GRB 230304B
GCN Circular 33509
Subject
Konus-Wind detection of GRB 230304B
Date
2023-03-23T13:08:58Z (3 years ago)
From
Dmitry Svinkin at Ioffe Institute <svinkin@mail.ioffe.ru>
D. Svinkin, D. Frederiks, M. Ulanov, A. Tsvetkova,
A. Lysenko, A. Ridnaia, and T. Cline
on behalf of the Konus-Wind team, report:
The long-duration GRB 230304B
(Fermi-GBM detection: the Fermi GBM team, GCN Circ. 33396;
GRBAlpha detection: Dafcikova et al., GCN Circ. 33398;
AstroSat-CZTI detection: Navaneeth et al., GCN Circ. 33400;
CALET-GBM detection: Kobayashi et al., GCN Circ. 33423;
IPN triangulation: Kozyrev et al., GCN Circ. 33480)
triggered Konus-Wind at T0=52553.382 s UT (14:35:53.382).
The burst light curve shows a multi-peaked structure
which starts at ~T0 and has a total duration of ~53 s.
The emission is seen up to ~6 MeV.
The Konus-Wind light curve of this GRB is available at
http://www.ioffe.ru/LEA/GRBs/GRB230304_T52553/
As observed by Konus-Wind, the burst
had a fluence of 4.57(-0.41,+0.60)x10^-5 erg/cm2,
and a 64-ms peak flux, measured from T0+0.560 s,
of 1.21(-0.18,+0.18)x10^-5 erg/cm2/s
(both in the 20 keV - 10 MeV energy range).
The time-averaged spectrum of the burst
(measured from T0 to T0+40.448 s)
is best fit in the 20 keV - 10 MeV range
by the GRB (Band) model with the following parameters:
the low-energy photon index alpha = -1.05(-0.09,+0.09),
the high energy photon index beta = -3.34(-6.66,+0.68),
the peak energy Ep = 299(-28,+32) keV
(chi2 = 68/82 dof).
The spectrum near the maximum count rate
(measured from T0 to T0+7.680 s)
is best fit in the 20 keV - 10 MeV range
by a power law with exponential cutoff model:
dN/dE ~ (E^alpha)*exp(-E*(2+alpha)/Ep)
with alpha = -0.89(-0.08,+0.09)
and Ep = 352(-27,+31) keV (chi2 = 91/83 dof).
Fitting by a GRB (Band) model yields the same alpha and Ep,
and an upper limit on the high energy photon index: beta < -3.2
(chi2 = 91/82 dof).
All the quoted errors are at the 90% confidence level.
All the quoted values are preliminary.
GCN Circular 33480
Subject
IPN triangulation of GRB 230304B
Date
2023-03-15T14:52:07Z (3 years ago)
From
Dmitry Svinkin at Ioffe Institute <svinkin@mail.ioffe.ru>
A.S. Kozyrev, D.V. Golovin, M.L. Litvak, I.G. Mitrofanov, and A.B. Sanin
on behalf of the MGNS/BepiColombo and HEND/Mars Odyssey teams,
J. Benkhoff on behalf of the BepiColombo team,
D. Svinkin, D. Frederiks, A. Ridnaia, A. Lysenko,
and T. Cline on behalf of the Konus-Wind team,
A. Goldstein, M. S. Briggs, C. Wilson-Hodge,
and E. Burns on behalf of the Fermi GBM team,
E. Bozzo and C. Ferrigno, on behalf of the INTEGRAL SPI-ACS GRB team,
and
W. Boynton, C. Fellows, K. Harshman, H. Enos, R. Starr,
and A.S. Gardner on on behalf of the GRS-Odyssey GRB team,
report:
The long-duration GRB 230304B
(Fermi-GBM detection: the Fermi GBM team, GCN Circ. 33396;
GRBAlpha detection: Dafcikova et al., GCN Circ. 33398;
AstroSat-CZTI detection: Navaneeth et al., GCN Circ. 33400;
CALET-GBM detection: Kobayashi et al., GCN Circ. 33423)
was detected by Fermi (GBM trigger 699633354),
Konus-Wind, INTEGRAL (SPI-ACS), GRBAlpha, AstroSat (CZTI),
CALET (GBM), BepiColombo (MGNS), and Mars-Odyssey (HEND),
at about 52549 s UT (14:35:49).
We have triangulated it to a preliminary, 3 sigma error box
whose coordinates are:
---------------------------------------------
RA(2000), deg Dec(2000), deg
---------------------------------------------
Center:
110.440 (07h 21m 46s) -2.113 ( -2d 06' 48")
Corners:
110.528 (07h 22m 07s) -2.101 ( -2d 06' 03")
110.345 (07h 21m 23s) -2.288 ( -2d 17' 16")
110.352 (07h 21m 24s) -2.126 ( -2d 07' 33")
110.535 (07h 22m 08s) -1.938 ( -1d 56' 16")
---------------------------------------------
The error box area is 103 sq. arcmin, and its maximum
dimension is 24 arcmin (the minimum one is 6.5 arcmin).
The Sun distance was 124 deg.
This box may be improved.
The IPN localization is consistent with, but reduces the area of,
the Fermi-GBM final localization (GCN 33396).
A triangulation map and HEALPix FITS file are posted at
http://www.ioffe.ru/LEA/GRBs/GRB230304_T52553/IPN/
The Konus-Wind time history and spectrum will be given in a forthcoming
GCN Circular.
