GRB 220910A
GCN Circular 32540
Subject
GRB 220910A: AGILE detection
Date
2022-09-10T10:01:59Z (3 years ago)
From
Alessandro Ursi at INAF/IAPS <alessandro.ursi@gmail.com>
A. Ursi, E. Menegoni (INAF/IAPS), M. Tavani (INAF/IAPS, and Univ. Roma Tor
Vergata), A. Argan, M. Cardillo, C. Casentini, Y. Evangelista, L. Foffano,
G. Piano (INAF/IAPS), A. Bulgarelli, A. Di Piano, V. Fioretti, G.
Panebianco, N. Parmiggiani (INAF/OAS-Bologna), F. Lucarelli, C. Pittori, F.
Verrecchia (SSDC, and INAF/OAR), M. Romani (INAF/OA-Brera), M. Marisaldi
(INAF/OAS-Bologna, and Bergen University), M. Pilia, A. Trois
(INAF/OA-Cagliari), I. Donnarumma (ASI), A. Giuliani (INAF/IASF-Mi), F.
Longo (Univ. Trieste and INFN Trieste), and P. Tempesta (TeleSpazio),
report on behalf of the AGILE Team:
The AGILE satellite detected the GRB 220910A at T0 = 2022-09-10 05:48:26 s
(UTC). The burst is clearly visible in the AGILE scientific ratemeters of
the MiniCALorimeter (MCAL; 0.4-100 MeV) and AntiCoincidence (AC; 50-200
keV) detectors. The event lasted about 3 s and it released a total number
of 8416 counts in the MCAL detector (above a background rate of 1310 Hz)
and 25992 counts in the AC detector (above a background rate of 4830 Hz).
The AGILE ratemeters light curves can be found at
http://www.agilescienceapp.it/notices/GRB220910A_AGILE_RM.png .
Additional analysis of AGILE data is in progress. Automatic MCAL GRB alert
Notices can be found at: https://gcn.gsfc.nasa.gov/agile_mcal.html.
GCN Circular 32541
Subject
GRB 220910A: AstroSat CZTI detection
Date
2022-09-10T19:34:14Z (3 years ago)
From
Gaurav Waratkar at IIT,Bombay <gauravwaratkar@iitb.ac.in>
R. Gopalakrishnan (IUCAA), V. Prasad (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 bright long GRB 220910A
which was also detected by AGILE (Ursi et al., GCN 32540) and reported
in an IPN_RAW notice (by Konus-Wind).
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
2022-09-10 05:48:29.0 UTC. The measured peak count rate associated with
the burst is 4111 (+341, -343) counts/s above the background in the
combined data of all quadrants, with a total of 5809 (+205, -203)
counts. The local mean background count rate was 503 (+6, -11) counts/s.
Using cumulative rates, we measure a T90 of 2.6 (+0.4, -0.3) s.
It was also clearly detected in the CsI anticoincidence (Veto) detector
in the 100-500 keV energy range. The light curve peaks at 2022-09-10
05:48:27.0 UTC. The measured peak count rate is 6301 (+143, -155)
counts/s above the background in the combined Veto data of all
quadrants, with a total of 14603 (+414, -431) counts. The local mean
background count rate was 1477 (+7, -8) counts/s. We measure a T90 of
3.7 (+0.5, -0.6) 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 32550
Subject
IPN triangulation of GRB 220910A (bright/long)
Date
2022-09-12T19:14:14Z (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. Goldstein, M. S. Briggs, and C. Wilson-Hodge
on behalf of the Fermi GBM team,
E. Bozzo and C. Ferrigno, on behalf of the INTEGRAL SPI-ACS GRB team,
report:
The very bright, long-duration GRB 220910A
(AGILE detection: Ursi et al., GCN Circ. 32540;
AstroSat-CZTI detection: Gopalakrishnan et al., GCN Circ. 32541)
was detected by AGILE (MCAL, AC), AstroSat (CZTI), Konus-Wind,
Fermi (GBM trigger 684481706), and INTEGRAL (SPI-ACS),
at about 20910 s UT (05:48:30).
We have triangulated it to a preliminary, 3 sigma error box
whose coordinates are:
---------------------------------------------
RA(2000), deg Dec(2000), deg
---------------------------------------------
Center:
8.124 (00h 32m 30s) -0.115 ( +0d 06' 55")
Corners:
9.094 (00h 36m 23s) -2.392 ( -2d 23' 30")
7.404 (00h 29m 37s) +2.183 ( +2d 11' 01")
7.046 (00h 28m 11s) +2.146 ( +2d 08' 44")
8.743 (00h 34m 58s) -2.426 ( -2d 25' 32")
---------------------------------------------
The error box area is 1.68 sq. deg, and its maximum
dimension is 4.98 deg (the minimum one is 20.6 arcmin).
The Sun distance was 160 deg.
This box may be improved.
The IPN localization is consistent with, but reduces the area of,
the Fermi-GBM final localization (glg_healpix_all_bn220910242_v00).
