GRB 210824A
GCN Circular 30730
Subject
GRB 210824A: Swift/UVOT Upper Limits
Date
2021-08-27T15:52:44Z (4 years ago)
From
Sam LaPorte at PSU <sjl5346@psu.edu>
GRB 210824A: Swift/UVOT Upper Limits
S. J. LaPorte (PSU) and K. L. Page (U. Leicester)
report on behalf of the Swift/UVOT team:
The Swift/UVOT began settled observations of the field of GRB 210824A
311 s after the BAT trigger (Page et al., GCN Circ. 30700).
No optical afterglow consistent with the XRT position
(Goad et al. GCN Circ. 30702)
is detected in the initial UVOT exposures.
Preliminary 3-sigma upper limits using the UVOT photometric system
(Breeveld et al. 2011, AIP Conf. Proc. 1358, 373) for the first
finding chart (FC) exposure and subsequent exposures are:
Filter T_start(s) T_stop(s) Exp(s) Mag
white_FC 311 461 147 >20.8
white 311 4350 364 >20.9
v 467 4760 236 >19.4
b 565 4145 235 >20.1
u 541 5220 83 >19.6
w1 516 5170 236 >20.4
m2 4765 4965 197 >20.3
w2 4356 4555 197 >19.9
The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.037 in the direction of the burst
(Schlegel et al. 1998).
GCN Circular 30722
Subject
GRB 210824A: Swift-BAT refined analysis
Date
2021-08-26T19:38:20Z (4 years ago)
From
Hans Krimm at NSF/NASA-GSFC <hkrimm@nsf.gov>
C. B. Markwardt (GSFC), S. D. Barthelmy (GSFC), H. A. Krimm (NSF),
S. Laha (GSFC/UMBC), A. Y. Lien (U Tampa), K. L. Page (U Leicester),
D. M. Palmer (LANL), T. Sakamoto (AGU), M. Stamatikos (OSU)
(i.e. the Swift-BAT team):
Using the data set from T-239 to T+963 sec from the recent telemetry downlink,
we report further analysis of BAT GRB 210824A (trigger #1070157)
(Page, et al., GCN Circ. 30700). The BAT ground-calculated position is
RA, Dec = 232.115, 11.169 deg which is
RA(J2000) = 15h 28m 27.5s
Dec(J2000) = +11d 10' 09.9"
with an uncertainty of 1.2 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 60%.
The mask-weighted light curve shows a single broad pulse with some sub-structure.
It begins around T-15 sec, peaks at the trigger time and decays to background by
T+40 sec. We note that the light curve has a gap from T+110 sec to T+240 sec due to the
burst going out of the field of view (for a pre-planned slew that started before the trigger
had been fully processed) and then coming back into FOV when the pre-planned slew ended
and the automated target slew had started. The burst appears to be over before this time.
T90 (15-350 keV) is 37.55 +- 4.79 sec (estimated error including systematics).
The time-averaged spectrum from T-13.70 to T+30.94 sec is best fit by a simple
power-law model. The power law index of the time-averaged spectrum is
1.18 +- 0.11. The fluence in the 15-150 keV band is 1.7 +- 0.1 x 10^-6 erg/cm2.
The 1-sec peak photon flux measured from T+1.02 sec in the 15-150 keV band
is 1.3 +- 0.2 ph/cm2/sec. All the quoted errors are at the 90% confidence
level.
The results of the batgrbproduct analysis are available at
http://gcn.gsfc.nasa.gov/notices_s/1070157/BA/
GCN Circular 30718
Subject
GRB 210824A: MITSuME Akeno optical upper limits
Date
2021-08-26T09:48:44Z (4 years ago)
From
Masafumi Niwano at Tokyo Institute of Tech <niwano@hp.phys.titech.ac.jp>
M. Niwano, K. L. Murata, R. Hosokawa, N. Ito, Y. Imai, H. Takamatsu, R.
Noto, S. Sato, M. Takaku, R. Yamaguchi, Y. Yatsu, and N. Kawai
(TokyoTech) report on behalf of the MITSuME collaboration:
We observed the field of GRB 210824A (Fermi GBM team, GCN Circular
#30699, K. L. Page et al. GCN Circular #30700, M.R. Goad et al. GCN
Circular #30702, V. D'Elia et al. GCN Circular #30704, X. Liu et al. GCN
Circular #30705, V. Lipunov et al. GCN Circular #30706, S. Lesage et al.
