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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."
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