TITLE:   GCN CIRCULAR
NUMBER:  21067
SUBJECT: GRB 170428A CALET Gamma-Ray Burst Monitor detection
DATE:    17/05/04 08:47:22 GMT
FROM:    Takanori Sakamoto at AGU  <tsakamoto@phys.aoyama.ac.jp>

Y. Yamada, A. Yoshida, T. Sakamoto, Y. Kawakubo, M. Moriyama,
A. Tezuka, S. Matsukawa (AGU), K. Yamaoka (Nagoya U), 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 short-duration GRB 170428A (Beardmore et al., GCN Circ. 21042; Tsvetkova
et al., GCN Circ. 21045) was detected the CALET Gamma-ray Burst Monitor (CGBM)
by the ground process pipeline at 09:13:42.36 on 28 April 2017 at 5.1 sigma which
is below the trigger threshold of the on-board trigger.  The burst signal was seen
only by the SGM instrument.

Because there was no on-board trigger, no event data were stored for this
event.  The continuous light curve data recorded in 0.125 s time resolution are
not fine enough to investigate the temporal structure and the duration of this event.

The light curve is available at

http://cgbm.calet.jp/cgbm_trigger/flight/1177405621/

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