GCN Circular #30707, Y.-D. Hu et al. GCN Circular #30708, V. Lipunov et
al. GCN Circular #30709) with the optical three color (g', Rc, and Ic)
CCD cameras attached to the MITSuME 50 cm telescope Akeno. The
observation with a series of 60 sec exposures started at 2021-08-25
10:20:44 UT (30.1 hours after Fermi trigger). We stacked the images with
good conditions. We did not detect any uncatalogued sources within the
XRT error region (V. D'Elia et al. GCN Circular #30706). We obtained the
5-sigma limits of the stacked images as follows.
T0+[hour] MID-UT T-EXP[sec] 5-sigma limits
------------------------------------------------------------------------------------------------
31.3 2021-08-25 12:29:20.71 4740 g'>18.6, Rc>19.0, Ic>18.3
------------------------------------------------------------------------------------------------
T0+ : Elapsed time after the burst
T-EXP: Total Exposure time
We used PS1 catalog for flux calibration.
The magnitudes are expressed in the AB system.
The images were processed in real-time through the MITSuME GPU
reduction pipeline (Niwano et al. 2021, PASJ, Vol.73, Issue 1, Pages
4-24; https://github.com/MNiwano/Eclaire).
GCN Circular 30709
Subject
Swift GRB 210824A: Global MASTER-Net observations report
Date
2021-08-25T04:10:10Z (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-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) was pointed to the Swift GRB 210824A ( K. L. Page et al., GCN 30700) errorbox 45612 sec after notice time and 45332 sec after trigger time at 2021-08-24 16:50:54 UT, with upper limit up to 19.4 mag. Observations started at twilight. The observations began at zenith distance = 46 deg. The sun altitude is -7.8 deg.
MASTER-Tavrida robotic telescope located in Russia (Lomonosov MSU, SAI Crimea astronomical station) was pointed to the Swift GRB 210824A errorbox 48172 sec after notice time and 47892 sec after trigger time at 2021-08-24 17:33:34 UT, with upper limit up to 19.1 mag. Observations started at twilight. The observations began at zenith distance = 47 deg. The sun altitude is -10.9 deg.
MASTER-Kislovodsk robotic telescope located in Russia (Lomonosov MSU, Kislovodsk Solar Station of Pulkovo observatory) was pointed to the Swift GRB 210824A errorbox 50320 sec after notice time and 50041 sec after trigger time at 2021-08-24 18:09:23 UT, with upper limit up to 17.4 mag. The observations began at zenith distance = 56 deg. The sun altitude is -21.7 deg.
The galactic latitude b = 49 deg., longitude l = 17 deg.
Real time updated cover map and OT discovered available here:
https://master.sai.msu.ru/site/master2/observ.php?id=1698433
We obtain a following upper limits.
Tmid-T0 | Site |Filt.| Expt. | Limit| Comment
_________|_____________________|_____|_______|______|________
45363 | MASTER-SAAO | C | 60 | 16.0 |
45522 | MASTER-SAAO | C | 60 | 17.0 |
45602 | MASTER-SAAO | C | 60 | 17.2 |
46324 | MASTER-SAAO | C | 60 | 18.5 |
46483 | MASTER-SAAO | C | 60 | 18.7 |
46563 | MASTER-SAAO | C | 60 | 18.8 |
47281 | MASTER-SAAO | C | 60 | 19.4 |
47440 | MASTER-SAAO | C | 60 | 19.3 |
47520 | MASTER-SAAO | C | 60 | 19.4 |
47983 | MASTER-Tavrida | C | 180 | 17.8 |
49103 | MASTER-Tavrida | C | 180 | 19.1 |
49875 | MASTER-Tavrida | C | 60 | 18.7 |
50071 | MASTER-Kislovodsk | C | 60 | 15.8 |
50252 | MASTER-Tavrida | C | 180 | 19.0 |
50310 | MASTER-Kislovodsk | C | 180 | 15.1 |
50310 | MASTER-Kislovodsk | C | 180 | 15.3 |
51024 | MASTER-Tavrida | C | 60 | 18.4 |
51479 | MASTER-Tavrida | C | 60 | 18.4 |
51558 | MASTER-Tavrida | C | 60 | 18.4 |
52080 | MASTER-Kislovodsk | C | 60 | 16.6 |
52268 | MASTER-SAAO | C | 60 | 18.8 |
52527 | MASTER-Tavrida | C | 60 | 18.1 |
52605 | MASTER-Tavrida | C | 60 | 18.1 |
53102 | MASTER-Kislovodsk | C | 180 | 17.1 |
53102 | MASTER-Kislovodsk | C | 180 | 17.4 |
53227 | MASTER-SAAO | C | 60 | 18.6 |
53242 | MASTER-Kislovodsk | C | 60 | 17.0 |
53476 | MASTER-Tavrida | C | 60 | 17.9 |
53555 | MASTER-Tavrida | C | 60 | 17.9 |
54344 | MASTER-Kislovodsk | C | 180 | 17.0 |
54344 | MASTER-Kislovodsk | C | 180 | 17.1 |
54478 | MASTER-Tavrida | C | 180 | 18.0 |
54482 | MASTER-SAAO | C | 180 | 18.5 |
54617 | MASTER-Tavrida | C | 60 | 17.6 |
55565 | MASTER-SAAO | C | 180 | 17.0 |
55613 | MASTER-Tavrida | C | 180 | 17.8 |
55831 | MASTER-Tavrida | C | 60 | 17.5 |
56489 | MASTER-Kislovodsk | C | 60 | 12.8 |
56489 | MASTER-Kislovodsk | C | 60 | 14.0 |
56723 | MASTER-SAAO | C | 180 | 15.9 |
Filter C is a clear (unfiltred) band.
