Y. Shimizu (Kanagawa U),
A. Yoshida, T. Sakamoto, V. Pal'shin, S. Sugita (AGU),
Y. Kawakubo (LSU), K. Yamaoka (Nagoya U), S. Nakahira (RIKEN),
Y. Asaoka, S. Ozawa, S. Torii (Waseda U),
T. Tamura (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 190531B (Fermi-LAT detection: Axelsson et al.,GCN Circ. 24701;
Fermi-GBM observations: Veres and Meegan, GCN Circ. 24705;
Insight-HXMT/HE detection: Yi et al., GCN Circ. 24713;
Konus-Wind observation: Svinkin et al., GCN Circ. 24730)
triggered the CALET Gamma-ray Burst Monitor (CGBM) at 20:10:20.034 UTC
on 31 May 2019. 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 multi-peaked emission episode which starts
at T-9.7 sec, peaks at 14.5 sec and ends at T+74.5 sec.
The T90 and T50 durations measured by the SGM data are 36.8 +- 20.0 sec
and 13.5 +- 0.9 sec (40-1000 keV), respectively.
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.