GRB 220927A
GCN Circular 32622
Subject
GRB220927A: Detection by GRBAlpha
Date
2022-10-04T15:32:59Z (3 years ago)
From
Jakub Ripa at Masaryk University <245487@mail.muni.cz>
A. Pal (Konkoly Observatory), J. Ripa, N. Werner (Masaryk U.), M. Ohno,
H. Takahashi (Hiroshima U.), L. Meszaros, B. Csak (Konkoly Observatory),
M. Dafcikova, N. Husarikova, J.-P. Breuer, F. Munz , M. Topinka, 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 220927A (Fermi-GBM detection: Fermi GBM Team, GCN
32594; IPN triangulation: Kozyrev et al., GCN 32597; Konus-Wind
detection: Ridnaia et al. GCN 32600) was detected by the GRBAlpha 1U
CubeSat (Pal et al. Proc. SPIE 2020).
The 19.7 sigma detection was confirmed at the peak time 2022-09-27
05:36:25.2 UTC. The GRB has the T90 duration of 8 s.
The light curve obtained by GRBAlpha is available here:
https://grbalpha.konkoly.hu/static/share/GRB220927A_GCN.pdf
GRBAlpha is a demonstration mission for a future CubeSats 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 about 50 keV to about 1000 keV. GRBAlpha was launched
on 2021 March 22 from Baikonur. After its commissioning phase, the
scientific observations are now under way. 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 32600
Subject
Konus-Wind detection of GRB 220927A
Date
2022-09-29T20:38:34Z (3 years ago)
From
Anna Ridnaia at Ioffe Institute <ridnaia@mail.ioffe.ru>
A.Ridnaia, D. Frederiks, A.Lysenko, D. Svinkin,
A. Tsvetkova, M. Ulanov, and T. Cline,
on behalf of the Konus-Wind team, report:
The long-duration GRB 220927A
(Fermi-GBM detection: Fermi GBM Team, GCN 32594;
IPN triangulation: Kozyrev et al., GCN 32597)
triggered Konus-Wind at T0=20180.364 s UT (05:36:20.364).
The burst light curve shows a multipeaked initial emission
episode which starts at ~T0-1.9 s and ends at ~T0+8.3 s,
followed by a weaker episode at ~T0+35 s.
The total burst duration is ~46.7 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/GRB220927_T20180/
As observed by Konus-Wind, the burst
had a fluence of 4.18(-1.08,+1.60)x10^-6 erg/cm2,
and a 64-ms peak flux, measured from T0+3.968 s,
of 9.37(-2.57,+2.78)x10^-7 erg/cm2/s
(both in the 20 keV - 10 MeV energy range).
The time-integrated spectrum of the burst
(measured from T0 to T0+41.216 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 = -1.37(-0.77,+2.06),
the high energy photon index beta = -2.60(-7.40,+0.35),
the peak energy Ep = 40(-22,+15) keV,
chi2 = 93/96 dof.
The spectrum near the maximum count rate
(measured from T0 to T0+8.448 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 = -0.97(-0.43,+0.61),
the high energy photon index beta = -3.04(-6.96,+0.44),
the peak energy Ep = 48(-6,+6) keV,
chi2 = 83/94 dof.
All the quoted errors are at the 90% confidence level.
All the quoted values are preliminary.
GCN Circular 32598
Subject
Fermi GRB 220927A: Global MASTER-Net observations report
Date
2022-09-27T22:45:17Z (3 years ago)
From
Vladimir Lipunov at Moscow State U/Krylov Obs <lipunov@xray.sai.msu.ru>
V. Lipunov, V.Kornilov, E.Gorbovskoy, K.Zhirkov, N.Tyurina, P.Balanutsa, A.Kuznetsov, D. Vlasenko,
G.Antipov, D.Zimnukhov, V.Senik, E.Minkina, A.Chasovnikov, V.Topolev, D.Kuvshinov, D.Cheryasov, Ya.Kechin
(Lomonosov Moscow State University, SAI, Physics Department),
R. Podesta, C.Lopez, F. Podesta, C.Francile
(Observatorio Astronomico Felix Aguilar OAFA),
R. Rebolo, M. Serra
(The Instituto de Astrofisica de Canarias),
D. Buckley
(South African Astronomical Observatory),
O.A. Gres, N.M. Budnev
(Irkutsk State University, API),
L.Carrasco, J.R.Valdes, V.Chavushyan, V.M.Patino Alvarez, J.Martinez, A.R.Corella, L.H.Rodriguez
(INAOE, Guillermo Haro Astrophysics Observatory),
A. Tlatov, D. Dormidontov
(Kislovodsk Solar Station of the Pulkovo Observatory),
A. Gabovich, V.Yurkov
(Blagoveschensk Educational State University)
MASTER-SAAO robotic telescope (Global MASTER-Net: http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L) located in South Africa (South African Astronomical Observatory) started inspect of the Fermi GRB 220927A ( Fermi GBM team, GCN 32594) errorbox 43499 sec after notice time and 61090 sec after trigger time at 2022-09-27 22:34:31 UT, with upper limit up to 17.4 mag. The observations began at zenith distance = 74 deg. The sun altitude is -56.2 deg.
