GCN Circular 32389
Subject
GRB 220711C: Fermi GBM Observation
Date
2022-07-13T21:56:21Z (3 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 16:11:58.54 UT on 11 July 2022, the Fermi Gamma-ray Burst Monitor (GBM)
triggered and located GRB 220711C (trigger 679248723/220711675)
which was also detected by Konus-Wind (A. Ridnaia, et al. 2022, GCN 32382),
Swift/BAT-GUANO (G. Raman et al. 2022, GCN 32384),
and localized by IPN (D. Svinkin et al. 2022, GCN 32373).
The on-ground calculated location, using the GBM trigger data,
is RA = 81.06, DEC = -48.16 (J2000 degrees, equivalent
to 05h 24m, -48d 10'), with an uncertainty of 3.5 degrees
(radius, 1-sigma containment, statistical only; there is additionally a
systematic error which we have characterized as a core-plus-tail model,
with 90% of GRBs having a 3.7 deg error and a small tail suffering a
larger than 10 deg systematic error. [Connaughton et al. 2015, ApJS, 216, 32] ).
The Fermi GBM on-ground location is consistent with the IPN triangulation.
The angle from the Fermi LAT boresight is 130 degrees.
The GBM light curve consists of a single emission episode with a duration (T90)
of about 0.3 s (10-1000 keV). The time-averaged spectrum
from T0-0.06 to T0+0.26 s is best fit by
a power law function with an exponential high-energy cutoff.
The power law index is -0.1 +/- 0.2 and the cutoff energy,
parameterized as Epeak, is 972.6 +/- 136.0 keV.
The event fluence (10-1000 keV) in this time interval is
(1.51 +/- 0.08)E-06 erg/cm^2. The 64-ms peak photon flux measured
starting from T0+0 s in the 10-1000 keV band is 13.6 +/- 1.4 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/"