TITLE: GCN CIRCULAR NUMBER: 32797 SUBJECT: SGR 1935+2154: Bursting activity detected by VZLUSAT-2 DATE: 22/10/18 22:39:15 GMT FROM: Jakub Ripa at Masaryk University 245487@mail.muni.cz

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. Dafcikova, N. Husarikova, M. Topinka, F. Hroch, 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 recently active SGR 1935+2154 (Fermi-GBM detection: Malacaria et al., GCN Circ. 32737, Konus-Wind detection: Ridnaia et al., GCN Circ. 32768) was detected by the GRB detector module no. 1 on board of the VZLUSAT-2 3U CubeSat (https://www.vzlusat2.cz/en/).

The list of detected SGR bursts with their significance is:

Date and time in UTC     SNR 2022-10-12 23:26:41      17.6 2022-10-13 02:02:43      16.5 2022-10-13 22:41:28      125

The light curves obtained by VZLUSAT-2 are available here: https://vzlusat2.konkoly.hu/static/share/SGR_1935_2154_GCN_VZLUSAT-2.pdf

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.