TITLE: GCN CIRCULAR NUMBER: 32794 SUBJECT: SGR 1935+2154: Detection by GRBAlpha DATE: 22/10/18 15:13:13 GMT FROM: Marianna Dafcikova at Masaryk University 500025@mail.muni.cz
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), F. Munz, N. Husarikova, J.-P. Breuer, 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 Metropoli tan U.), M. Moritaki (U. Tokyo), T. Kano (U. Michigan) -- the GRBAlpha collaboration.
The recently active SGR 1935+2154 (Fermi-GBM detection: Veres et al., GCN 32764, Konus-Wind detection: Ridnaia et al., GCN 32768) was detected by the GRBAlpha 1U CubeSat (Pal et al. Proc. SPIE 2020). This is the first time an SGR was detected by GRBAlpha.
The 11 sigma detection was confirmed at the peak time 2022-10-14 07:12:27.8 UTC. The temporal resolution of the observation was 4 s and the light curve obtained by GRBAlpha shows an excess in one bin.
The light curve obtained by GRBAlpha is available here: https://grbalpha.konkoly.hu/static/share/SGR1935+2154_GCN.pdf
GRBAlpha, launched on 2021 March 22, is a demonstration mission for a future CubeSat constellation (Werner et al. Proc. SPIE 2018). Its detector consists of a 75 x 75 x 5 mm^3 CsI(Tl) scintillator read out by a SiPM array, covering the energy range from ~50 keV to ~1000 keV. To increase the duty cycle and the downlink rate, we are continuously upgrading the on-board data acquisition software stack. The ground segment is also supported by the radio amateur community, and it takes advantage of the SatNOGS network for increased data downlink volume.