GCN Circular 22849

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.