TITLE: GCN CIRCULAR
NUMBER: 36719
SUBJECT: GRB 240619A: CALET Gamma-Ray Burst Monitor detection
DATE: 24/06/21 07:03:46 GMT
FROM: Yuta Kawakubo at Aoyama Gakuin University <kawakubo(a)phys.aoyama.ac.jp>
S. Torii (Waseda U), A. Yoshida, T. Sakamoto, S. Sugita, Y. Kawakubo (AGU),
K. Yamaoka (Nagoya U), S. Nakahira (JAXA), Y. Asaoka (ICRR),
Y. Akaike, K. Kobayashi (Waseda U), Y. Shimizu, T. Tamura (Kanagawa U),
N. Cannady (GSFC/UMBC), M. L. Cherry (LSU), S. Ricciarini (U of Florence),
P. S. Marrocchesi (U of Siena),
and the CALET collaboration:
The long GRB 240619A (Fermi GBM Final Real-time Localization: Fermi GBM team,
GCN Circ. 36694; BALROG localization: Preis et al., GCN Circ. 36695; Fermi GBM
Observation: Dalessi et al., GCN Circ. 36717) triggered the CALET Gamma-ray
Burst Monitor (CGBM) at 03:43:30.40 UTC on 19 June 2024
(https://cgbm.calet.jp/cgbm_trigger/flight/1402803348/index.html).
The burst signal was seen by all CGBM detectors.
The burst light curve shows a double-peaked structure that starts
at T+0.6 sec, peaks at T+1.1 sec, and ends at T+37.4 sec.
The T90 and T50 durations measured by the SGM data are 35.0 +/- 1.3 sec
and 28.5 +/- 1.1 sec (40-1000 keV), respectively.
The ground-processed light curve is available at
https://cgbm.calet.jp/cgbm_trigger/ground/1402803348/
The CALET data used in this analysis are provided by
the Waseda CALET Operation Center located at Waseda University.
View this GCN Circular online at https://gcn.nasa.gov/circulars/36719.
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TITLE: GCN CIRCULAR
NUMBER: 36718
SUBJECT: GRB 240619C: NuSTAR automated detection of the GRB
DATE: 24/06/21 01:24:49 GMT
FROM: Brian Grefenstette at Caltech/NuSTAR <bwgref(a)srl.caltech.edu>
B. Grefenstette (Caltech) reports on behalf of the NuSTAR Search for INteresting Gamma-ray Signals (SINGS) working group:
The NuSTAR SINGS working group reports the detection of prompt emission from the Long GRB 240619C in both the NuSTAR CsI anti-coincidence shields. This GRB was identified through a blind search using the CsI shield rates. Details of the search algorithm will be described in a future paper.
The NuSTAR SINGS algorithm triggered at 2024-06-19 23:44:46 (with a resolution ~5-seconds). This is consistent with the Astrosat CTZI detection (Waratkar et al, GCN circ. 36711). Using the GRB X-ray localization from Fermi (Bala, et al., GCN Circ. 36716), we estimate that the GRB was above the Earth’s horizon as seen by NuSTAR and roughly 20-deg from the telescope boresight.
The NuSTAR CsI shield data are recorded at 1 Hz. The GRB appears to be composed of multiple short, unresolved peaks superposed on broader emission. We estimate the duration at ~20-25-s, but the low overall SNR of the GRB emission makes an accurate estimate of T90 unfeasible. The shield rates are typically around 1,500 - 2,000 cps throughout the burst (typical background rates are 1,000 cps).
We confirmed that there was no significant solar activity during this period that may also produce transients in the CsI shields.
Lightcurves and analysis for this GRB can be found here:
https://nustarsoc.caltech.edu/NuSTAR_Public/grbs/reports/2024/240619C/
Information on NuSTAR SINGS can be found here:
https://nustarsoc.caltech.edu/NuSTAR_Public/grbs/
NuSTAR is a NASA Small Explorer mission led by Caltech and managed by JPL for NASA’s Science Mission Directorate in Washington.
