[vsnet-grb-info 18417] GRB 160821A: CALET Gamma-Ray Burst Monitor detection

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  19865
SUBJECT: GRB 160821A: CALET Gamma-Ray Burst Monitor detection
DATE:    16/08/26 01:59:26 GMT
FROM:    Takanori Sakamoto at AGU  <tsakamoto at phys.aoyama.ac.jp>

P. S. Marrocchesi (U of Siena), 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, S. Torii (Waseda U),
Y. Shimizu, T. Tamura (Kanagawa U), W. Ishizaki (ICRR),
M. L. Cherry (LSU), S. Ricciarini (U of Florence),
and the CALET collaboration:

The long-duration GRB 160821A (Siegel et al., GCN Circ. 19830;
McEnery et al., GCN Circ. 19831; Stanbro et al., GCN Circ. 19835;
INTEGRAL-SPI/ACS trigger #7537) triggered the CALET Gamma-ray Burst Monitor
(CGBM) at 20:36:21.91 on 21 August 2016.  The burst signal was seen by
all CGBM instruments.  Note that the CGBM trigger time is 111 sec after
the trigger time of Swift/BAT.  This is because the CGBM triggered at the
bright main peak of the burst (Markwardt et al. GCN Circ. 19840).

The light curve of the SGM shows a bright peak with several overlapping
pulses.  The emission starts from T sec, peaks at T+24 sec and ends at
T+80 sec.  There is a hint of the emission in the SGM light curve around
the trigger time of Swift/BAT.  The T90 duration measured by the SGM data
is 35.1 +- 0.8 sec (40-1000 keV).

The light curve is available at

http://cgbm.calet.jp/cgbm_trigger/flight/1155846835/

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