GRB 230525A
GCN Circular 33877
Subject
GRB 230525A: Fermi GBM Final Localization
Date
2023-05-25T14:54:44Z (2 years ago)
From
Cori Fletcher at USRA <cfletcher@usra.edu>
The Fermi GBM team reports the detection of a likely SHORT GRB
"At 10:46:08 UT on 25 May 2023, the Fermi Gamma-ray Burst Monitor (GBM)
triggered and located GRB 230525A (trigger 706704373/230525449).
The on-ground calculated location, using the Fermi GBM trigger data,
is RA = 45.27, Dec = 69.35 (J2000 degrees, equivalent to J2000 3h 1m, +69d 20'),
with a statistical uncertainty of 6.75 degrees.
The angle from the Fermi LAT boresight is 19 degrees.
The skymap can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2023/bn230525449/quicklook/glg_skymap_all_bn230525449.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/bn230525449/quicklook/glg_healpix_all_bn230525449.fit
The GBM light curve can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2023/bn230525449/quicklook/glg_lc_medres34_bn230525449.gif"
GCN Circular 33879
Subject
GRB 230525A: Fermi GBM Detection
Date
2023-05-25T17:10:06Z (2 years ago)
From
sumanbala2210@gmail.com
S. Bala (USRA), C. Fletcher (USRA), O.J. Roberts (NASA/MSFC) and C. Meegan (UAH)
report on behalf of the Fermi Gamma-ray Burst Monitor Team:
"At 10:46:08.33 UT on 25 May 2023, the Fermi Gamma-ray Burst Monitor (GBM)
triggered and located GRB 230525A (trigger 706704373/230525449).
The Fermi GBM Final Real-time Localization was reported in GCN 33877.
The angle from the Fermi LAT boresight is 19 degrees.
The GBM light curve consists of single peak with a duration (T90)
of 0.12 s (50-300 keV). The time-averaged spectrum
from T0-0.06 to T0+0.06 s is best fit by
a power law function with an exponential high-energy cutoff.
The power law index is -0.80 +/- 0.09 and the cutoff energy,
parameterized as Epeak, is 789 +/- 148 keV.
The event fluence (10-1000 keV) in this time interval is
(8.6 +/- 0.4)E-07 erg/cm^2. The 64-ms peak photon flux measured
starting from T0-0.064 s in the 10-1000 keV band is 25 +/- 1 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 33901
Subject
GRB 230525A: CALET Gamma-Ray Burst Monitor detection
Date
2023-05-31T06:20:08Z (2 years ago)
From
Yuta Kawakubo at Louisiana State University <kawakubo1@lsu.edu>
Y. Kawakubo (LSU), A. Yoshida, T. Sakamoto, S. Sugita (AGU),
K. Yamaoka (Nagoya U), S. Nakahira (RIKEN), Y. Asaoka (ICRR),
S. Torii, 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 short GRB 230525A (Fermi-GBM Final Localization: The
Fermi GBM team, GCN Circ. 33877; Fermi-GBM detection: The Fermi
GBM team, GCN Circ. 33879) was detected in the ground analysis of
the CALET Gamma-ray Burst Monitor (CGBM) data around
10:46:08.33 UTC on 25 May 2023 (referenced to GCN Circ 33879).
The burst signal was seen by all CGBM detectors.
The burst light curve shows a short pulse around the reference time.
We are not able to obtain the duration because no event data is available
for ground-detected events.
The ground-processed light curve is available at
http://cgbm.calet.jp/cgbm_trigger/ground/1369046781/
The CALET data used in this analysis are provided by
the Waseda CALET Operation Center located at Waseda University.