GCN Circular 22964

Y. Shimizu (Kanagawa U), 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),
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 short GRB 180716A (Konus-Wind trigger time on 19:27:20.845 UT)
triggered the CALET Gamma-ray Burst Monitor (CGBM) at 19:27:24.372 UTC
on 16 July 2018. This GRB is also clearly seen by the publicly available
INTEGRAL SPI-ACS light curve.
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 signal was seen only by the SGM instrument.

The burst light curve shows a structured pulse which starts
at T-0.38 sec, peaks at T-0.13 sec, and ends at T+0.26 sec.
There is a weaker pulse marginally seen at ~T-0.9 sec.
The T90 and the T50 durations measured by the SGM data are
0.58 +- 0.18 sec and 0.26 +- 0.18 sec (40-1000 keV), respectively.

The ground processed light curve is available at

http://cgbm.calet.jp/cgbm_trigger/ground/1215804335/

The CALET data used in this analysis are provided by the Waseda CALET
Operation Center located at the Waseda University.