The observation and reduction will continue.
The message may be cited.
GCN Circular 30708
Subject
GRB 210824A: BOOTES-5/JGT optical upper limit
Date
2021-08-24T21:59:55Z (4 years ago)
From
Youdong HU at IAA-CSIC <huyoudong072@hotmail.com>
Y.-D. Hu, T.-R. Sun, E. Fernandez-Garcia, A. J. Castro-Tirado and M.D. Caballero-Garcia (IAA-CSIC), D. Hiriart, W. H. Lee (UNAM), C. J. Perez del Pulgar and I. Carrasco (UMA), I. H. Park (SKKU) on behalf of a larger collaboration, report:
The 60cm BOOTES-5/JGT robotic telescope at Observatorio Astronomico Nacional in San Pedro Martir (Mexico) automatically responded in 54 s to the Swift trigger of GRB 210824A (Page et al., GCNC 30700) , a burst which was also detected by Fermi (Fermi GBM team, GCNC 30699). In the co-added clear image (10 x 10 s), no optical afterglow is detected within the X-ray afterglow position (Page et al., GCNC 30700; Goad et al., GCNC 30702) down to 19.9 mag.
We thank the staff at Observatorio Astronomico Nacional in San Pedro Martir for its excellent support.
GCN Circular 30707
Subject
GRB 210824A: Fermi GBM Observation
Date
2021-08-24T19:45:52Z (4 years ago)
From
Stephen Lesage at Fermi-GBM Team <sjl0014@uah.edu>
S. Lesage (UAH) reports on behalf of the Fermi Gamma-ray Burst Monitor Team:
"At 04:10:03 UT on 24 August 2021, the Fermi Gamma-ray Burst Monitor (GBM)
triggered and located GRB 210824A (trigger 651471008/210824174)
which was also detected by Swift BAT (K. L. Page et al. 2021, GCN 30700).
The Fermi GBM Final Real-time Localization (GCN 30699) is consistent
with the Swift BAT position.
The angle from the Fermi LAT boresight is 75 degrees.
The GBM light curve consists of a single emission episode with a duration (T90)
of about 33 s (10-1000 keV). The time-averaged spectrum
from T0-0.6 to T0+28 s is best fit by
a power law function with an exponential high-energy cutoff.
The power law index is -1.2 +/- 0.1 and the cutoff energy,
parameterized as Epeak, is 552 +/- 286 keV.
The event fluence (10-1000 keV) in this time interval is
(5.3 +/- 0.6)E-06 erg/cm^2. The 1-sec peak photon flux measured
starting from T0+4.1 s in the 10-1000 keV band is 2.2 +/- 0.2 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 30706
Subject
Fermi GRB 210824A: Global MASTER-Net observations report
Date
2021-08-24T17:01:04Z (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-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 210824A ( Fermi GBM team, GCN 30699) errorbox 45625 sec after notice time and 45651 sec after trigger time at 2021-08-24 16:50:54 UT, with upper limit up to 17.2 mag. Observations started at twilight. The observations began at zenith distance = 46 deg. The sun altitude is -7.8 deg.
The galactic latitude b = 46 deg., longitude l = 19 deg.
Real time updated cover map and OT discovered available here:
https://master.sai.msu.ru/site/master2/observ.php?id=1698440
We obtain a following upper limits.
