[vsnet-grb-info 20546] GRB 180411A: CALET Gamma-Ray Burst Monitor detection

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  22642
SUBJECT: GRB 180411A: CALET Gamma-Ray Burst Monitor detection
DATE:    18/04/12 12:30:59 GMT
FROM:    Takanori Sakamoto at AGU  <tsakamoto at phys.aoyama.ac.jp>

V. Pal'shin, A. Yoshida, T. Sakamoto, Y. Kawakubo, A. Tezuka, S. Matsukawa,
H. Onozawa (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 long-duration GRB 180411A (Swift-BAT trigger #824451: Liu, et al., GCN Circ. 22630,
Markwardt et al., GCN Circ. 22633; Fermi-GBM detection: Poolakkil, von Kienlin and
Meegan, GCN Circ. 22634) triggered the CALET Gamma-ray Burst Monitor (CGBM) at
12:28:26.665 UTC on 11 April 2018.  The trigger occurred at the exit from the SAA,
44 sec after the BAT trigger.  The burst signal was seen by all CGBM detectors.

The burst light curve shows a multi-peaked structure which starts at T-35 sec, peaks at
T+9 sec and ends at T+36 sec. The T90 and the T50 durations measured by the SGM data are
60.0 +- 6.7 sec and 20.4 +- 9.0 sec (40-1000 keV), respectively.  Since CGBM missed the
initial part of the burst, these values underestimate the real burst durations.

The ground processed light curve is available at

http://cgbm.calet.jp/cgbm_trigger/ground/1207484873/

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