Skip to main content
New Announcement Feature, Code of Conduct, Circular Revisions. See news and announcements

GCN Circular 31778

GRB 220317A: Fermi GBM detection
2022-03-21T16:46:18Z (2 years ago)
Rachel Hamburg at UAH <>
R. Hamburg (UAH) and C. Meegan (UAH)
report on behalf of the Fermi GBM Team:

"At 12:48:30.66 UT on 17 March 2022, the Fermi Gamma-Ray Burst Monitor (GBM)
triggered and located GRB 220317A (trigger 669214115 / 220317534).
which was also detected by the Swift/BAT-GUANO (Tohuvavohu et al. 2022, GCN

The angle from the Fermi LAT boresight at the GBM trigger time is 48

The GBM light curve shows two peaks with a duration (T90)
of about 14 s (50-300 keV). The time-averaged spectrum
from T0-6.1 s to T0+8.2 s is best fit by a power law
function with an exponential high-energy cutoff.
The power law index is -1.1 +/- 0.2 and the cutoff
energy, parameterized as Epeak, is 248 +/- 96 keV.

The event fluence (10-1000 keV) in this time interval is
(1.2 +/- 0.2)E-06 erg/cm^2. The 1-sec peak photon flux measured
starting from T0+4.4 s in the 10-1000 keV band
is 1.6 +/- 0.2 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
Looking for U.S. government information and services? Visit