View this GCN Circular online at https://gcn.nasa.gov/circulars/36718.
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TITLE: GCN CIRCULAR
NUMBER: 36717
SUBJECT: GRB 230619A: Fermi GBM Observation
DATE: 24/06/21 01:21:25 GMT
FROM: Sarah Dalessi at UAH <sd0104(a)uah.edu>
S. Dalessi (UAH) and C. Meegan (UAH) report on behalf of
the Fermi Gamma-ray Burst Monitor Team:
"At 03:43:31.00 UT on 19 June 2024, the Fermi Gamma-ray Burst Monitor (GBM)
triggered and located GRB 240619A (trigger 740461416/240619155), which was also
detected by the Gravitational-wave Optical Transient Observer (GOTO) (Gompertz et al. 2024, GCN 36715).
The Fermi-GBM Final Real-time location (Fermi GBM Team 2024, GCN 36694)
is consistent with the GOTO position.
The angle from the Fermi LAT boresight is 63 degrees.
The GBM light curve two emission episodes with a duration (T90)
of about 36.1 s (50-300 keV). The time-averaged spectrum
from T0+0.002 to T0+36.129 s is best fit by
a Band function with Epeak = 110 +/- 50 keV,
alpha = -1.3 +/- 0.2, and beta = -1.70 +/- 0.04.
The event fluence (10-1000 keV) in this time interval is
(1.19 +/- 0.03)E-05 erg/cm^2. The 1-sec peak photon flux measured
starting from T0+0.096 s in the 10-1000 keV band is 19.1 +/- 0.4 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/"
View this GCN Circular online at https://gcn.nasa.gov/circulars/36717.
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TITLE: GCN CIRCULAR
NUMBER: 36716
SUBJECT: Fermi GBM Sub-Threshold Detection of GRB 240619C
DATE: 24/06/20 21:16:24 GMT
FROM: sumanbala2210(a)gmail.com
S. Bala (USRA) reports on behalf of the Fermi-GBM Team:
AstroSat CZTI detected GRB 240619C at 2024-06-19 23:44:51.50 UTC (GCN 36711).
There was a Fermi-GBM onboard accidental trigger around 420s before GRB 240619C.
Due to the Fermi-GBM trigger latency, we were unable to trigger immediately on the GRB.
The GRB 240619C can be partially seen in the trigger data (trigger 740533060 / 240619984).
The on-ground calculated location, using the Fermi GBM trigger data,
is RA = 340.68, Dec = -71.85 (J2000 degrees, equivalent to
J2000 22h 43m, -71d 51'), with a statistical uncertainty of 1.15 degrees.
The angle from the Fermi LAT boresight is 56 degrees.
The GBM targeted search [1], the most sensitive, coherent search for
GRB-like signals, was used to identify GRB-like emission episodes at around the AstroSAT GCN time. We find multiple emission peaks, each with a localization consistent with the on-ground localization from the Trigdat data. The brightest peak (at Fermi MET 740533496.5 s) was
found to be the most significant (S/N of 15) on the 2.048 s timescale, with a false alarm rate of 5.4e-06 Hz, using the standard search protocol. The GBM targeted search found this
brightest peak to have a "hard" GRB spectrum (Cut-off Power Law function with Epeak=1500 keV, alpha = -1.5 )
[1] Goldstein et al. 2019 arXiv:1903.12597
View this GCN Circular online at https://gcn.nasa.gov/circulars/36716.
