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GCN Circular 33273

GRB 230204B: Detection by GRBAlpha
2023-02-05T16:58:49Z (a year ago)
Marianna Dafcikova at Masaryk University <>
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, F. Munz , M. Topinka, M. Kolar, J.-P.
Breuer, 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 230204B (MAXI/GSC detection: GCN Circ. 33265;
Swift/BAT-GUANO detection: GCN Circ. 33267; AstroSat detection: GCN Circ.
33268; AGILE/MCAL detection: GCN Circ. 33272; Fermi/GBM detection: trigger
no. 697239872; CALET/GCBM detection: trigger no. 1359582171; INTEGRAL/SPI-ACS
detection: trigger no. 10188) was observed by the GRBAlpha 1U CubeSat (Pal
et al. Proc. SPIE 2020).

The detection was confirmed at the peak time 2023-02-04 21:47:03 UTC. The
T90 duration measured by GRBAlpha is 207 s and the maximum significance
during T90 reaches 25 sigma in the 110-370 keV band.

The light curve obtained by GRBAlpha is available here:

All GRBAlpha detections are listed at:

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.
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