cgbm_trigger/flight/1385755095/). The burst signal was seen by only the SGM detector. The burst light curve shows a weak pulse that starts at T+3.1 sec, peaks at T+4.1 sec, and ends at T+7.9 sec. The T90 and T50 durations measured by the SGM data are 4.5 +/- 0.5 sec and 2.5 +/- 0.1 sec (40-1000 keV), respectively. The ground-processed light curve is available at http://cgbm.calet.jp/cgbm_trigger/ground/1385755095/index.html The CALET data used in this analysis are provided by the Waseda CALET Operation Center located at Waseda University. View this GCN Circular online at https://gcn.nasa.gov/circulars/35272. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0LW...