A triangulation map and HEALPix FITS file are posted at
http://www.ioffe.ru/LEA/GRBs/GRB220910_T20910/IPN/
The Konus-Wind time history and spectrum will be given in a forthcoming
GCN Circular.
GCN Circular 32551
Subject
GRB 220910A: Fermi GBM observation
Date
2022-09-12T19:17:35Z (3 years ago)
From
Christian Malacaria at ISSI <cmalacaria.astro@gmail.com>
C. Malacaria (ISSI) and C. Meegan (UAH)
report on behalf of the Fermi GBM Team:
"At 05:48:21.55 UT on 10 September 2022, the Fermi Gamma-Ray Burst Monitor (GBM)
triggered and located GRB 220910A (trigger 684481706 / 220910242),
which was also detected by AGILE (Ursi et al. 2022, GCN 32540)
and AstroSAT/CZTI (Gopalakrishnan et al. 2022, GCN 32541).
The on-ground calculated location, using the Fermi GBM trigger data,
is RA = 9.1, Dec = -1.1 (J2000 degrees, equivalent to
J2000 00h 32m, -01d 06'), with a statistical uncertainty of 1.0 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 at the GBM trigger time is 89 degrees.
The GBM light curve shows a precursor and a main, subsequent peak
with a duration (T90) of about 4 s (50-300 keV).
The time-averaged spectrum from T0-4.5 s to T0+10.6 s is
best fit by a Band function with Epeak = 357 +/- 8 keV,
alpha = -0.69 +/- 0.01, and beta = -2.51 +/- 0.06
The event fluence (10-1000 keV) in this time interval is
(4.69 +/- 0.03)E-05 erg/cm^2. The 1-sec peak photon flux measured
starting from T0+6.85 s in the 10-1000 keV band
is 76.9 +/- 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 <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/ <https://fermi.gsfc.nasa.gov/ssc/data/access/gbm/>"
GCN Circular 32555
Subject
Konus-Wind detection of GRB 220910A
Date
2022-09-13T15:16:11Z (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 very bright, long-duration GRB 220910A
(AGILE detection: Ursi et al., GCN Circ. 32540;
AstroSat-CZTI detection: Gopalakrishnan et al., GCN Circ. 32541;
IPN triangulaton: Svinkin et al., GCN Circ. 32550;
Fermi-GBM observation: Malacaria and Meegan, GCN Circ. 32551)
triggered Konus-Wind at T0=20910.521 s UT (05:48:30.521).
The burst light curve shows a multipeaked structure
which starts at ~T0-5.7 s and has a total duration of ~13.4 s.
The emission is seen up to ~16 MeV.
The Konus-Wind light curve of this GRB is available at
http://www.ioffe.ru/LEA/GRBs/GRB220910_T20910/
As observed by Konus-Wind, the burst
had a fluence of 5.23(-0.50,+0.53)x10^-5 erg/cm2,
and a 64-ms peak flux, measured from T0+2.112 s,
of 3.93(-0.47,+0.49)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+10.496 s)
is best fit in the 20 keV - 16 MeV range
by the GRB (Band) model with the following parameters:
the low-energy photon index alpha = -0.53(-0.14,+0.17),
the high energy photon index beta = -2.46(-0.29,+0.19),
the peak energy Ep = 310(-37,+39) keV
(chi2 = 110/97 dof).
The spectrum near the maximum count rate
(measured from T0+1.280 to T0+2.304 s)
is best fit in the 20 keV - 16 MeV range
by the GRB (Band) model with the following parameters:
the low-energy photon index alpha = -0.21(-0.19,+0.25),
the high energy photon index beta = -2.61(-0.27,+0.19),
the peak energy Ep = 254(-29,+30) keV
(chi2 = 72/59 dof).
All the quoted errors are at the 90% confidence level.
All the quoted values are preliminary.
GCN Circular 32559
Subject
Improved IPN error box for GRB 220910A
Date
2022-09-15T18:42:48Z (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 team,
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, and C. Wilson-Hodge
on behalf of the Fermi GBM team,
E. Bozzo and C. Ferrigno, on behalf of the INTEGRAL SPI-ACS GRB team,
report:
Using the BepiColombo (MGNS) data we have
triangulated GRB 220910A (GCNs 32540, 32541, 32550, 32551, 32555)
to an improved 3 sigma error box whose coordinates are:
---------------------------------------------
RA(2000), deg Dec(2000), deg
---------------------------------------------
Center:
8.734 (00h 34m 56s) -1.848 ( -1d 50' 54")
Corners:
8.884 (00h 35m 32s) -1.753 ( -1d 45' 11")
9.042 (00h 36m 10s) -2.231 ( -2d 13' 53")
8.584 (00h 34m 20s) -1.943 ( -1d 56' 35")
8.411 (00h 33m 39s) -1.432 ( -1d 25' 53")
---------------------------------------------
The error box area is 646 sq. arcmin, and its maximum
dimension is 1.019 deg (the minimum one is 19.44 arcmin).
The Sun distance was 159 deg.
This box may be further improved.
An updated triangulation map and HEALPix FITS file are posted at
http://www.ioffe.ru/LEA/GRBs/GRB220910_T20910/IPN/