GRB 230524A
GCN Circular 33864
Subject
GRB 230524A: Fermi GBM Final Real-time Localization
Date
2023-05-24T06:16:55Z (2 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 06:06:35 UT on 24 May 2023, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 230524A (trigger 706601200.806822 / 230524255).
The on-ground calculated location, using the Fermi GBM trigger data, is RA = 177.5, Dec = 16.3 (J2000 degrees, equivalent to J2000 11h 50m, 16d 18'), with a statistical uncertainty of 3.2 degrees.
The angle from the Fermi LAT boresight is 93.0 degrees.
The skymap can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2023/bn230524255/quicklook/glg_skymap_all_bn230524255.png
The HEALPix FITS file, including the estimated localization systematic, can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2023/bn230524255/quicklook/glg_healpix_all_bn230524255.fit
The GBM light curve can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2023/bn230524255/quicklook/glg_lc_medres34_bn230524255.gif
GCN Circular 33867
Subject
GRB 230524A: AGILE detection
Date
2023-05-24T11:35:12Z (2 years ago)
From
Gabriele Panebianco <gabriele.panebianco@inaf.it>
G. Panebianco (Univ. Bologna - INAF/OAS Bologna), A. Ursi (ASI and INAF/IAPS), F. Verrecchia, C. Pittori (SSDC, and INAF/OAR), F. Longo (Univ. Trieste and INFN Trieste), M. Tavani (INAF/IAPS, and Univ. Roma Tor Vergata), C. Casentini, A. Argan, M. Cardillo, Y. Evangelista, L. Foffano, G. Piano (INAF/IAPS), A. Addis, L. Baroncelli, A. Bulgarelli, A. Di Piano, V. Fioretti, N. Parmiggiani (INAF/OAS-Bologna), F. Lucarelli (SSDC, and INAF/OAR), M. Marisaldi (INAF/OAS-Bologna, and Bergen University), M. Pilia, A. Trois (INAF/OA-Cagliari), I. Donnarumma, E. Menegoni (ASI), A. Giuliani (INAF/IASF-Mi), and P. Tempesta (TeleSpazio), report on behalf of the AGILE Team:
The AGILE satellite detected the GRB 230524A at T0 = 2023-05-24 06:06:35 s
(UTC), reported by Fermi GBM (GCN #33864).
The burst is clearly visible in the AGILE scientific ratemeters of the
MiniCALorimeter (MCAL; 0.4-100 MeV), and AntiCoincidence (AC; 50-200 keV)
detectors.
The event lasted about 12 s and it released a total number
of 8723 counts in the MCAL detector (above a background rate of 595 Hz)
and 43686 counts in the AC-Top detector (above a background rate of 3171 Hz).
The AGILE ratemeters light curves can be found at http://www.agilescienceapp.it/notices/GRB230524A_AGILE_RM_D.png .
Additional analysis of AGILE data is in progress. Automatic MCAL GRB alert Notices can be found at: https://gcn.gsfc.nasa.gov/agile_mcal.html
GCN Circular 33868
Subject
GRB 230524A: AstroSat CZTI detection
Date
2023-05-24T13:31:35Z (2 years ago)
From
Gaurav Waratkar at IIT Bombay <gauravwaratkar@iitb.ac.in>
P K. Navaneeth (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 GRB 230524A which was also detected by Fermi (Fermi GBM Team, GCN Circ. 33864), and AGILE (Panebianco et al., GCN Circ. 33867).
The source was detected in the 20-200 keV energy range. The light curve peaks at 2023-05-24 06:06:40.50 UTC. The measured peak count rate associated with the burst is 97 (+37, -13) counts/s above the background in the combined data of three quadrants (out of four), with a total of 617 (+249, -270) counts. The local mean background count rate was 324 (+2, -2) counts/s. Using cumulative rates, we measure a T90 of 16 (+6, -10) s.
The source was clearly detected in the CsI anticoincidence (Veto) detector in the 100-500 keV energy range. The light curve peaks at 2023-05-24 06:06:40.50 UTC. The measured peak count rate associated with the burst is 448 (+71, -56) counts/s above the background in the combined data of all quadrants, with a total of 5102 (+531, -606) counts. The local mean background count rate was 1398 (+5, -5) counts/s. We measure a T90 of 22 (+10, -4) s from the cumulative Veto light curve.
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
GCN Circular 33874
Subject
GRB 230524A: Fermi GBM Observation
Date
2023-05-25T10:00:14Z (2 years ago)
From
Andreas von Kienlin at MPE <azk@mpe.mpg.de>
A. von Kienlin (MPE) and C. Meegan (UAH) report on behalf of
the Fermi Gamma-ray Burst Monitor Team:
"At 06:06:35 UT on 24 May 2023, the Fermi Gamma-ray Burst Monitor (GBM)
triggered and located GRB 230524A (trigger 706601200/230524255),
which was also detected by AGILE (Panebianco et al. 2023, GCN 33867)
and AstroSAT/CZTI (Navaneeth et al. 2022, GCN 33868).
The Fermi GBM Final Real-time Localization was reported in GCN 33864.
The GBM light curve consists of a single emission with a duration (T90)
of about 35 s (50-300 keV). The time-averaged spectrum
from T0-2.0 to T0+36.9 s is best fit by
a power law function with an exponential high-energy cutoff.
The power law index is -0.99 +/- 0.04 and the cutoff energy,
parameterized as Epeak, is 1632 +/- 415 keV.
The event fluence (10-1000 keV) in this time interval is
(1.58 +/- 0.05)E-05 erg/cm^2. The 1-sec peak photon flux measured
starting from T0-2 s in the 10-1000 keV band is 2.7 +/- 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/"