Skip to main content
Testing. You are viewing the public testing version of GCN. For the production version, go to
Introducing Einstein Probe, Astro Flavored Markdown, and Notices Schema v4.0.0. See news and announcements

GCN Circular 10539

GRB 100322A: Fermi GBM detection
2010-03-22T20:25:58Z (14 years ago)
Alexander van der Horst at NASA/MSFC <>
A.J. van der Horst (NASA/MSFC/ORAU) and D. Tierney (UCD)
report on behalf of the Fermi GBM Team:

"At 01:05:09.64 UT on 22 March 2010, the Fermi Gamma-Ray Burst Monitor
triggered and located GRB 100322A (trigger 290912711 / 100322045).
The on-ground calculated location, using the GBM trigger data, is
RA=23.33, Dec=-10.22 (J2000 degrees, equivalent to 23h20m, -10d13'),
with an uncertainty of 1.20 degrees (radius, 1-sigma containment,
statistical only; there is additionally a systematic error
which is currently estimated to be 2 to 3 degrees).
The angle from the Fermi LAT boresight is 96 degrees.

The GBM light curve consists of multiple peaks with a duration
(T90) of 37.0 +/- 0.3 s (50-300 keV).
The time-averaged spectrum from T0-1.0 s to T0+41.0 s is best fit by
a Band function with Epeak = 309 +/- 16 keV, alpha = -0.88 +/- 0.02,
and beta = -2.15 +/- 0.05 (Cstat 1095 for 602 d.o.f.).

The event fluence (10-1000 keV) in this time interval is
(6.13 +/- 0.04)E-5 erg/cm^2. The 1-sec peak photon flux
measured starting from T0+1.1 s in the 10-1000 keV band
is 16.1 +/- 0.3 ph/s/cm^2.

The temporal and spectral analysis results presented above are
preliminary; final results will be published in the GBM GRB Catalog."
Looking for U.S. government information and services? Visit