The galactic latitude b = -17 deg., longitude l = 236 deg.
Real time updated cover map and OT discovered available here:
https://master.sai.msu.ru/site/master2/observ.php?id=2102352
We obtain a following upper limits.
Tmid-T0 | Date Time | Site | Coord (J2000) |Filt.| Expt. | Limit| Comment
_________|_____________________|_____________________|____________________________________|_____|_______|_______|________
61121 | 2022-09-27 22:34:31 | MASTER-SAAO | (06h 17m 38.05s , -29d 19m 22.8s) | C | 60 | 17.4 |
61203 | 2022-09-27 22:35:54 | MASTER-SAAO | (06h 26m 53.28s , -29d 18m 55.6s) | C | 60 | 17.1 |
Filter C is a clear (unfiltred) band.
The observation and reduction will continue.
The message may be cited.
GCN Circular 32597
Subject
IPN triangulation of GRB 220927A (long)
Date
2022-09-27T19:38:36Z (3 years ago)
From
Anna Ridnaia at Ioffe Institute <ridnaia@mail.ioffe.ru>
A.S. Kozyrev, D.V. Golovin, M.L. Litvak, I.G. Mitrofanov, and A.B. Sanin
on behalf of the HEND/Mars-Odyssey team,
A. Ridnaia, D. Frederiks, D. Svinkin, 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,
S. Barthelmy, J. Cummings, H. Krimm, D. Palmer, and A. Tohuvavohu
on behalf of the Swift-BAT 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 220927A
(Fermi-GBM detection: Fermi GBM Team, GCN 32594)
has been detected by Fermi (GBM trigger 685949785),
INTEGRAL (SPI-ACS), Konus-Wind, Mars-Odyssey (HEND),
and Swift (BAT), so far, at about 20180 s UT (05:36:20).
The burst was outside the coded field of view of the BAT.
We have triangulated it to a preliminary, 3 sigma error box
whose coordinates are:
---------------------------------------------
RA(2000), deg Dec(2000), deg
---------------------------------------------
Center:
90.969 (06h 03m 52s) -22.946 (-22d 56' 45")
Corners:
88.336 (05h 53m 21s) -23.483 (-23d 28' 59")
88.391 (05h 53m 34s) -23.818 (-23d 49' 04")
93.560 (06h 14m 14s) -22.267 (-22d 16' 00")
93.494 (06h 13m 59s) -21.929 (-21d 55' 45")
---------------------------------------------
The error box area is 1.68 sq. deg, and its maximum
dimension is 5.1 deg (the minimum one is 20 arcmin).
The Sun distance was 90 deg.
This box may be improved.
The IPN localization is consistent with, but reduces the area of, the
Fermi-GBM final localization (GCN 32594).
A triangulation map and HEALPix FITS file are posted at
http://www.ioffe.ru/LEA/GRBs/GRB220927_T20180/IPN
The time history and spectrum will be given in forthcoming GCN Circulars.
GCN Circular 32594
Subject
GRB 220927A: Fermi GBM Final Localization
Date
2022-09-27T14:39:49Z (3 years ago)
From
Joe Mangan at UCD <joseph.mangan@ucdconnect.ie>
The Fermi GBM team reports the detection of a likely Long GRB.
"At 05:36:20.95 UT on 27 September 2022, the Fermi Gamma-Ray Burst Monitor
(GBM) triggered and located GRB220927A (trigger 685949785 / 220927234).
The on-ground calculated location, using the GBM trigger data, is RA =
96.2, DEC = -22.5 (J2000 degrees, equivalent to 6h 24m, -22d 30'), with a
statistical uncertainty of 1 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 57
degrees.
The skymap can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2022/bn220927234/quicklook/glg_skymap_all_bn220927234.png
The HEALPix FITS file, including the estimated localization systematic, can
be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2022/bn220927234/quicklook/glg_healpix_all_bn220927234.fit
The GBM light curve can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2022/bn220927234/quicklook/glg_lc_medres34_bn220927234.gif