GRB 240905B: VZLUSAT-2 detection

The short-duration GRB 240905B (Fermi/GBM detection: GCN 37389; AstroSat/CZTI detection: GCN 37391; Konus/Wind detection at 2024-09-05 04:27:18.558 UTC; INTEGRAL/SPI-ACS peak detection at 2024-09-05 ~04:27:16 UTC) was detected by the 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 detection was confirmed at the peak time 2024-09-05 04:27:15 UTC. The T90 duration is 1 s and the significance during T90 reaches 11 sigma. The light curve obtained by VZLUSAT-2 is available here: https://vzlusat2.konkoly.hu/static/share/GRB240905B_GCN_VZLUSAT2.pdf All VZLUSAT-2 detections are listed at: https://monoceros.physics.muni.cz/hea/VZLUSAT-2/ 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.