Tmid-T0 | Date Time | Site | Coord (J2000) |Filt.| Expt. | Limit| Comment
_________|_____________________|_____________________|____________________________________|_____|_______|_______|________
45682 | 2021-08-24 16:50:54 | MASTER-SAAO | (15h 30m 37.82s , +12d 36m 58.0s) | C | 60 | 16.0 |
45762 | 2021-08-24 16:52:14 | MASTER-SAAO | (15h 38m 47.90s , +12d 35m 22.7s) | C | 60 | 16.6 |
45841 | 2021-08-24 16:53:34 | MASTER-SAAO | (15h 24m 16.66s , +10d 42m 42.8s) | C | 60 | 17.0 |
45921 | 2021-08-24 16:54:54 | MASTER-SAAO | (15h 32m 23.86s , +10d 43m 21.8s) | C | 60 | 17.2 |
Filter C is a clear (unfiltred) band.
The observation and reduction will continue.
The message may be cited.
GCN Circular 30705
Subject
GRB 210824A: Nanshan/NEXT optical upper limit
Date
2021-08-24T16:06:10Z (4 years ago)
From
Dong Xu at NAOC/CAS <dxu@nao.cas.cn>
X. Liu, S.Y. Fu (NAOC), Z.P. Zhu (NAOC,HUST), D. Xu (NAOC), X. Gao
(Urumqi No.1 Senior High School), J.Z. Liu (XAO) report:
We observed the field of Swift GRB 210824A (Page et al. GCN Circ. 30700)
using the NEXT-0.6m telescope located at Nanshan, Xinjiang, China. We
obtained 10x200 s frames in the Sloan r-band, starting at 14:54:25 UT on
2021-08-24, i.e., 10.74 hr after the BAT trigger.
No optical source is detected in our stacked image at the enhanced
Swift/XRT position (Goad et al., GCN 30702), down to a limiting
magnitude of r~21.1, calibrated with the nearby PanSTARRS field.
GCN Circular 30704
Subject
GRB 210824A: Swift-XRT refined Analysis
Date
2021-08-24T15:28:01Z (4 years ago)
From
Phil Evans at U of Leicester <pae9@leicester.ac.uk>
V. D'Elia (SSDC & INAF-OAR), A. D'Ai (INAF-IASFPA), B. Sbarufatti
(PSU), D.N. Burrows (PSU), J. D. Gropp (PSU), A.P. Beardmore (U.
Leicester), P.A. Evans (U. Leicester), J.P. Osborne (U. Leicester), A.
Melandri (INAF-OAB) and K.L. Page report on behalf of the Swift-XRT
team:
We have analysed 6.6 ks of XRT data for GRB 210824A (Page et al. GCN
Circ. 30700), from 320 s to 28.9 ks after the BAT trigger. The data
are entirely in Photon Counting (PC) mode. The enhanced XRT position
for this burst was given by Goad et al. (GCN Circ. 30702).
The late-time light curve (from T0+3.9 ks) can be modelled with a
power-law decay with a decay index of alpha=0.94 (+0.25, -0.23).
A spectrum formed from the PC mode data can be fitted with an absorbed
power-law with a photon spectral index of 2.4 (+/-0.4). The
best-fitting absorption column is 6.8 (+3.1, -2.3) x 10^21 cm^-2, in
excess of the Galactic value of 3.3 x 10^20 cm^-2 (Willingale et al.
2013). The counts to observed (unabsorbed) 0.3-10 keV flux conversion
factor deduced from this spectrum is 3.6 x 10^-11 (8.4 x 10^-11) erg
cm^-2 count^-1.
A summary of the PC-mode spectrum is thus:
Total column: 6.8 (+3.1, -2.3) x 10^21 cm^-2
Galactic foreground: 3.3 x 10^20 cm^-2
Excess significance: 4.6 sigma
Photon index: 2.4 (+/-0.4)
If the light curve continues to decay with a power-law decay index of
0.94, the count rate at T+24 hours will be 2.4 x 10^-3 count s^-1,
corresponding to an observed (unabsorbed) 0.3-10 keV flux of 8.5 x
10^-14 (2.0 x 10^-13) erg cm^-2 s^-1.
The results of the XRT-team automatic analysis are available at
http://www.swift.ac.uk/xrt_products/01070157.
This circular is an official product of the Swift-XRT team.
GCN Circular 30702
Subject
GRB 210824A: Enhanced Swift-XRT position
Date
2021-08-24T11:40:54Z (4 years ago)
From
Phil Evans at U of Leicester <pae9@leicester.ac.uk>
M.R. Goad, J.P. Osborne, A.P. Beardmore and P.A. Evans (U. Leicester)
report on behalf of the Swift-XRT team.
