TITLE:   GCN CIRCULAR
NUMBER:  31226
SUBJECT: GRB 211211A: CALET Gamma-Ray Burst Monitor detection
DATE:    21/12/13 08:58:30 GMT
FROM:    Valentin Pal'shin at AGU  <val@phys.aoyama.ac.jp>

T. Tamura (Kanagawa U),
A. Yoshida, T. Sakamoto, V. Pal'shin, S. Sugita (AGU),
Y. Kawakubo (LSU), K. Yamaoka (Nagoya U), S. Nakahira (RIKEN),
Y. Asaoka (ICRR), S. Torii, Y. Akaike, K. Kobayashi (Waseda U),
Y. Shimizu (Kanagawa U), N. Cannady (GSFC/UMBC), M. L. Cherry (LSU),
S. Ricciarini (U of Florence), P. S. Marrocchesi (U of Siena),
and the CALET collaboration:

The long bright GRB 211211A (Swift detection: Ambrosi et al.,
GCN Circ. 31202, Stamatikos et al., GCN Circ. 31209;
Fermi GBM observation: Mangan et al., GCN Circ. 31210;
https://gcn.gsfc.nasa.gov/other/211211A.gcn3)
triggered the CALET Gamma-ray Burst Monitor (CGBM) at 13:09:57.513 UTC
on 11 December 2021
(http://cgbm.calet.jp/cgbm_trigger/flight/1323263412/index.html).
The burst signal was seen by all CGBM detectors.

The burst light curve shows several partially overlapped multi-peaked
pulses which start at T+3.6 sec, peak at T+9.1 sec,and end at T+73.1 sec.
The T90 and T50 durations measured by the SGM data are 33.8 +- 0.9 sec and
12.1 +- 0.4 sec (40-1000 keV), respectively.

The ground processed light curve is available at

http://cgbm.calet.jp/cgbm_trigger/ground/1323263412/

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