GRB 221028A: Detection by VZLUSAT-2

A long-duration GRB 221028A (Swift/BAT detection: Lien et al., GCN Circ. 32874; AGILE detection: Ursi et al., GCN Circ. 32885; KONUS-Wind detection: trig. time 2022-10-28 13:16:29.550 UT; INTEGRAL/SPI-ACS detection peak at 2022-10-28 13:16:28.3 UT) was detected by both GRB detector units on board of the VZLUSAT-2 3U CubeSat (https://www.vzlusat2.cz/en/). The data acquisition was performed by GRB detector units no. 0 and no. 1. The 7.1 (6.1) sigma detection significance was confirmed at detector unit no. 0 (no. 1) at 2022-10-28 13:16:26 UTC. The T90 duration was measured to be 23 s (26 s) for detector unit no. 0 (no. 1). The light curve obtained by VZLUSAT-2 is available here: https://vzlusat2.konkoly.hu/static/share/GRB221028A_GCN_VZLUSAT2.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.