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TITLE: GCN CIRCULAR
NUMBER: 36715
SUBJECT: GRB 240619A: GOTO candidate optical afterglow
DATE: 24/06/20 21:07:53 GMT
FROM: Ben Gompertz at U of Birmingham <b.gompertz(a)bham.ac.uk>
B. P. Gompertz, K. Ackley, S. Belkin, T. Killestein, A. J. Levan, B. Godson, R. Starling, M. J. Dyer, J. Lyman, K. Ulaczyk, F. Jimenez-Ibarra, A. Kumar, D. O'Neill, D. Steeghs, D. K. Galloway, V. Dhillon, P. O'Brien, G. Ramsay, K. Noysena, R. Kotak, R. P. Breton, L. K. Nuttall, E. Pall'e and D. Pollacco report on behalf of the GOTO collaboration:
We report on observations with the Gravitational-wave Optical Transient Observer (GOTO; Steeghs et al. 2022) in response to GRB 240619A (Fermi GBM Team, GCN 36694). Targeted observations were performed by GOTO-South at 08:21:34 UT on 2024-06-19 (3x90s exposures, 4.7 hours after trigger), and by GOTO-North at 21:40:50 UT on 2024-06-19 (4x90s exposures, 18.0 hours after trigger). Observations were taken in the GOTO L-band (400-700 nm).
Images were processed immediately after acquisition using the GOTO pipeline. Difference imaging was performed using recent survey observations of the same pointings. Source candidates were initially filtered using a classifier (Killestein et al. 2021) and cross-matched against a variety of contextual and minor planet catalogues. Human vetting was carried out in real time on any candidates that passed the above checks.
A new optical source AT 2024lwv<https://www.wis-tns.org/object/2024lwv> (GOTO24cvn) is identified within the GBM 90% localisation region at RA = 10:49:34.70, Dec = +17:16:58.07 with an initial magnitude of L = 17.17 +/- 0.17 mags 4.7 hours after trigger, fading to L = 18.38 +/- 0.09 mags at 18.0 hours after trigger. The source is also present in the data available on the ATLAS forced photometry server (Shingles et al. 2021) with an initial magnitude of o = 16.2 +/- 0.04, 2.3 hours after the GRB trigger. Observations are consistent with a power-law decay of approximately t^-0.8. The transient was not detected in the most recent pre-trigger GOTO observation, taken at 21:54:02 UT on 2024-06-17 (~1.25 days prior to the GRB) to a 5-sigma limiting magnitude of L > 19.2 mags.
The transient is spatially coincident (0.1” offset) with the catalogued galaxy PSO J162.3946+17.2828 with a photometric redshift of 0.63 +/- 0.19 in the PS1-STRM catalogue (Beck et al. 2020). Due to the galaxy association, rapid decay, and lack of detection in pre-GRB imaging, we propose this source as the optical afterglow of GRB 240619A.
Magnitudes were calibrated using ATLAS-REFCAT2 (Tonry et al. 2018) and are not corrected for Galactic extinction.
Observations are ongoing.
GOTO (https://goto-observatory.org) is a network of telescopes that is principally funded by the STFC and operated at the Roque de los Muchachos Observatory on La Palma, Spain, and Siding Spring Observatory in NSW, Australia, on behalf of a consortium including the University of Warwick, Monash University, Armagh Observatory & Planetarium, the University of Leicester, the University of Sheffield, the National Astronomical Research Institute of Thailand (NARIT), the University of Turku, the University of Portsmouth, the University of Manchester and the Instituto de Astrofisica de Canarias (IAC).
View this GCN Circular online at https://gcn.nasa.gov/circulars/36715.
