TITLE:   GCN CIRCULAR
NUMBER:  27777
SUBJECT: GRB 200521A: CALET Gamma-Ray Burst Monitor detection
DATE:    20/05/22 09:52:36 GMT
FROM:    Valentin Pal'shin at AGU  <val@phys.aoyama.ac.jp>

A. Yoshida, T. Sakamoto, V. Pal'shin, S. Sugita (AGU),
Y. Kawakubo (LSU), K. Yamaoka (Nagoya U), S. Nakahira (RIKEN),
Y. Asaoka, S. Torii (Waseda U), Y. Shimizu, T. Tamura (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 bright short hard GRB 200521A (AGILE/MCAL and ratemeters detection:
Verrecchia et al., GCN Circ. 27776) triggered the CALET Gamma-ray Burst
Monitor (CGBM) at 12:16:40.803 UTC on 21 May 2020.
The burst signal was seen by all CGBM detectors.
Because of a problem in one of the ground alert processing script, the GCN
notice was not distributed automatically for this event.

The burst light curve shows a bright pulse which starts at T-0.304 sec,
peaks at -0.016 sec and ends at T+0.056 sec. The T90 and T50 durations
measured by the SGM data are 0.240 +- 0.094 sec and 0.104 +- 0.018 sec
(40-1000 keV), respectively.

The ground processed light curve is available at

http://cgbm.calet.jp/cgbm_trigger/ground/1274098167/

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