GRB 220203A
GCN Circular 31549
Subject
IPN triangulation of GRB 220203A (short)
Date
2022-02-04T23:00:29Z (3 years ago)
From
Dmitry Svinkin at Ioffe Institute <svinkin@mail.ioffe.ru>
D. Svinkin, D. Frederiks, A. Ridnaia, A. Lysenko,
and T. Cline on behalf of the Konus-Wind team,
A. von Kienlin, X. Zhang, A. Rau, V. Savchenko, E. Bozzo,
and C. Ferrigno, on behalf of the INTEGRAL SPI-ACS GRB team,
and
S. Barthelmy, J. Cummings, H. Krimm, D. Palmer, and A. Tohuvavohu
on behalf of the Swift-BAT team, report:
The short-duration GRB 220203A
has been detected by Konus-Wind, INTEGRAL (SPI-ACS), and
Swift (BAT), so far, at about 76530 s UT (21:15:30).
We have triangulated it to a preliminary, 3 sigma error box
whose coordinates are:
-----------------------
RA(2000) Dec(2000)
deg deg
-----------------------
Corners:
323.108 5.323
301.728 6.767
285.535 -7.425
301.509 7.331
------------------------
The error box area is 28.4 deg2, and its maximum
dimension is 39.6 deg (the minimum one is 47.5 arcmin).
The Sun distance was about 16 deg.
This box may be improved.
A triangulation map and HEALPix FITS file are posted at
http://www.ioffe.ru/LEA/GRBs/GRB220203_T76534/IPN/
The Konus-Wind time history and spectrum will be given in a forthcoming
GCN Circular.
GCN Circular 31550
Subject
GRB 220203A: Swift/BAT-GUANO detection outside the coded FOV
Date
2022-02-05T00:28:41Z (3 years ago)
From
Aaron Tohuvavohu at U Toronto <aaron.tohu@gmail.com>
Aaron Tohuvavohu (U Toronto), Gayathri Raman (PSU), James DeLaunay
(UAlabama), Jamie A. Kennea (PSU), report:
Swift/BAT did not localize GRB 220203A onboard (T0: 2022-02-03T21:15:39.8 UTC,
INTEGRAL #9677, IPN GCN 31549).
The INTEGRAL notice, 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 90 seconds of BAT event-mode data from [-45,+45]
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,
arXiv:2111.01769), detects the burst with a sqrt(TS) of 14.6 in a 0.256 s
analysis time bin.
The duration of the burst is ~0.3 seconds.
NITRATES results are consistent with a burst coming from outside the coded
FOV, with DeltaLLHOut of 4. An out of FOV origin is consistent with the IPN
localization (GCN 31549).
See Section 9.1 and Figure 20 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 31552
Subject
GRB 220203A: GECAM detection
Date
2022-02-05T14:58:40Z (3 years ago)
From
Zhao Yi at POLAR <yizhao@ihep.ac.cn>
Z. W. Guo, Y. Zhao, S. L. Xiong, J. C. Liu, Y. Q. Zhang, C. Y. Li, S. L. Xie,
S. Xiao, C. Cai, P. Zhang, X. Y. Zhao, Y. Huang, X. Y. Song,
C. Zheng, Y. Zhao, W. C. Xue, C. W. Wang,
Q. B. Yi, B. X. Zhang, W. X. Peng, R. Qiao, D. Y. Guo, X. B. Li,
X. Ma, L. M. Song, P. Wang, J. Wang, Z. Zhang, S. J. Zheng, W. Chen,
J. J. He, G. Y. Zhao, Y. Q. Du, H. Wu, J. Liang, Q. Luo, X. L. Zhang,
H. M. Zhang, Z. H. An, M. Gao, K. Gong, B. Li, C. Li, J. H. Li,
X. Q. Li, Y. G. Li, X. H. Liang, X. J. Liu, Y. Q. Liu, X. L. Sun,
Y. L. Tuo, J. Z. Wang, X. Y. Wen, Y. B. Xu, Y. P. Xu, S. Yang,
C. Y. Zhang, D. L. Zhang, Fan Zhang, Fei Zhang,
X. Zhou, F. J. Lu, S. N. Zhang (IHEP)
report on behalf of GECAM team:
During the commissioning phase, GECAM-B was triggered on ground by a short burst,
GRB 220203A, at 2022-02-03T21:15:39.750 UTC (denoted as T0), which has been
detected by Konus-Wind, INTEGRAL/SPI-ACS, and Swift/BAT.
GECAM alert data was downlinked to the ground through the short message
service of BeiDou Navigation Satellite System (BDS) within ~60 s after T0.
According to the BDS alert data, this burst mainly consists of a multiple pulses
with a duration of about 0.3 s.
The GECAM light curve could be found here:
http://twiki.ihep.ac.cn/pub/GECAM/GRBList/GRB220203A_lc.png
Using the automatic on-ground localization pipeline with the BDS alert data,
GECAM-B localized this burst to the following position (J2000):
Ra: 316.4 deg
Dec: 11.9 deg
Err: 13.3 deg (1-sigma, statistical only)
The current systematic error of location is estimated to be several degrees
which could be minimized by the ongoing calibration.
This position is consistent with the IPN localization (GCN 31549) within the error.
The GECAM preliminary location could be found here:
http://twiki.ihep.ac.cn/pub/GECAM/GRBList/GRB220203A_loc.png
Please note that all GECAM results here are preliminary. The final analysis
will be published in journal papers or GECAM online catalog.
Gravitational wave high-energy Electromagnetic Counterpart All-sky Monitor
(GECAM) mission consists of two small satellites (GECAM-A and GECAM-B) in
Low Earth Orbit (600 km, 29 deg), launched on Dec 10, 2020 (Beijing Time),
which was funded by the Chinese Academy of Sciences (CAS).
GCN Circular 31553
Subject
Konus-Wind detection of GRB 220203A
Date
2022-02-05T15:37:19Z (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 short-duration GRB 220203A
(IPN triangulation: Svinkin et al., GCN Circ. 31549;
Swift/BAT-GUANO detection: Tohuvavohu et al., GCN Circ. 31550;
GECAM detection: Guo et al., GCN Circ. 31552)
triggered Konus-Wind at T0=76534.783 s UT (21:15:34.783).
The burst light curve shows a multi-peaked structure
which starts at ~T0-0.1 s and has a total duration of ~0.3 s.
The emission is seen up to ~2 MeV.
The Konus-Wind light curve of this GRB is available at
http://www.ioffe.ru/LEA/GRBs/GRB220203_T76534/
As observed by Konus-Wind, the burst
had a fluence of 1.02(-0.26,+0.38)x10^-6 erg/cm2,
and a 16-ms peak flux, measured from T0-0.072 s,
of 8.81(-3.98,+5.24)x10^-6 erg/cm2/s
(both in the 20 keV - 10 MeV energy range).
The time-averaged spectrum of the burst
(measured from T0 to T0+0.256 s)
is best fit in the 20 keV - 5 MeV range
by a power law with exponential cutoff model:
dN/dE ~ (E^alpha)*exp(-E*(2+alpha)/Ep)
with alpha = -0.60(-0.52,+0.87)
and Ep = 408(-159,+377) keV (chi2 = 7/18 dof).
Fitting by a GRB (Band) model yields the same alpha and Ep,
and an upper limit on the high energy photon index: beta < -1.9
(chi2 = 8/17 dof).
All the quoted errors are at the 90% confidence level.
All the quoted values are preliminary.