GCN Circular 22285

K. Yamaoka (Nagoya U), A. Yoshida, T. Sakamoto, V. Pal'shin, Y. Kawakubo,
M. Moriyama, Y. Yamada, A. Tezuka, S. Matsukawa (AGU), S. Nakahira (RIKEN),
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-duration GRB 171212C (Konus-Wind trigger time on 22:53:41.759)
triggered the CALET Gamma-ray Burst Monitor (CGBM) at 22:53:37.68 on
12 December 2017.  The burst signal was seen only by the SGM instrument.

The light curve of the SGM shows two weak pulses.  The emission starts
at T0, peaks at T+0.5 sec and ends at T+30 sec.  The T90 duration measured
by the SGM data is 27.2 +- 3.6 sec (40-1000 keV).  The T50 duration measured
by the SGM data is 18.1 +- 4.5 sec (40-1000 keV).

The ground processed light curve is available at

http://cgbm.calet.jp/cgbm_trigger/ground/1197154263/

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

[GCN OPS NOTE(11jan18): Per author's request, the name of the GRB was changed
from 171212A to 171212C.]