GCN Circular 32629

M. Dafcikova, J. Ripa (Masaryk U.), A. Pal (Konkoly Observatory), N. 
Werner (Masaryk U.), M. Ohno, H. Takahashi (Hiroshima U.), L. Meszaros, 
B. Csak (Konkoly Observatory), N. Husarikova, J.-P. Breuer, F. Munz , 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 220915A (Fermi-GBM detection trigger 684911625; 
Konus-Wind detection at 2022-09-15 05:13:46.2 UT; INTEGRAL/SPI-ACS 
detection at 2022-09-15 05:13:43 UT) was detected by the GRBAlpha 1U 
CubeSat (Pal et al. Proc. SPIE 2020).

The 8.4 sigma detection was confirmed at the peak time 2022-09-15 
05:13:42.9 UTC. The GRB has the T90 duration of 12 s.

The light curve obtained by GRBAlpha is available here:
https://grbalpha.konkoly.hu/static/share/GRB220915A_GCN.pdf

GRBAlpha is a demonstration mission for a future CubeSats constellation 
(Werner et al. Proc. SPIE 2018). The detector of GRBAlpha consists of a 
75 x 75 x 5 mm3 CsI scintillator read out by a SiPM array, covering the 
energy range from ~50 keV to ~1000 keV. GRBAlpha was launched on 2021 
March 22 from Baikonur. After its commissioning phase, the scientific 
observations are now under way. To increase the duty cycle and the 
downlink rate, the upgrade of the on-board data acquisition software 
stack is in progress. The ground segment is also supported by the radio 
amateur community and it takes advantage of the SatNOGS network for 
increased data downlink volume.