GCN Circular 32845
Subject
GRB 221023A: Fermi GBM Observation
Date
2022-10-25T14:16:07Z (2 years ago)
From
Rachel Dunwoody at UCD <rachel.dunwoody@ucdconnect.ie>
R. Dunwoody (UCD), J. Mangan (UCD) and C. Meegan (UAH), report on behalf of
the Fermi GBM Team:
"At 20:41:34.92 UT on 23 October 2022, the Fermi Gamma-ray Burst Monitor
(GBM) triggered and located GRB 221023A (trigger 688250499 / 221023862),
this localisation was consistent with the Fermi LAT (GCN 32813). This event
was also observed by AGILE (GCN 32825).
The angle from the Fermi LAT boresight is 48 degrees.
The GBM light curve shows one bright peak with a duration (T90) of about 39
s (50-300 keV). The time-averaged spectrum from T0-2 to T0+58 s is best fit
by a Band function with Epeak = 898 +/- 15 keV, alpha = -1.1 +/- 0.004, and
beta = -2.5 +/- 0.03. It is fit equally well with a power law function with
an exponential high-energy cutoff. The power law index is -1.08 +/- 0.003
and the cutoff energy, parameterized as Epeak, is 997 +/- 14 keV.
The event fluence (10-1000 keV) in this time interval is 0.001 +/-
4.350E-06 erg/cm2. The 1-sec peak photon flux measured starting from T0+20
s in the 10-1000 keV band is 60.9 +/- 0.4 ph/s/cm2.
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/"