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GCN Circular 14869

GRB 130609B: Fermi GBM observation
2013-06-11T14:52:13Z (11 years ago)
Veronique Pelassa at UAH <>
V. Pelassa (UAH) reports on behalf of the Fermi GBM Team:

"At 21:38:35.61 UT on 09 June 2013, the Fermi Gamma-Ray Burst Monitor
triggered and located GRB 130609B (trigger 392506718 / 130609902),
which was also detected by the Swift/BAT (H.A. Krimm et al. 2013, GCN 14841).
The GBM on-ground location is consistent with the Swift position.
The angle from the Fermi LAT boresight is 117 degrees.

The GBM light curve consists of two bright peaks within 30s of trigger
and a fainter bump at 170s after trigger with a duration (T90) of about
191 s (50-300 keV).

The time-averaged spectrum from T0+0.003s to T0+28.672s is well fit by
a power law function with an exponential high-energy cutoff.
The power law index is -0.70 +/- 0.02 and the cutoff energy,
parameterized as Epeak, is 536 +/- 18 keV
(Castor statistics 474 for 365 d.o.f.).

The event fluence (10-1000 keV) in this time interval is
(6.02 +/- 0.07)E-05 erg/cm^2. The 1.024-sec peak photon flux measured
starting from T0+6.592 s in the 10-1000 keV band is 13.6 +/-0.4 ph/s/cm^2.

A Band function fits the spectrum equally well (Castor statistics 468
for 364 d.o.f.)
with Epeak= 491 +/- 20 keV, alpha = -0.66 +/- 0.02 and beta = -2.6 +/- 0.2.

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