GRB 230913A: CALET Gamma-Ray Burst Monitor detection

The long GRB 230913A (Fermi GBM Final Real-time Localization: Fermi GBM team, GCN Circ. 34680; Swift/BAT-GUANO arcminute localization, Ronchini et al., GCN Circ. 34683; Fermi GBM Observation: Dalessi et al., GCN Circ. 34689; Glowbug gamma-ray detection: Kerr et al., GCN Circ. 34696) triggered the CALET Gamma-ray Burst Monitor (CGBM) at 07:56:11.95 UTC on 13 September 2023 (http://cgbm.calet.jp/cgbm_trigger/flight/1378626813/index.html). The burst signal was seen by all CGBM detectors. The burst light curve shows a single pulse that starts at T+0.9 sec, peaks at T+1.5 sec, and ends at T+4.4 sec. The T90 and T50 durations measured by the SGM data are 3.1 +/- 0.3 sec and 1.9 +/- 0.4 sec (40-1000 keV), respectively. The ground-processed light curve is available at http://cgbm.calet.jp/cgbm_trigger/ground/1378626813/ The CALET data used in this analysis are provided by the Waseda CALET Operation Center located at Waseda University.