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GCN Circular 9336

GRB 090510: Fermi GBM detection
2009-05-10T05:46:27Z (15 years ago)
Sylvain Guiriec at UAH <>
S. Guiriec, V. Connaughton and M. Briggs (UAH)
report on behalf of the Fermi GBM Team:

"At 00:22:59.97 UT on 2009 May 10, the Fermi Gamma-Ray Burst Monitor
triggered and located GRB 090510 (trigger 263607781 / 090510016) which
was also detected by the Swift-BAT (Hoversten et al. 2009, GCN 9331) and
the Fermi-LAT (Ohno et al. 2009, GCN 9334).

The GBM position is consistent with those reported by Swift and the LAT.

The GBM triggered on a precursor lasting 30 ms followed 0.4 s later by an
intense and hard emission period of 0.5 s and a tail lasting
a further 0.5 s.  The intense period has several narrow peaks and
its integrated spectrum is well fit by a Band function with
alpha = -0.80 +/- 0.03, beta = 2.6 +/- 0.3 and EPeak = 4.4 +/- 0.4 MeV.

The peak flux on a 64 ms timescale between 8 keV and 40 MeV was
measured 0.55 s after the trigger to be 80^-2.s^-1.
The 8 keV to 40 MeV fluence in the 0.512 s long period of intense emission
is  (3.0 � 0.2) E-5^-2.

The spectral analysis results presented above are preliminary;
further analysis is on-going."
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