TITLE:   GCN CIRCULAR
NUMBER:  25865
SUBJECT: GRB 190928A: CALET Gamma-Ray Burst Monitor detection
DATE:    19/09/30 08:17:04 GMT
FROM:    Valentin Pal'shin at AGU  <val@phys.aoyama.ac.jp>

V. Pal'shin, A. Yoshida, T. Sakamoto, 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 long bright GRB 190928A (AGILE/MCAL detection: Ursi et al., GCN Circ.
25859; IPN triangulation: Hurley et al., GCN Circ. 25864) triggered the
CALET Gamma-ray Burst Monitor (CGBM) at 13:12:11.187 UTC on 28 September
2019. The burst signal was seen by all CGBM detectors.

The burst light curve shows two multi-peaked pulses separated by a period
of low-level emission. The first pulse starts at T+2.6 sec, peaks at
T+4.8 sec and ends at T+8.1 sec, the second, much brighter, pulse starts at
T+76.4 sec, peaks at T+106.1 sec and ends at T+175.5 sec.
The T90 and T50 durations measured by the SGM data are 106.6 +- 49.1 sec and
6.9 +- 0.4 sec (40-1000 keV), respectively.

The ground processed light curve is available at

http://cgbm.calet.jp/cgbm_trigger/ground/1253711524/

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