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TITLE: GCN CIRCULAR
NUMBER: 36714
SUBJECT: EP240618a: Abastumani optical observationsEP240618a
DATE: 24/06/20 17:11:44 GMT
FROM: XXXX at IKI <alex(a)cgrsmx.iki.rssi.ru>
N. Pankov (HSE, IKI), A. Pozanenko (IKI), R. Ya. Inasaridze (AbAO) report on behalf of GRB-IKI-FuN collaboration:
We observed the refined error circle of EP240618a (Sun et al., GCN 36690) with AS-32 telescope of Abastumani Observatory (AbAO) equipped with CCD photometer and the R-filter to search for an optical counterpart. The observations were taken on dates 2024-06-18 and 2024-06-19. The first series is consist of 66x60 sec images, while latter one is 120x60 sec. Using image differencing, we find no new source within the localization circle or any brightness excess of catalog sources. The obtained results are consistent with observations by other telescopes (Wu et al., GCN 36701; Adami et al., GCN 36702; Tinyanont et al., GCN 36710; Akl et al., GCN 36712). Preliminary upper limits are following:
Date UT start t-T0 Exp. Filter OT Err. UL(3 sigma)
(mid, days) (s)
2024-06-18 18:18:51 0.524398 64x60 R n/d n/d 19.6
2024-06-19 21:45:02 1.667581 120x60 R n/d n/d 20.1
The difference image has an upper limit of 19.9 mag. The magnitudes were calibrated using nearby stars from USNO-B1.0 (R2 magnitude) catalog. The magnitudes are not corrected for the Galactic extinction towards EP240618a, which is A(V) = 0.4294 mag (S&F 2011).
View this GCN Circular online at https://gcn.nasa.gov/circulars/36714.
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TITLE: GCN CIRCULAR
NUMBER: 36713
SUBJECT: GRB 240615A: NOT optical observations
DATE: 24/06/20 13:43:59 GMT
FROM: Dong Xu at NAOC/CAS <dxu(a)nao.cas.cn>
S.Q. Jiang, S.Y. Fu, X. Liu (NAOC), D. B. Malesani (DAWN/NBI and Radboud Univ.), Z.P. Zhu, J. An, D. Xu (NAOC), B. Gompertz (Birmingham), M. A. Diaz Teodori (NOT), report on behalf of a large collaboration:
We observed the Swift/BAT-GUANO field of GRB 240615A detected by Fermi/GBM (Fermi GBM team, GCN 36671), Swift/BAT-GUANO (DeLaunay et al., GCN 36672), Konus-Wind (Frederiks et al., GCN 36677) and GECAM (Tan et al., GCN 36682) using the 2.56-m Nordic Optical Telescope (NOT) equipped with the ALFOSC camera.
Observations were carried out in the r band on 2024-06-16 and in the r and z bands on 2024-06-20. A red optical source is detected in the z-band of the second NOT epoch at the Wendelstein position (Busmann et al., GCN GCN 36706), which is consistent with the XRT Source #1 position (Page et al., GCN 36683). Preliminary photometry for the optical transient is as follows:
Tmid(UT) Tmid-T0(hr) Mag MagErr UL(5-sigma) Filter
2024-06-16T03:50:07 9.98 - - >23.9 r
2024-06-20T01:23:48 103.53 - - >22.8 r
2024-06-20T01:41:45 103.83 21.95 0.14 - z
calibrated against nearby Pan-STARRS stars and not corrected for Galactic extinction.
Photometry of the Pan-STARRS archival images yields r > 23.2 (5-sigma) and z > 22.1 (5-sigma). We notice that the NOT z-band magnitude is not significantly brighter than the Pan-STARRS limit, hence our data alone do not allow to robustly claim the detection of a new source.
View this GCN Circular online at https://gcn.nasa.gov/circulars/36713.
