Skip to main content
Testing. You are viewing the public testing version of GCN. For the production version, go to
New Announcement Feature, Code of Conduct, Circular Revisions. See news and announcements

GCN Circular 31506

GRB 220118A: Fermi GBM detection
2022-01-20T16:39:29Z (2 years ago)
Boyan A. Hristov at UAH <>
Cori Fletcher (USRA) and C. Meegan (UAH) and Boyan A. Hristov
(UAH) report on behalf of the Fermi GBM Team:

"At 18:20:35.84 UT on 18 January 2022, the Fermi Gamma-Ray
Burst Monitor (GBM) triggered and located GRB 220118A
(trigger 664222840 / 220118764), which was also detected by
the Swift BAT/XRT (N. J. Klingler et al. 2022, GCN 31490) and
observed by SWIFT UVOT (A. Belles et al. 2022, GCN 31498).
The Fermi GBM Final Real-time Localization (GCN 31489) is
consistent with the Swift position.

The GBM light curve shows a single peak with a duration (T90)
of about 19 s (50-300 keV).  The time-averaged spectrum from
T0+0.003 s to T0+18.176 s is best fit by a power law function
with an exponential high-energy cutoff.  The power law index is
-1.08 +/- 0.09 and the cutoff energy, parameterized as Epeak,
is 148.30 +/- 17.50 keV.

The event fluence (10-1000 keV) in this time interval is
(3.017 +/- 0.182)E-06.  The 1-sec peak photon flux measured
starting from T0+3.39204 s in the 10-1000 keV band is
4.0 +/- 0.28 ph/s/cm^2.

The spectral analysis results presented above are preliminary;
final results will be published in the GBM GRB Catalog:

For Fermi GBM data and info, please visit the official Fermi
GBM Support Page:"
Looking for U.S. government information and services? Visit