Using 1505 s of XRT Photon Counting mode data and 3 UVOT
images for GRB 210824A, we find an astrometrically corrected X-ray
position (using the XRT-UVOT alignment and matching UVOT field sources
to the USNO-B1 catalogue): RA, Dec = 232.10583, +11.15351 which is equivalent
to:
RA (J2000): 15h 28m 25.40s
Dec (J2000): +11d 09' 12.6"
with an uncertainty of 2.4 arcsec (radius, 90% confidence).
This position may be improved as more data are received. The latest
position can be viewed at http://www.swift.ac.uk/xrt_positions. Position
enhancement is described by Goad et al. (2007, A&A, 476, 1401) and Evans
et al. (2009, MNRAS, 397, 1177).
This circular was automatically generated, and is an official product of the
Swift-XRT team.
GCN Circular 30700
Subject
GRB 210824A: Swift detection of a burst
Date
2021-08-24T04:35:52Z (4 years ago)
From
Kim Page at U.of Leicester <klp5@leicester.ac.uk>
K. L. Page (U Leicester), N. J. Klingler (GSFC/UMBC/CRESSTII),
H. A. Krimm (NSF), A. Y. Lien (U Tampa), M. H. Siegel (PSU) and
A. Tohuvavohu (U Toronto) report on behalf of the Neil Gehrels Swift
Observatory Team:
At 04:10:01 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 210824A (trigger=1070157). Swift slewed immediately to the burst.
The BAT on-board calculated location is
RA, Dec 232.132, +11.135 which is
RA(J2000) = 15h 28m 32s
Dec(J2000) = +11d 08' 07"
with an uncertainty of 3 arcmin (radius, 90% containment, including
systematic uncertainty). The BAT light curve showed a multi-peaked
structure with a duration of about 50 sec. The peak count rate
was ~1600 counts/sec (15-350 keV), at ~3 sec after the trigger.
The XRT began observing the field at 04:15:08.4 UT, 306.9 seconds after
the BAT trigger. Using promptly downlinked data we find a fading,
uncatalogued X-ray source located at RA, Dec 232.10513, 11.15208 which
is equivalent to:
RA(J2000) = 15h 28m 25.23s
Dec(J2000) = +11d 09' 07.5"
with an uncertainty of 7.2 arcseconds (radius, 90% containment). This
location is 113 arcseconds from the BAT onboard position, within the
BAT error circle. This position may be improved as more data are
received; the latest position is available at
https://www.swift.ac.uk/sper.
A power-law fit to a spectrum formed from promptly downlinked event
data gives a column density in excess of the Galactic value (3.31 x
10^20 cm^-2, Willingale et al. 2013), with an excess column of 8.5
(+5.30/-4.44) x 10^21 cm^-2 (90% confidence).
UVOT took a finding chart exposure of 150 seconds with the White filter
starting 310 seconds after the BAT trigger. No credible afterglow candidate has
been found in the initial data products. The 2.7'x2.7' sub-image covers none of
the XRT error circle. The 8'x8' region for the list of sources generated
on-board covers 100% of the XRT error circle. The list of sources is typically
complete to about 18 mag. No correction has been made for the expected
extinction corresponding to E(B-V) of 0.036.
Burst Advocate for this burst is K. L. Page (klp5 AT leicester.ac.uk).
Please contact the BA by email if you require additional information
regarding Swift followup of this burst. In extremely urgent cases, after
trying the Burst Advocate, you can contact the Swift PI by phone (see
Swift TOO web site for information: http://www.swift.psu.edu/)
GCN Circular 30699
Subject
GRB 210824A: Fermi GBM Final Real-time Localization
Date
2021-08-24T04:20:26Z (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 04:10:03 UT on 24 Aug 2021, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 210824A (trigger 651471008.06188 / 210824174).
The on-ground calculated location, using the Fermi GBM trigger data, is RA = 235.1, Dec = 10.4 (J2000 degrees, equivalent to J2000 15h 40m, 10d 24'), with a statistical uncertainty of 5.3 degrees.
The angle from the Fermi LAT boresight is 77.0 degrees.
The skymap can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2021/bn210824174/quicklook/glg_skymap_all_bn210824174.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/bn210824174/quicklook/glg_healpix_all_bn210824174.fit
The GBM light curve can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2021/bn210824174/quicklook/glg_lc_medres34_bn210824174.gif