TITLE:   GCN CIRCULAR
NUMBER:  27773
SUBJECT: GRB 200519A: CALET Gamma-Ray Burst Monitor detection
DATE:    20/05/21 14:03:23 GMT
FROM:    Valentin Pal'shin at AGU  <val@phys.aoyama.ac.jp>

P. S. Marrocchesi (U of Siena),
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),
and the CALET collaboration:

The Swift GRB 200519A (Swift detection: Sbarufatti et al.,
GCN Circ. 27756, Stamatikos et al., GCN Circ. 27771;
AstroSat CZTI detection: Gupta et al., GCN Circ. 27766;
Insight-HXMT/HE detection: GCN Circ. 27770;
https://gcn.gsfc.nasa.gov/other/200519A.gcn3) triggered the CALET
Gamma-ray Burst Monitor (CGBM) at 11:20:43.755 UTC on 19 May 2020 (trigger
#1273922014: http://cgbm.calet.jp/cgbm_trigger/flight/1273922014/).
The burst signal was seen mainly by the SGM detector. The source location
was outside the FOV of the HXM detectors.

The burst light curve shows a double-peaked pulse which starts at T-2.0 sec,
peaks at T+4.4 sec and ends at T+5.9 sec. The T90 and T50 durations
measured by the SGM data are 6.9 +- 1.5 sec and 3.3 +- 1.9 sec (40-1000
keV), respectively.

The ground processed light curve is available at

http://cgbm.calet.jp/cgbm_trigger/ground/1273922014/

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