GRB 230320B
GCN Circular 33515
Subject
GRB 230320B: Fermi GBM Observation
Date
2023-03-24T21:32:11Z (3 years ago)
From
Sarah Dalessi at UAH <sd0104@uah.edu>
S. Dalessi (UAH), C. Fletcher (USRA) and C. Meegan (UAH) report on behalf of
the Fermi Gamma-ray Burst Monitor Team:
"At 21:12:25 UT on 20 March 2023, the Fermi Gamma-ray Burst Monitor (GBM)
triggered and located GRB 230320B (trigger 701039550/230320884).
which was also detected by AstroSat (P K. Navaneeth et al. 2023, GCN
33492), Swift/BAT-GUANO (S. Ronchini et al. 2023, GCN 33499) CALET (T.
Tamura et al. 2023, GCN 33501), and GRBAlpha (M. Dafcikova et al.
2023, GCN 33503).
The on-ground calculated location, using the GBM trigger
data, is RA = 28.11, DEC = 68.88 (J2000 degrees,
equivalent to 01 h 52 m, 68 d 53��� ), with a statistical uncertainty
of 2.6 degrees (radius, 1-sigma containment,
statistical only; there is additionally a systematic
error which we have characterized as a core-plus-tail model, with 90% of
GRBs having a 3.7 deg error and a small tail suffering a larger than 10 deg
systematic error. [Connaughton et al. 2015, ApJS, 216, 32] ).
The angle from the Fermi LAT boresight is 140 degrees.
The GBM light curve consists of a single emission episode with a duration (T90)
of about 15 s (50-300 keV). The time-averaged spectrum
from T0+0.003 to T0+15.616 s is best fit by a power law function with
an exponential
high-energy cutoff.The power law index is -0.30 +/- 0.09 and
the cutoff energy, parameterized as Epeak = 186 +/- 8 keV.
The event fluence (10-1000 keV) in this time interval is
(1.02 +/- 0.03)E-05 erg/cm^2. The 1-sec peak photon flux measured
starting from T0 s in the 10-1000 keV band is 12.7 +/- 0.6 ph/s/cm^2.
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 33503
Subject
GRB 230320B: GRBAlpha detection
Date
2023-03-22T16:38:18Z (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 230320B (AstroSat/CZTI detection: GCN 33492;
Swift/BAT-GUANO detection: GCN 33499; CALET/CGBM detection: GCN 33501;
Fermi/GBM detection: trigger no. 701039550; GECAM-B detection: trigger no.
163; Konus/Wind detection at 2023-03-20 21:12:25.277 UT) was observed by
the GRBAlpha 1U CubeSat (Pal et al. Proc. SPIE 2020).
The detection was confirmed at the peak time 2023-03-20 21:12:27 UTC. The
T90 duration measured by GRBAlpha is 26 s and the overall significance
during T90 reaches 22.5 sigma.
The light curve obtained by GRBAlpha is available here:
https://grbalpha.konkoly.hu/static/share/GRB230320B_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 33501
Subject
GRB 230320B: CALET Gamma-Ray Burst Monitor detection
Date
2023-03-22T04:03:08Z (3 years ago)
From
Yuta Kawakubo at Louisiana State U./CALET <kawakubo1@lsu.edu>
T. Tamura (Kanagawa 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 (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 230320B (AstroSat CZTI detection: Navaneeth
et al., GCN Circ 33492) triggered the CALET Gamma-ray Burst
Monitor (CGBM) at 21:12:22.70 UTC on 20 March 2023
(http://cgbm.calet.jp/cgbm_trigger/flight/1363381768/index.html).
The burst signal was seen by only the SGM detector.
The burst light curve shows a single pulse that starts
at T+2.4 sec, peaks at T+3.5 sec, and ends at T+20.3 sec.
The T90 and T50 durations measured by the SGM data are 16.5 +/- 4.0 sec
and 5.0 +/- 1.0 sec (40-1000 keV), respectively.
The ground-processed light curve is available at
http://cgbm.calet.jp/cgbm_trigger/ground/1363381768/
The CALET data used in this analysis are provided by
the Waseda CALET Operation Center located at Waseda University.
GCN Circular 33499
Subject
GRB 230320B: Swift/BAT-GUANO detection outside the coded FOV
Date
2023-03-21T23:43:53Z (3 years ago)
From
Aaron Tohuvavohu at U Toronto <aaron.tohu@gmail.com>
Samuele Ronchini (PSU), Gayathri Raman (PSU), Jamie A. Kennea (PSU),
James DeLaunay (UAlabama), Aaron Tohuvavohu (U Toronto) report:
Swift/BAT did not localize GRB 230320B onboard (T0:
2023-03-20T21:12:25 UTC, Fermi/GBM trig 701039550, CALET trig
1363381768, GECAM trig 163, AstroSat/CZTI GCN 33492).
The Fermi, CALET and GECAM notices, distributed in near real-time,
triggered the Swift Mission Operations Center operated Gamma-ray
Urgent Archiver for Novel Opportunities (GUANO; Tohuvavohu et al.
2020, ApJ, 900, 1).
Upon trigger by this notice, GUANO sent a command to the Swift Burst
Alert Telescope (BAT) to save 200 seconds of BAT event-mode data from
[-50,+150] seconds around the time of the burst. All the requested
event mode data was delivered to the ground.
The BAT likelihood search, NITRATES (DeLaunay + Tohuvavohu 2022, ApJ,
941, 169), detects the burst with a sqrt(TS) of 12.04 in a 4.096 s
analysis time bin.
The Fermi/GBM localization is consistent with being outside the BAT FOV.
See Section 9.1 and Figures 10 and 17 in the NITRATES paper for brief
descriptions and interpretation of sqrt(TS), DeltaLLHPeak, and
DeltaLLHOut.
GUANO is a fully autonomous, extremely low latency, spacecraft
commanding pipeline designed for targeted recovery of BAT event mode
data around the times of compelling astrophysical events to enable
more sensitive GRB searches.
A live reporting of Swift/BAT event data recovered by GUANO can be
found at: https://www.swift.psu.edu/guano/
GCN Circular 33492
Subject
GRB 230320B: AstroSat CZTI detection
Date
2023-03-21T09:11:08Z (3 years ago)
From
Gaurav Waratkar at IIT,Bombay <gauravwaratkar@iitb.ac.in>
P K. Navaneeth (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 long GRB 230320B which was
also detected by Fermi GBM (TrigNum: 701039550), CALET (ID Num:
1363381768) and GECAM (TrigNum: 163).
The source was clearly detected in the 20-200 keV energy range. The
light curve peaks at 2023-03-20 21:12:27.50 UTC. The measured peak count
rate associated with the burst is 415 (+48, -33) counts/s above the
background in the combined data of three quadrants (out of four), with a
total of 1976 (+332, -251) counts. The local mean background count rate
was 360 (+2, -3) counts/s. Using cumulative rates, we measure a T90 of
11.27 (+6, -4) s.
The source was also clearly detected in the CsI anticoincidence (Veto)
detector in the 100-500 keV energy range. The light curve peaks at
2023-03-20 21:12:26.59 UTC. The measured peak count rate associated with
the burst is 377 (+80, -44) counts/s above the background in the
combined data of all quadrants, with a total of 1527 (+371, -423)
counts. The local mean background count rate was 1564 (+4, -4) counts/s.
We measure a T90 of 12.92 (+8, -4) s from the cumulative Veto light
curve.
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.
CZTI GRB detections are reported regularly on the payload site at:
http://astrosat.iucaa.in/czti/?q=grb [1]
Links:
------
[1] http://astrosat.iucaa.in/czti/?q=grb