GRB 220421B
GCN Circular 31937
Subject
GRB 220421B: Detection by VZLUSAT-2
Date
2022-04-23T15:55:15Z (3 years ago)
From
Jakub Ripa at Masaryk University <ripa.jakub@mail.muni.cz>
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 GRB detected by GECAM (trigger at 2022-04-21 21:03:20.6 observation ID
00035461090, https://www.swift.psu.edu/guano/) was also detected by both
GRB detector units on board of the VZLUSAT-2 3U CubeSat
(https://www.vzlusat2.cz/en/). Note that the reported GECAM trigger is
~15s earlier than the onset of the GRB seen by VZLUSAT-2.
The data acquisition was performed by GRB detector units no. 0 and no.
1. The 38 sigma detection significance was confirmed at 2022-04-21
21:03:47 UTC. The long-duration GRB has the T90 duration of 62 s.
The light curve obtained by VZLUSAT-2 is available here:
https://vzlusat2.konkoly.hu/static/share/GRB220421B_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.
GCN Circular 31949
Subject
Correction to 31937: GRB 220421B: Detection by VZLUSAT-2
Date
2022-04-25T16:52:18Z (3 years ago)
From
Jakub Ripa at Masaryk University <ripa.jakub@mail.muni.cz>
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.
In Ripa et al. GCN 31937 we reported a detection of the GRB 220421B.
Based on the GOES-16 and GOES-17 X-ray data the reported burst is
probably not a GRB but a solar flare. The GOES X-ray light curves show a
peak at 2022-04-21 21:04:00 UT which coincides with the peak in the rate
curves from the GRB detectors on board the VZLUSAT-2 nanosatellite. The
Sun was in the field of view of the VZLUSAT-2/GRB detectors.
We apologize for any inconvenience.