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TITLE: GCN CIRCULAR
NUMBER: 36712
SUBJECT: EP240618a: GRANDMA Optical Upper Limits
DATE: 24/06/20 09:24:27 GMT
FROM: Dalya Akl at American Uni. SHJ <dalyaakl.d(a)gmail.com>
D. Akl (AUS), M. Masek (FZU), C. Andrade (UMN), E. G. Elhosseiny (NRIAG), H. Peng (THU), L. Wang (XAO), S. Antier (OCA), S. Karpov (FZU), M. Coughlin (UMN), I. Tosta e Melo (UniCT-DFA), P. Hello (IJCLAB), P-A Duverne (APC), D. Turpin (CEA-Saclay/Irfu), N. Guessoum (AUS), T. Pradier (Unistra/IPHC), J.-G. Ducoin (CPPM), M. Prouza (FZU), A. Klotz (CNRS-OMP-IRAP), M. Boer, A. S. Gervasoni, C. Limonta (OCA), Y.Rajabov, O.Burkhonov (UBAI), Y.Tillayev, S.Ehgamberdiev (UBAI, NUUz), T.Sadibekova (UBAI-CEA), M. Freeberg (KNC), M. Serrau (KNC), M. Odeh (AKO), C. Galdies (KNC), A. LeCalloch (Berkeley), N. Leroy (IJCLAB) on behalf of the GRANDMA collaboration:
We performed observations with GRANDMA and its citizen science project Kilonova-catcher (KNC) on the X-ray transient EP240618a detected by Einstein Probe (EP) WXT on T0 = 2024-06-18T05:43:43 (GCN 36690). We monitored the source with 8 telescopes, including TAROT-TCH, TAROT-TCA, FRAM-CTA-N, and UBAI-NT60, from 2024-06-18T16:10:05 to 2024-06-19T09-57-01 UTC, starting 0.43 days after the EP trigger.
We did not find any new optical counterpart in any of our frames within 30 arcsec radius centered around Ra/Dec: 281.648/ 23.833 deg, consistent with the reports from (Tinyanont et al., GCN 36710; Adami et al., GCN 36702; Wu et al., GCN 36701).
All our observations and upper limits, which correspond to the depth of the full image (given in the AB system), can be found here:
https://skyportal-icare.ijclab.in2p3.fr/public/sources/EP240618a/version/8f…
Below is the version that can be downloaded from the link above:
+--------------+----------+----------------+-------------------+
| MJD | Filter | Lim.Mag | Instrument |
+==============+==========+================+===================+
| 60479.687743 | I | 18.96 | UBAI/NT-60 |
+--------------+----------+----------------+-------------------+
| 60479.942361 | sdssg | 17.82 | TAROT/TCA |
+--------------+----------+----------------+-------------------+
| 60479.942361 | sdssg | 17.83 | TAROT/TCH |
+--------------+----------+----------------+-------------------+
| 60479.912306 | R | 17.97 | FRAM-CTA-N |
+--------------+----------+----------------+-------------------+
| 60480.406678 | R | 19.29 | KNC |
+--------------+----------+----------------+-------------------+
| 60479.993831 | V | 20.26 | KNC |
+--------------+----------+----------------+-------------------+
| 60479.759005 | I | 19.54 | KNC |
+--------------+----------+----------------+-------------------+
| 60479.683044 | R | 19.54 | KNC |
+--------------+----------+----------------+-------------------+
| 60480.027174 | sdssg | 20.15 | KNC |
+--------------+----------+----------------+-------------------+
| 60479.983422 | sdssr | 19.93 | KNC |
+--------------+----------+----------------+-------------------+
| 60479.664595 | V | 19.65 | KNC |
+--------------+----------+----------------+-------------------+
| 60479.949853 | G | 20.40 | KNC |
+--------------+----------+----------------+-------------------+
We note that in the Skyportal page above, bessellv, bessellr, and besselli filters correspond to V, R, and I Johnson Cousin filters, respectively.
Generic telescopes in the Skyportal page correspond to KNC telescopes.
All the data have been reduced by a single data processing pipeline STDPIPE (Karpov et al., 2022).
Images obtained in Johnson Cousin filters were calibrated using the Gaia DR3 Synphot catalog while images taken with Sloan filters were calibrated using the Pan-STARRS DR1 Catalog.
We note that some amateur telescopes use green filters, which were calibrated with the Gaia catalog.
We use the Skyportal application (skyportal.io) to monitor our observational campaign.
We thank the Einstein Probe team for useful communication.
