TITLE:   GCN CIRCULAR
NUMBER:  26240
SUBJECT: GRB 191031D: CALET Gamma-Ray Burst Monitor detection
DATE:    19/11/13 03:39:09 GMT
FROM:    Valentin Pal'shin at AGU  <val@phys.aoyama.ac.jp>

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. 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 short bright GRB 191031D (Swift detection: Ambrosi et al.,
GCN Circ. 26112, Sakamoto et al., GCN Circ. 26133;
Fermi GBM detection: Mailyan and Meegan, GCN Circ. 26118;
AGILE/MCAL observations: Ursi et al., GCN Circ. 26123;
Konus-Wind observation: Frederiks et al., GCN Circ. 26126, 26149;
AstroSat CZTI detection: Gaikwad et al., GCN Circ. 26129;
https://gcn.gsfc.nasa.gov/other/191031D.gcn3)
triggered the CALET Gamma-ray Burst Monitor (CGBM) at 21:23:31.261 UTC
on 31 October 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-peak structure which starts at T-0.168
sec, peaks at 0.008 sec and ends at T+0.192 sec. The T90 and T50 durations
measured by the SGM data are 0.240 +- 0.079 sec and 0.104 +- 0.008 sec
(40-1000 keV), respectively.

The ground processed light curve is available at

http://cgbm.calet.jp/cgbm_trigger/ground/1256592147/

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