A. V. Penacchioni, 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),
S. Nakahira (RIKEN), 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), P. S. Marrocchesi (U of Siena)
and the CALET collaboration:
The MAXI GRB 180923A (Maruyama et al., GCN Circ. 23257) was detected
in ground analysis of the CALET Gamma-ray Burst Monitor (CGBM) data
near the MAXI/GSC trigger time at T0=04:08:25 UT on 23 September 2018.
The burst signal was seen by all CGBM detectors.
The burst light curve shows a multi-peaked structure which starts
at T-18 sec and ends at T+107 sec.
The T90 and the T50 durations measured by the SGM data are
122 +- 15 sec and 95 +- 58 sec (40-1000 keV), respectively.
The significant emission is seen only below ~100 keV.
The ground processed light curve is available at
The CALET data used in this analysis are provided by
the Waseda CALET Operation Center located at the Waseda University.