GCN Circular 32196

J. Ripa (Masaryk U.), A. Pal (Konkoly Observatory), M. Ohno (Eotvos 
U./Hiroshima U.),�� N. Werner�� (Masaryk U.),�� L. Meszaros (Konkoly 
Observatory), H. Takahashi (Hiroshima U.), B. Csak (Konkoly 
Observatory), M. Topinka, F. Munz, F. Hroch (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.

A long-duration GRB 220608B (Fermi/GBM trigger 676366592) was detected 
by a GRB detector on board of the VZLUSAT-2 3U CubeSat 
(https://www.vzlusat2.cz/en/).

The data acquisition was performed by the GRB detector unit no. 1. The 
5.9 sigma detection was confirmed at 2022-06-08 07:36:39 UTC. The GRB 
has the T90 duration of 27 s.

The light curve obtained by VZLUSAT-2 is available here:
https://vzlusat2.konkoly.hu/static/share/GRB220608B_GCN_VZLUSAT2.pdf

The light curve obtained by VZLUSAT-2 with the shape and timing matches 
well the light curve obtained by Fermi/GBM. The GOES X-ray flux does not 
show any excess. Therefore our observation is consistent with this event 
being a GRB.

GRB detectors on VZLUSAT-2 are a demonstration payload for a future 
CubeSats 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.