GRB 250313A
GCN Circular 39786
Subject
GRB 250313A: GRBAlpha detection
Date
2025-03-19T21:08:05Z (a year ago)
From
Michaela Ďuríšková at Masaryk University <505876@mail.muni.cz>
Via
Web form
M. Duriskova, 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), N. Husarikova, F. Munz , M. Topinka, L. Szakszonova, M. Kolar,J.-P. Breuer, 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 Metropolitan U.), M. Moritaki (U. Tokyo), T. Kano (U. Michigan) -- the GRBAlpha collaboration.
The long-duration GRB 250313A (FERMI/GBM: GCN Circular 39703, FERMI/LAT: GCN Circular 39711, AstroSat/CZTI: GCN Circular 39714, SVOM/GRM: GCN Circular 39716, Konus-Wind: GCN Circular 39721, CALET/CGBM: GCN Circular 39725) was observed by the GRBAlpha 1U CubeSat (Pal et al. 2023, A&A, 677, 40; https://ui.adsabs.harvard.edu/abs/2023A%26A...677A..40P/abstract).
The detection was confirmed at the peak time 2025-03-13 14:34:41.7 UTC. The T90 duration measured by GRBAlpha is 13 s and the overall significance during T90 reaches 52.3 sigma.
The light curve obtained by GRBAlpha is available here: https://grbalpha.konkoly.hu/static/share/GRB250313A_GCN.pdf
All GRBAlpha detections are listed at: https://monoceros.physics.muni.cz/hea/GRBAlpha/
GRBAlpha, launched on 2021 March 22, is a demonstration mission for a future CubeSat constellation (Werner et al. Proc. SPIE 2018). The detector of GRBAlpha consists of a 75 x 75 x 5 mm3 CsI 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, the upgrade of the on-board data acquisition software stack is in progress. The ground segment is also supported by the radio amateur community and it takes advantage of the SatNOGS network for increased data downlink volume.
GCN Circular 39726
Subject
GRB 250313A: Fermi GBM Detection
Date
2025-03-15T02:17:47Z (2 years ago)
From
eliza.neights@gmail.com
Via
Web form
Eliza Neights (George Washington University, NASA Goddard Space Flight Center), M. Godwin (UAH), C. Meegan (UAH) and O.J. Roberts (USRA) report on behalf of
the Fermi Gamma-ray Burst Monitor Team:
"At 14:34:33.69 UT on 13 March 2025, the Fermi Gamma-ray Burst Monitor (GBM)
triggered and located GRB 250313A (trigger 763569278/250313607), which was also detected by Fermi LAT (Di Lalla et al. 2025, GCN 39711), AstroSat CZTI (Dasgupta et al. 2025, GCN 39714),
SVOM/GRM (Wang et al. 2025, GCN 39716), and Konus-Wind (Frederiks et al. 2025, GCN 39721).
The Fermi GBM Final Position location is consistent with the Fermi LAT position.
The angle from the Fermi LAT boresight is 4 degrees.
The GBM light curve consists of two emission episodes, a bright pulse lasting 12 s after the trigger time and a dimmer pulse about 280 s later. The duration (T90)
is about 295.2 s (50-300 keV). The time-averaged spectrum
from T0-2.2 to T0+389.0 s is best fit by
a power law function with an exponential high-energy cutoff.
The power law index is -1.36 +/- 0.01 and the cutoff energy,
parameterized as Epeak, is 320 +/- 20 keV.
The event fluence (10-1000 keV) in this time interval is
(9.4 +/- 0.1)E-05 erg/cm^2. The 1-sec peak photon flux measured
starting from T0+4.7 s in the 10-1000 keV band is 55.4 +/- 0.5 ph/s/cm^2.
The spectrum is fit about equally well by a Band function with Epeak = 280 +/- 20 keV, alpha = -1.34 +/- 0.02, and beta = -2.23 +/- 0.13.
The spectral analysis results presented above are preliminary;
final results will be published in the GBM GRB Catalog:
https://heasarc.gsfc.nasa.gov/W3Browse/fermi/fermigbrst.html
For Fermi GBM data and info, please visit the official Fermi GBM Support Page:
https://fermi.gsfc.nasa.gov/ssc/data/access/gbm/"
GCN Circular 39725
Subject
GRB 250313A: CALET Gamma-Ray Burst Monitor detection
Date
2025-03-15T01:55:09Z (2 years ago)
From
Yuta Kawakubo at Aoyama Gakuin University <kawakubo@phys.aoyama.ac.jp>
Via
Web form
K. Yamaoka (Nagoya U), A. Yoshida, T. Sakamoto, S. Sugita,
Y. Kawakubo (AGU), S. Nakahira (JAXA), Y. Asaoka (ICRR), S. Torii,
Y. Akaike, K. Kobayashi (Waseda U), Y. Shimizu, T. Tamura (Kanagawa U),
N. Cannady (GSFC/UMBC), M. L. Cherry (LSU), S. Ricciarini (U of Florence),
P. S. Marrocchesi (U of Siena),
and the CALET collaboration:
The CALET Gamma-ray Burst Monitor (CGBM) was triggered by GRB 250313A
at 14:34:30.53 UTC on 13 March 2025, which is also detected by Fermi-GBM
(Fermi-GBM team, GCN #39703), Fermi-LAT (Di Lalla et al., GCN #39711),
AstroSat CZTI (Dasgupta et al., GCN #39714), SVOM/GRM (Wang et al, GCN #39716