GRB 210524A
GCN Circular 30071
Subject
GRB 210524A: Fermi GBM Final Real-time Localization
Date
2021-05-24T05:10:21Z (4 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 04:59:59 UT on 24 May 2021, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 210524A (trigger 643525204.091768 / 210524208).
The on-ground calculated location, using the Fermi GBM trigger data, is RA = 337.3, Dec = -47.0 (J2000 degrees, equivalent to J2000 22h 29m, -47d 00'), with a statistical uncertainty of 1.5 degrees.
The angle from the Fermi LAT boresight is 65.0 degrees.
The skymap can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2021/bn210524208/quicklook/glg_skymap_all_bn210524208.png
The HEALPix FITS file, including the estimated localization systematic, can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2021/bn210524208/quicklook/glg_healpix_all_bn210524208.fit
The GBM light curve can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2021/bn210524208/quicklook/glg_lc_medres34_bn210524208.gif
GCN Circular 30072
Subject
Fermi GRB 210524A: Global MASTER-Net observations report
Date
2021-05-24T05:32:00Z (4 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-IAC robotic telescope (Global MASTER-Net: http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L) located in Spain (IAC Teide Observatory) started inspect of the Fermi GRB 210524A ( Fermi GBM team, GCN 30071) errorbox 559 sec after notice time and 597 sec after trigger time at 2021-05-24 05:09:56 UT, with upper limit up to 17.0 mag. Observations started at twilight. The observations began at zenith distance = 81 deg. The sun altitude is -12.3 deg.
The galactic latitude b = -56 deg., longitude l = 348 deg.
Real time updated cover map and OT discovered available here:
https://master.sai.msu.ru/site/master2/observ.php?id=1620119
We obtain a following upper limits.
Tmid-T0 | Date Time | Site | Coord (J2000) |Filt.| Expt. | Limit| Comment
_________|_____________________|_____________________|____________________________________|_____|_______|_______|________
657 | 2021-05-24 05:09:56 | MASTER-IAC | (22h 28m 27.06s , -47d 09m 06.7s) | P| | 120 | 16.8 |
657 | 2021-05-24 05:09:56 | MASTER-IAC | (22h 27m 16.27s , -47d 03m 27.4s) | P- | 120 | 16.4 |
812 | 2021-05-24 05:12:16 | MASTER-IAC | (22h 28m 21.78s , -47d 10m 15.3s) | P| | 150 | 17.0 |
812 | 2021-05-24 05:12:16 | MASTER-IAC | (22h 27m 11.27s , -47d 04m 34.4s) | P- | 150 | 16.6 |
997 | 2021-05-24 05:15:06 | MASTER-IAC | (22h 28m 27.57s , -47d 09m 54.6s) | P| | 180 | 16.9 |
997 | 2021-05-24 05:15:06 | MASTER-IAC | (22h 27m 17.33s , -47d 04m 12.7s) | P- | 180 | 16.5 |
1197 | 2021-05-24 05:18:26 | MASTER-IAC | (22h 28m 24.64s , -47d 08m 43.0s) | P| | 180 | 16.7 |
1197 | 2021-05-24 05:18:26 | MASTER-IAC | (22h 27m 14.65s , -47d 03m 01.0s) | P- | 180 | 16.2 |
1397 | 2021-05-24 05:21:45 | MASTER-IAC | (22h 28m 24.73s , -47d 10m 02.6s) | P| | 180 | 16.4 |
1397 | 2021-05-24 05:21:45 | MASTER-IAC | (22h 27m 14.82s , -47d 04m 19.1s) | P- | 180 | 15.9 |
The observation and reduction will continue.
The message may be cited.
GCN Circular 30073
Subject
GRB 210524A: BALROG localization (Fermi Trigger 643525204 / GRB 210524208)
Date
2021-05-24T10:13:22Z (4 years ago)
From
Jochen Greiner at MPE,Garching <jcg@mpe.mpg.de>
B. Biltzinger, F. Kunzweiler, F. Berlato, J. Burgess & J. Greiner (all MPE Garching) report:
The public trigdat data of the Fermi Gamma-ray Burst Monitor (GBM) trigger
643525204 at 04:59:59 on 24 May 2021 were automatically fitted for spectrum
and sky location with BALROG (Burgess et al. 2018, MNRAS 476, 1427;
Berlato et al. 2019, ApJ 873, 60).
