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GCN Circular 33590

GRB 230405B: VZLUSAT-2 detection
2023-04-07T21:07:07Z (a year ago)
Marianna Dafcikova at Masaryk University <>
M. Dafcikova, J. Ripa (Masaryk U.), A. Pal (Konkoly Observatory),  N.
Werner  (Masaryk U.), M. Ohno (Hiroshima U.),  L. Meszaros, B. Csak
(Konkoly Observatory), H. Takahashi (Hiroshima U.), F. Munz , M. Topinka,
F. Hroch, N. Husarikova, J.-P. Breuer (Masaryk U.), J. Hudec, J. Kapus, M.
Frajt, M. Rezenov (Spacemanic s.r.o), R. Laszlo (Needronix), G. Galgoczi
(Wigner Research Center/Eotvos U.), N. Uchida (ISAS/JAXA), T. Enoto (Kyoto
U.), Zs. Frei (Eotvos U.), Y. Fukazawa, K. Hirose, H. Matake (Hiroshima
U.), S. Hisadomi (Nagoya U.), Y. Ichinohe (Rikkyo U.), L. L. Kiss (Konkoly
Observatory),  T. Mizuno (Hiroshima U.), K. Nakazawa (Nagoya U.), H. Odaka
(Univ of Tokyo), K. Torigoe (Hiroshima U.), P. Svoboda, V. Daniel, J.
Dudas, M. Junas, J. Gromes (VZLU), I. Vertat (FEL ZCU)  -- the
VZLUSAT-2/GRB payload collaboration.

The long duration GRB 230405B (Fermi/GBM detection: GCN 33570; Swift/BAT
detection: GCN 33571; AstroSat detection: GCN 33575; AGILE detection: GCN
33585; Konus/Wind detection: GCN 33586; INTEGRAL/SPI-ACS detection at
2023-04-05 19:58:04) was detected by the GRB detector on board of the
VZLUSAT-2 3U CubeSat (

The data acquisition was performed by the GRB detector unit no. 1 and the
detection was confirmed at the peak time 2023-04-05 19:58:04 UTC. The T90
duration was measured to be 3 s with the light curve resolution of 1 s. The
significance during T90 reaches 25 sigma.

The light curve obtained by VZLUSAT-2 is available here:

All VZLUSAT-2 detections are listed at:

The GRB detectors on VZLUSAT-2 are a demonstration payload for a future
CubeSat constellation (Werner et al. Proc. SPIE 2018). Two GRB modules of
VZLUSAT-2 are placed in a perpendicular manner and each consists of a 75 x
75 x 5 mm3 CsI scintillator read out by a SiPM array, covering the energy
range from ~30 keV to ~1000 keV. VZLUSAT-2 was launched on 2022 January 13
from Cape Canaveral.
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