TITLE:   GCN CIRCULAR
NUMBER:  20294
SUBJECT: GRB 161218A: CALET Gamma-Ray Burst Monitor detection
DATE:    16/12/19 13:57:59 GMT
FROM:    Takanori Sakamoto at AGU  <tsakamoto@phys.aoyama.ac.jp>

S. Torii (Waseda U), A. Yoshida, T. Sakamoto, Y. Kawakubo,
M. Moriyama, Y. Yamada (AGU), K. Yamaoka (Nagoya U),
S. Nakahira (JAXA), I. Takahashi (IPMU), Y. Asaoka, S. Ozawa (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 long-duration GRB 161218A (D'Ai et al., GCN Circ. 20283) triggered
the CALET Gamma-ray Burst Monitor (CGBM) at 03:47:31.89 on 18 December 2016.
No real time CGBM GCN notice was distributed about this trigger because the real time
communication from the ISS was off (loss of signal) between 3:43 and 3:52.
The burst signal was seen by all CGBM instruments.

The light curve of the SGM shows a FRED-like structure starting at T+3 sec,
peaking at T+5 sec and ending at T+10 sec.  The T90 duration measured by
the SGM data is 5.1 +- 0.2 sec (40-1000 keV).

The light curve is available at

http://cgbm.calet.jp/cgbm_trigger/flight/1166067870/

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