[vsnet-grb-info 17243] GRB 151107B: CALET Gamma-Ray Burst Monitor detection

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  18605
SUBJECT: GRB 151107B: CALET Gamma-Ray Burst Monitor detection
DATE:    15/11/15 00:45:59 GMT
FROM:    Takanori Sakamoto at AGU  <tsakamoto at phys.aoyama.ac.jp>

A. Yoshida, T. Sakamoto, I. Takahashi, Y. Kawakubo, K. Senuma, 
M. Moriyama, Y. Yamada (AGU), K. Yamaoka (Nagoya U), S. Nakahira (JAXA), 
Y. Asaoka, S. Ozawa, S. Torii (Waseda U), Y. Shimizu, T. Tamura (Kanagawa U), 
M. L. Cherry (LSU), S. Ricciarini (U of Florence), P. S. Marrocchesi (U of Siena) 
and the CALET collaboration:

The long-duration GRB 151107B (Stanbro et al. GCN Circ. 18570) triggered the CALET 
Gamma-Ray Burst Monitor (CGBM) at 20:24:54.77 UT on 7 November 2015.  The burst 
was detected by all three CGBM instruments.  Based on the signal-to-noise among the 
instruments, the incident angle of the burst was estimated as ~40-70 deg from the zenith 
direction of CGBM.  This estimated incident angle is roughly consistent with the IPN 
triangulation (Hurley et al., GCN Circ. 18577).

The light curve of the Soft Gamma-ray Monitor (SGM; 30 keV - 20 MeV) shows the main 
peak starting from T0-5 sec, peaking at T0+5 sec and ending at T0+~30 sec.  The 
second weak peak starts from T0+90 sec, peaks at T0+95 sec and ends at T0+100 sec.  
The T90 duration measured by the SGM data is 95.0 +- 1.4 s (40-920 keV).  

Currently, CALET is in the commissioning phase.  Further information about CALET and 
CGBM can be found at http://calet.jp/en/ and http://www.en.yoshida-agu.net/research/calet-gbm