GRB 200826B
GCN Circular 28292
Subject
GRB 200826B: Fermi GBM Final Real-time Localization
Date
2020-08-26T22:19:50Z (5 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 22:09:42 UT on 26 Aug 2020, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 200826B (trigger 620172587.721156 / 200826923).
The on-ground calculated location, using the Fermi GBM trigger data, is RA = 151.3, Dec = 51.7 (J2000 degrees, equivalent to J2000 10h 05m, 51d 42'), with a statistical uncertainty of 1.0 degrees.
The angle from the Fermi LAT boresight is 96.0 degrees.
The skymap can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2020/bn200826923/quicklook/glg_skymap_all_bn200826923.png
The HEALPix FITS file, including the estimated localization systematic, can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2020/bn200826923/quicklook/glg_healpix_all_bn200826923.fit
The GBM light curve can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2020/bn200826923/quicklook/glg_lc_medres34_bn200826923.gif
GCN Circular 28297
Subject
Fermi GRB 200826B: Global MASTER-Net observations report
Date
2020-08-27T19:18:52Z (5 years ago)
From
Vladimir Lipunov at Moscow State U/Krylov Obs <lipunov@xray.sai.msu.ru>
V. Lipunov, E. Gorbovskoy, V.Kornilov, N.Tyurina, P.Balanutsa, A.Kuznetsov, F.Balakin,
V.Vladimirov, D. Vlasenko, I.Gorbunov, D.Zimnukhov, V.Senik, T.Pogrosheva,
D.Kuvshinov, D. Cheryasov
(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, O.Ershova
(Irkutsk State University, API),
A. Tlatov, D. Dormidontov
(Kislovodsk Solar Station of the Pulkovo Observatory),
V. Yurkov, A. Gabovich, Yu. Sergienko
(Blagoveschensk Educational State University)
MASTER-Tavrida robotic telescope (Global MASTER-Net: http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L) located in Russia (Lomonosov MSU, SAI Crimea astronomical station) started inspect of the Fermi GRB 200826B ( Fermi GBM team, GCN 28292) errorbox 640 sec after notice time and 669 sec after trigger time at 2020-08-26 22:20:51 UT, with upper limit up to 16.4 mag. The observations began at zenith distance = 83 deg. The sun altitude is -35.3 deg.
The galactic latitude b = 51 deg., longitude l = 163 deg.
Real time updated cover map and OT discovered available here:
https://master.sai.msu.ru/site/master2/observ.php?id=1427827
We obtain a following upper limits.
Tmid-T0 | Date Time | Site | Coord (J2000) |Filt.| Expt. | Limit| Comment
_________|_____________________|_____________________|____________________________________|_____|_______|_______|________
734 | 2020-08-26 22:20:51 | MASTER-Tavrida | (10h 05m 19.01s , +51d 55m 00.9s) | C | 130 | 14.7 |
1129 | 2020-08-26 22:27:01 | MASTER-Tavrida | (10h 05m 18.37s , +51d 52m 53.7s) | C | 180 | 14.8 |
1558 | 2020-08-26 22:34:11 | MASTER-Tavrida | (10h 05m 22.98s , +51d 54m 35.8s) | C | 180 | 14.6 |
5955 | 2020-08-26 23:48:27 | MASTER-Tavrida | (10h 17m 44.99s , +52d 12m 40.0s) | C | 60 | 13.0 |
6197 | 2020-08-26 23:52:29 | MASTER-Tavrida | (09h 51m 23.97s , +50d 11m 34.2s) | C | 60 | 14.8 |
9451 | 2020-08-27 00:46:43 | MASTER-Tavrida | (10h 16m 17.78s , +50d 10m 53.5s) | C | 60 | 15.0 |
13932 | 2020-08-27 02:01:24 | MASTER-Tavrida | (10h 06m 27.15s , +54d 08m 38.9s) | C | 60 | 16.4 |
Filter C is a clear (unfiltred) band.
The observation and reduction will continue.
The message may be cited.
GCN Circular 28298
Subject
GRB 200826B: Fermi GBM detection
Date
2020-08-27T21:10:30Z (5 years ago)
From
Christian Malacaria at NASA-MSFC/USRA <cmalacaria@usra.edu>
C. Malacaria (NASA-MSFC/USRA) and C.Meegan (UAH)
report on behalf of the Fermi GBM Team:
"At 22:09:42.72 UT on 26 August 2020, the Fermi Gamma-Ray Burst Monitor (GBM)
triggered and located GRB 200826B (trigger 620172587 / 200826923).
The on-ground calculated location, using the GBM trigger
data, was reported in GCN 28292.
The GBM light curve shows an exceptionally bright long GRB
with a duration (T90) of about 7.4 s (50-300 keV).
The time-averaged spectrum from T0-0.003 s to T0+ 12.544 s is
best fit by a Band function with Epeak = 410.3 +/- 5.6 keV,
alpha = -0.64 +/- 0.01, and beta = -2.52 +/- 0.04
The event fluence (10-1000 keV) in this time interval is
(1.414 +/- 0.006)E-04 erg/cm^2.