GCN Circular 33423
Subject
GRB 230304B: CALET Gamma-Ray Burst Monitor detection
Date
2023-03-08T16:07:13Z (3 years ago)
From
Yuta Kawakubo at Louisiana State U./CALET <kawakubo1@lsu.edu>
K. Kobayashi (Waseda U), A. Yoshida, T. Sakamoto, S. Sugita (AGU),
Y. Kawakubo (LSU), K. Yamaoka (Nagoya U), S. Nakahira (RIKEN),
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 long GRB 230304B (Fermi GBM Final Real-time Localization: Fermi GBM team,
GCN Circ. 33396; AstroSat CZTI detection: Navaneeth et al., GCN Circ 33400)
triggered the CALET Gamma-ray Burst Monitor (CGBM) at 14:35:45.442 UTC
on 4 March 2023
(http://cgbm.calet.jp/cgbm_trigger/flight/1361975601/index.html).
The burst signal was seen by only the SGM detector.
The burst light curve shows a multi-peaked structure that starts
at T+3.6 sec, peaks at T+4.1 sec, and ends at T+19.3 sec.
The T90 and T50 durations measured by the SGM data are 14.4 +/- 0.3 sec
and 9.5 +/- 0.3 sec (40-1000 keV), respectively.
The ground-processed light curve is available at
http://cgbm.calet.jp/cgbm_trigger/ground/1361975601/
The CALET data used in this analysis are provided by
the Waseda CALET Operation Center located at Waseda University.
GCN Circular 33400
Subject
GRB 230304B: AstroSat CZTI detection
Date
2023-03-06T06:39:48Z (3 years ago)
From
Gaurav Waratkar at IIT,Bombay <gauravwaratkar@iitb.ac.in>
P K. Navaneeth (IUCAA), R. Gopalakrishnan (IUCAA), G. Waratkar (IITB),
A. Vibhute (IUCAA), V. Bhalerao (IITB), D. Bhattacharya (Ashoka
University/IUCAA), A. R. Rao (IUCAA/TIFR), and S. Vadawale (PRL) report
on behalf of the AstroSat CZTI collaboration:
Analysis of AstroSat CZTI data with the CIFT framework (Sharma et al.,
2021, JApA, 42, 73) showed the detection of a GRB 230304B which was also
detected by Fermi GBM (GCN Circ. 33396) and GRBAlpha (Dafcikova et al.,
GCN Circ. 33398).
The source was clearly detected in the 20-200 keV energy range. The
light curve showed multiple peaks of emission with the strongest peak at
2023-03-04 14:35:49.5 UTC. The measured peak count rate associated with
the burst is 640 (+51, -54) counts/s above the background in the
combined data of three quadrants (out of four), with a total of 4194
(+351, -404) counts. The local mean background count rate was 319 (+3,
-5) counts/s. Using cumulative rates, we measure a T90 of 22.11 (+3, -4)
s.
It was also clearly detected in the CsI anticoincidence (Veto) detector
in the 100-500 keV energy range. The light curve peaks at 2023-03-04
14:35:48.9 UTC. The measured peak count rate is 1900 (+90, -100)
counts/s above the background in the combined Veto data of all
quadrants, with a total of 12984 (+592, -623) counts. The local mean
background count rate was 1314 (+7, -6) counts/s. We measure a T90 of
20.5 (+2, -2) s from the cumulative Veto light curve.
CZTI GRB detections are reported regularly on the payload site at
http://astrosat.iucaa.in/czti/?q=grb. CZTI is built by a TIFR-led
consortium of institutes across India, including VSSC, URSC, IUCAA, SAC,
and PRL. The Indian Space Research Organisation funded, managed, and
facilitated the project.
GCN Circular 33398
Subject
GRB 230304B: Detection by GRBAlpha
Date
2023-03-05T23:21:27Z (3 years ago)
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), N. Husarikova, F. Munz , M. Topinka, 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 230304B (Fermi/GBM detection: GCN Circ. 33396;
CALET/CGBM detection: trigger no. 1361975601; INTEGRAL/SPI-ACS detection at
2023-03-04 14:35:47.510) was observed by the GRBAlpha 1U CubeSat (Pal et
al. Proc. SPIE 2020).
The detection was confirmed at the peak time 2023-03-04 14:35:49 UTC. The
T90 duration measured by GRBAlpha is 16 s and the overall significance
during T90 reaches 28 sigma.
The light curve obtained by GRBAlpha is available here:
https://grbalpha.konkoly.hu/static/share/GRB230304B_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 33396
Subject
GRB 230304B: Fermi GBM Final Real-time Localization
Date
2023-03-04T14:46:09Z (3 years ago)
From
Fermi GBM Team at MSFC/Fermi-GBM <do_not_reply@GIOC.nsstc.nasa.gov>
The Fermi GBM team reports the detection of a likely LONG GRB
At 14:35:49 UT on 4 Mar 2023, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 230304B (trigger 699633354.142652 / 230304608).
The on-ground calculated location, using the Fermi GBM trigger data, is RA = 111.7, Dec = 0.9 (J2000 degrees, equivalent to J2000 07h 26m, 0d 54'), with a statistical uncertainty of 1.0 degrees.
The angle from the Fermi LAT boresight is 28.0 degrees.
The skymap can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2023/bn230304608/quicklook/glg_skymap_all_bn230304608.png
The HEALPix FITS file, including the estimated localization systematic, can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2023/bn230304608/quicklook/glg_healpix_all_bn230304608.fit
The GBM light curve can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2023/bn230304608/quicklook/glg_lc_medres34_bn230304608.gif