TITLE:   GCN CIRCULAR
NUMBER:  32953
SUBJECT: GRB 221119A: Detection by GRBAlpha
DATE:    22/11/20 15:07:20 GMT
FROM:    Andras Pal at Konkoly Observatory  <apal@konkoly.hu>

A. Pal (Konkoly Observatory), J. Ripa, M. Dafcikova, N. Werner (Masaryk 
U.), M. Ohno, H. Takahashi (Hiroshima U.), L. Meszaros, B. Csak (Konkoly 
Observatory), F. Munz, N. Husarikova, J.-P. Breuer, M. Topinka, F. Hroch 
(Masaryk U.), T. Urbanec, M. Kasal, A. Povalac (Brno U. of Technology), J. 
Hudec, J. Kapus, M. Frajt (Spacemanic s.r.o), R. Laszlo, M. Koleda 
(Needronix s.r.o), M. Smelko, P. Hanak, P. Lipovsky (Technical U. of 
Kosice), G. Galgoczi (Wigner Research Center/Eotvos U.), Y. Uchida, H. 
Poon, H. Matake (Hiroshima U.), N. Uchida (ISAS/JAXA), T. Bozoki (Eotvos 
U.), G. Dalya (Eotvos U.), T. Enoto (Kyoto U.), Zs. Frei (Eotvos U.), G. 
Friss (Eotvos U.), Y. Fukazawa, K. Hirose (Hiroshima U.), S. Hisadomi 
(Nagoya U.), Y. Ichinohe (Rikkyo U.), K. Kapas (Eotvos U.), L. L. Kiss 
(Konkoly Observatory), T. Mizuno (Hiroshima U.), K. Nakazawa (Nagoya U.), 
H. Odaka (Univ of Tokyo), J. Takatsy (Eotvos U.), K. Torigoe (Hiroshima 
U.), N. Kogiso, M. Yoneyama (Osaka Metropolitan U.), M. Moritaki (U. 
Tokyo), T. Kano (U. Michigan) -- the GRBAlpha collaboration.

The long-duration GRB 221119A (Fermi/GBM detection: GCN Circ. 32950; 
GECAM-B detection at 2022-11-19 15:02:54.65 UT, trigg. num. 72; also 
detected by INTEGRAL/SPI-ACS) was detected by the GRBAlpha 1U CubeSat (Pal 
et al. Proc. SPIE 2020). The first double-peaked signal, acquired with a 
1-second cadence was confirmed with a ~14 sigma detection at the peak 
times of 2022-11-19 15:02:55 and 15:02:58 UTC, respectively. In addition, 
the presence, duration and amplitude of the second peak is also confirmed 
by the GRBAlpha light curve 40-50 seconds after the double peaks. The T90 
duration of this GRB is 54 seconds and the overall significance during T90 
reaches 23.5.

The light curve obtained by GRBAlpha is available here: 
https://grbalpha.konkoly.hu/static/share/GRB221119A_GCN.pdf

GRBAlpha, launched on 2021 March 22, is a demonstration mission for a 
future CubeSat constellation (Werner et al. Proc. SPIE 2018). Its detector 
consists of a 75 x 75 x 5 mm^3 CsI(Tl) scintillator read out by a SiPM 
array, covering the energy range from ~50 keV to ~1000 keV. To increase 
the duty cycle and the downlink rate, we are continuously upgrading the 
on-board data acquisition software stack. The ground segment is also 
supported by the radio amateur community, and it takes advantage of the 
SatNOGS network for increased data downlink volume, also allowing us the 
retrieval with a small latency. We would like to thank the support of the 
operators of the individual receiver stations as well as the maintenance 
of the network itself.