The 1.024-sec peak photon flux measured starting from T0+5.1 s in
the 10-1000 keV band is 110.1 +/- 0.7 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 28303
Subject
IPN triangulation of GRB 200826B
Date
2020-08-28T19:31:31Z (5 years ago)
From
Dmitry Svinkin at Ioffe Institute <svinkin@mail.ioffe.ru>
K. Hurley, on behalf of the IPN,
I. G. Mitrofanov, D. V. Golovin, A. S. Kozyrev, M. L. Litvak,
and A. B. Sanin, on behalf of the HEND-Odyssey GRB team,
D. Svinkin, S. Golenetskii, R. Aptekar, D. Frederiks, A. Ridnaia,
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,
A. von Kienlin, X. Zhang, A. Rau, V. Savchenko, E. Bozzo,
and C. Ferrigno, on behalf of the INTEGRAL SPI-ACS GRB team,
and
W. Boynton, C. Fellows, K. Harshman, H. Enos, and R. Starr,
on behalf of the GRS-Odyssey GRB team, report:
The long-duration GRB 200826B
(Fermi-GBM detection: The Fermi GBM Team, GCN Circ. 28292;
Malacaria and Meegan, GCN Circ. 28298)
has been detected by Fermi (GBM trigger 620172587),
Konus-Wind, INTEGRAL (SPI-ACS), and Mars-Odyssey (HEND),
so far, at about 79779 s UT (22:09:39).
We have triangulated it to a preliminary, 3 sigma error box
whose coordinates are:
�� ---------------------------------------------
�� ��RA(2000), deg �� �� �� �� �� �� �� �� Dec(2000), deg
�� ---------------------------------------------
�� Center:
�� ��153.175 (10h 12m 42s) +57.580 (+57d 34' 48")
�� Corners:
�� ��154.647 (10h 18m 35s) +58.181 (+58d 10' 52")
�� ��153.503 (10h 14m 01s) +58.301 (+58d 18' 03")
�� ��151.749 (10h 07m 00s) +56.954 (+56d 57' 14")
�� ��152.864 (10h 11m 27s) +56.858 (+56d 51' 28")
�� ---------------------------------------------
The error box area is 3280 sq. arcmin, and its maximum
dimension is 2.0 deg (the minimum one is 33.4 arcmin).
The Sun distance was 47 deg.
This box may be improved.
The IPN localization is consistent with, but reduces the area of, the
Fermi RoboBA localization (GCN Circ. 28292).
A triangulation map is posted at
http://www.ioffe.ru/LEA/GRBs/GRB200826_T79779/IPN
The Konus-Wind time history and spectrum will be given in a forthcoming
GCN Circular.
GCN Circular 28304
Subject
Konus-Wind detection of GRB 200826B
Date
2020-08-28T20:46:49Z (5 years ago)
From
Anna Ridnaia at Ioffe Institute <ridnaia@mail.ioffe.ru>
A. Ridnaia, S. Golenetskii, R. Aptekar, D. Frederiks,
M. Ulanov, D. Svinkin, A. Tsvetkova, A. Lysenko, and T. Cline
on behalf of the Konus-Wind team, report:
The long-duration, very bright GRB 200826B
(Fermi-GBM detection: The Fermi GBM Team, GCN Circ. 28292;
Malacaria & Meegan, GCN Circ. 28298;
IPN triangulation: Hurley et al., GCN Circ. 28303)
triggered Konus-Wind at T0=79779.087 s UT (22:09:39.087).
The burst light curve shows a bright, multi-peaked pulse
which started at ~T0-3 s and had a total duration of ~23 s.
A weak post-burst emission is visible in the 18-70 keV band
up to the end of the KW trigger record at ~T0+250 s.
The emission is seen up to ~10 MeV.
The Konus-Wind light curve of this GRB is available at
http://www.ioffe.ru/LEA/GRBs/GRB200826_T79779/
As observed by Konus-Wind, the burst had
a fluence of (2.0 �� 0.1)x10^-4 erg/cm^2 and
a 64-ms peak energy flux, measured from T0+4.922,
of (4.8 �� 0.4)x10^-5 erg/cm^2/s
(both in the 20 keV - 10 MeV energy range).
The time-integrated spectrum of the burst
(measured from T0 to T0+17.408 s)
can be described, in the 20 keV - 15 MeV range,
by the GRB (Band) function with the following model parameters:
the low-energy photon index alpha = -0.54 (-0.04,+0.04),
the high energy photon index beta = -2.38 (-0.07,+0.06),
the peak energy Ep = 337 (-14,+15) keV,
chi2 = 169/96 dof.
The spectrum near the peak count rate
(measured from T0+4.864 to T0+5.120 s)
is best fit in the 20 keV - 15 MeV range by the GRB (Band)
function with the following model parameters:
the low-energy photon index alpha = -0.18 (-0.18,+0.22),
the high energy photon index beta = -2.42 (-0.23,+0.17),
the peak energy Ep = 320 (-45,+48) keV,
chi2 = 58/48 dof.
All the quoted errors are at the 90% confidence level.
All the quoted values are preliminary.