[vsnet-grb-info 19430] GRB 170511A CALET Gamma-Ray Burst Monitor detection

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  21146
SUBJECT: GRB 170511A CALET Gamma-Ray Burst Monitor detection
DATE:    17/05/26 08:50:40 GMT
FROM:    Takanori Sakamoto at AGU  <tsakamoto at phys.aoyama.ac.jp>

K. Yamaoka (Nagoya U), A. Yoshida, T. Sakamoto, 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 170511A (Takao et al., GCN Circ. 21137;
Fermi-GBM trigger #516175156) was detected by the CALET
Gamma-ray Burst Monitor (CGBM).  The burst signal was only seen
by the SGM instrument.  Since the detection significance is less than
7 sigma in the CGBM data, no on-board trigger occurred for this event.

The light curve of the SGM shows two separated peaks.  The initial peak
starts at T+25 sec, peaks at T+28 sec and ends at T+33 sec (T is the trigger
time of Fermi-GBM).  The second peak starts at T+35 sec, peaks at T+38 sec
and ends at T+40 sec.  The T90 duration measured by the SGM data is
12.5 +- 1.0 sec (40-1000 keV).

The light curve is available at

http://cgbm.calet.jp/cgbm_trigger/flight/1178517128/

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