The best-fit position (1 sigma statistical errors) is:
RA(2000.0) = 343.2+/-0.7 deg
Decl.(2000.0) = -47.2+/-0.4 deg
We estimate an additional systematic error of 2 deg.
Further details are available at:
https://grb.mpe.mpg.de/grb/GRB210524208/
The Healpix map can be downloaded from:
https://grb.mpe.mpg.de/grb/GRB210524208/healpix
The location parameters are available as JSON at:
https://grb.mpe.mpg.de/grb/GRB210524208/json
GCN Circular 30076
Subject
IPN triangulation of GRB 210524A
Date
2021-05-25T10:03:18Z (4 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, 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,
A. von Kienlin, X. Zhang, A. Rau, V. Savchenko, 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, and R. Starr,
on behalf of the GRS-Odyssey GRB team, report:
The intense, long-duration GRB 210524A
(Fermi-GBM detection: The Fermi GBM team, GCN Circ. 30071;
BALROG localization: Biltzinger et al., GCN Circ. 30073)
was detected by Fermi (GBM trigger 643525204), Konus-Wind,
Mars-Odyssey (HEND), INTEGRAL (SPI-ACS), and Swift-BAT
at about 17999 s UT (04:59:59).
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:
343.564 (22h 54m 15s) -46.672 (-46d 40' 19")
Corners:
342.645 (22h 50m 35s) -49.867 (-49d 52' 00")
344.262 (22h 57m 03s) -43.354 (-43d 21' 13")
344.203 (22h 56m 49s) -43.132 (-43d 07' 56")
342.607 (22h 50m 26s) -49.680 (-49d 40' 48")
---------------------------------------------
The error box area is 1584 sq. arcmin, and its maximum
dimension is 6.8 deg (the minimum one is 4 arcmin).
The Sun distance was 95 deg.
This box may be improved.
The IPN localization is consistent with, but reduces the area of, the
Fermi RoboBA and BALROG localizations (GCN Circ. 30071 and 30073).
A triangulation map is posted at
http://www.ioffe.ru/LEA/GRBs/GRB210524_T18010/IPN/
The Konus-Wind time history and spectrum will be given in a forthcoming
GCN Circular.
GCN Circular 30077
Subject
Konus-Wind detection of GRB 210524A
Date
2021-05-25T16:04:23Z (4 years ago)
From
Dmitry Svinkin at Ioffe Institute <svinkin@mail.ioffe.ru>
D. Svinkin, S. Golenetskii, D. Frederiks, M. Ulanov,
A. Tsvetkova, A. Lysenko, A. Ridnaia, and T. Cline
on behalf of the Konus-Wind team, report:
The long-duration GRB 210524A
(Fermi-GBM detection: The Fermi GBM team, GCN Circ. 30071;
IPN triangulation: Hurley et al., GCN Circ. 30076)
triggered Konus-Wind at T0=18010.925 s UT (05:00:10.925).
The burst light curve shows a multi-peaked structure
which starts at ~T0-3.5 s and has a total duration of ~11.5 s.
The emission is seen up to ~1 MeV.
The Konus-Wind light curve of this GRB is available at
http://www.ioffe.ru/LEA/GRBs/GRB210524_T18010/
As observed by Konus-Wind, the burst
had a fluence of 8.64(-0.52,+0.56)x10^-6 erg/cm2,
and a 64-ms peak flux, measured from T0+2.752 s,
of 3.76(-1.00,+1.00)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+8.448 s)
is best fit in the 20 keV - 2 MeV range
by a power law with exponential cutoff model:
dN/dE ~ (E^alpha)*exp(-E*(2+alpha)/Ep)
with alpha = -1.33(-0.19,+0.20)
and Ep = 99(-10,+11) keV (chi2 = 45/56 dof).
Fitting by a GRB (Band) model yields the same alpha and Ep,
and an upper limit on the high energy photon index: beta < -2.7
(chi2 = 45/55 dof).
All the quoted errors are at the 90% confidence level.
All the quoted values are preliminary.