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GCN Circular 13785

Subject
GRB 120919A: Fermi GBM detection
Date
2012-09-20T11:02:08Z (11 years ago)
From
Arne Rau at MPE <arau@mpe.mpg.de>
Arne Rau (MPE) reports on behalf of the Fermi GBM Team:

"At 07:24:41.98  UT on 19 September 2012, the Fermi Gamma-Ray Burst Monitor
triggered and located GRB 120919A (trigger 369732284 / 120919309).

The on-ground calculated location, using the GBM trigger
data, is RA = 213.4, DEC = -46.3 (J2000 degrees,
equivalent to 14 h 14 m, -46 d 18 '), with an uncertainty
of 1.1 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 63 degrees.
Moreover, this burst was bright enough to result in a Fermi spacecraft
autonomous re-point request (ARR) maneuver.

This burst was also independently detected by INTEGRAL SPI-ACS.

The GBM light curve shows a single bright pulse
with a duration (T90) of about 22.5 s (50-300 keV).
The time-averaged spectrum from T0+0.003 s to T0+10.496 s is
best fit by a Band function with Epeak = 162 +/- 8 keV,
alpha = -0.76 +/- 0.04, and beta = -2.15 +/- 0.06

The event fluence (10-1000 keV) in this time interval is
(1.679 +/- 0.026)E-05 erg/cm^2. The 1.024-sec peak photon flux measured
starting from T0+2.62 s in the 10-1000 keV band
is 25.3 +/- 0.3 ph/s/cm^2.

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

[GCN OPS NOTE(20sep12):  Per author's request, the fluence value
was changed from "(1.60 +/- 0.03)E-06" to "(1.679 +/- 0.026)E-05".]
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