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GCN Circular 32127

Subject
GRB 220525A: Fermi GBM Detection
Date
2022-05-26T22:19:35Z (2 years ago)
From
Stephen Lesage at Fermi-GBM Team <sjl0014@uah.edu>
S. Lesage (UAH) and C. Meegan (UAH) report on behalf of
the Fermi Gamma-ray Burst Monitor Team:

"At 00:10:54 UT on 25 May 2022, the Fermi Gamma-ray Burst Monitor (GBM)
triggered and located GRB 220525A (trigger 675130259/220525008)
which was also detected by Konus-Wind (D. Frederiks et al. 2022, GCN 32122)
and CALET (Y. Kawakubo et al. 2022, GCN 32125) and localized by IPN
(Kozyrev et al. 2022, GCN 32118).
The Fermi GBM Final Real-time Localization (GCN 32112) is consistent
with the IPN triangulation.

The angle from the Fermi LAT boresight is 58 degrees.

The GBM light curve shows a single bright emission episode with a duration (T90)
of about 16.1 s (10-1000 keV). The time-averaged spectrum
from T0-10 to T0+15 s is best fit by
a power law function with an exponential high-energy cutoff.
The power law index is -1.12 +/- 0.04 and the cutoff energy,
parameterized as Epeak, is 176 +/- 10 keV.

The event fluence (10-1000 keV) in this time interval is
(1.45 +/- 0.04)E-05 erg/cm^2. The 1-sec peak photon flux measured
starting from T0+3.7 s in the 10-1000 keV band is 15.4 +/- 0.3 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/"
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