GRANDMA is a worldwide telescope network (https://grandma.lal.in2p3.fr/) devoted to the observation of transients in the context of multi-messenger astrophysics (Antier et al. 2020 MNRAS 497, 5518). Kilonova-Catcher (KNC) is the citizen science program of GRANDMA (http://kilonovacatcher.in2p3.fr/).
View this GCN Circular online at https://gcn.nasa.gov/circulars/36712.
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TITLE: GCN CIRCULAR
NUMBER: 36711
SUBJECT: GRB 240619C: AstroSat CZTI detection
DATE: 24/06/20 05:56:11 GMT
FROM: Gaurav Waratkar at IIT Bombay <gauravwaratkar(a)iitb.ac.in>
J. Joshi (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 long-duration GRB 240619C. Inspection of INTEGRAL/SPI-ACS data also showed the detection of the burst.
The source was clearly detected in the CZT detectors in the 20-200 keV energy range. The light curve showed multiple peaks of emission with the strongest peak at 2024-06-19 23:44:51.50 UTC. The measured peak count rate associated with the burst is 186 (+34, -37) counts/s above the background in the combined data of three quadrants (out of four), with a total of 694 (+196, -209) counts. The local mean background count rate was 268 (+3, -4) counts/s. Using cumulative rates, we measure a T90 of 17 (+1, -5) s.
The source was also clearly detected in the CsI anticoincidence (Veto) detector in the 100-500 keV energy range. The light curve showed multiple peaks of emission with the strongest peak at 2024-06-19 23:44:51.11 UTC. The measured peak count rate associated with the burst is 1471 (+90, -96) counts/s above the background in the combined data of all quadrants, with a total of 5520 (+402, -429) counts. The local mean background count rate was 1481 (+7, -8) counts/s. We measure a T90 of 14 (+1, -1) s from the cumulative Veto light curve.
Note that we see an additional peak in INTEGRAL/SPI-ACS data about 70 s after the main episode of this GRB. These peaks are very faint in our data; hence, we do not include them in our T90 calculations.
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.
CZTI GRB detections are reported regularly on the payload site at:
http://astrosat.iucaa.in/czti/?q=grb
View this GCN Circular online at https://gcn.nasa.gov/circulars/36711.
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TITLE: GCN CIRCULAR
NUMBER: 36711
SUBJECT: GRB 240619C: AstroSat CZTI detection
DATE: 24/06/20 05:56:11 GMT
FROM: Gaurav Waratkar at IIT Bombay <gauravwaratkar(a)iitb.ac.in>
J. Joshi (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 long-duration GRB 240619C. Inspection of INTEGRAL/SPI-ACS data also showed the detection of the burst.
The source was clearly detected in the CZT detectors in the 20-200 keV energy range. The light curve showed multiple peaks of emission with the strongest peak at 2024-06-19 23:44:51.50 UTC. The measured peak count rate associated with the burst is 186 (+34, -37) counts/s above the background in the combined data of three quadrants (out of four), with a total of 694 (+196, -209) counts. The local mean background count rate was 268 (+3, -4) counts/s. Using cumulative rates, we measure a T90 of 17 (+1, -5) s.
The source was also clearly detected in the CsI anticoincidence (Veto) detector in the 100-500 keV energy range. The light curve showed multiple peaks of emission with the strongest peak at 2024-06-19 23:44:51.11 UTC. The measured peak count rate associated with the burst is 1471 (+90, -96) counts/s above the background in the combined data of all quadrants, with a total of 5520 (+402, -429) counts. The local mean background count rate was 1481 (+7, -8) counts/s. We measure a T90 of 14 (+1, -1) s from the cumulative Veto light curve.
Note that we see an additional peak in INTEGRAL/SPI-ACS data about 70 s after the main episode of this GRB. These peaks are very faint in our data; hence, we do not include them in our T90 calculations.
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.
CZTI GRB detections are reported regularly on the payload site at:
http://astrosat.iucaa.in/czti/?q=grb
View this GCN Circular online at https://gcn.nasa.gov/circulars/36711.
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