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GCN Circular 16224

Subject
GRB 140508A: Fermi GBM detection
Date
2014-05-08T14:51:43Z (10 years ago)
From
Hoi-Fung Yu at MPE <sptfung@mpe.mpg.de>
Hoi-Fung Yu (MPE) and Adam Goldstein (ORAU/NASA MSFC)
report on behalf of the Fermi GBM Team:

"At 03:03:54.60 UT on 08 May 2014, the Fermi Gamma-Ray Burst Monitor
triggered and located GRB 140508A (trigger 421211037 / 140508128).
The trigger resulted in an Autonomous Repoint Request (ARR) that was 
accepted and the spacecraft slewed to the GBM in-flight location.

The on-ground calculated location, using the GBM trigger data,
is RA = 250.1, Dec = 44.4 (J2000 degrees, equivalent to 16h 40m, 44d 24'),
with an uncertainty of 1.0 degrees (radius, 1-sigma containment,
statistical only; there is additionally a systematic error which is
currently estimated to be 2 to 3 degrees).

The initial angle from the Fermi LAT boresight is 112 degrees.

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

The GBM light curve consists of several pulses with decaying peak flux
with a duration (T90) of about 44.3 s (50-300 keV). The time-averaged
spectrum from T0-0.512 s to T0+51.712 s is well fit by a Band function
with Epeak = 256.2 +/- 11.8 keV, alpha = -1.07 +/- 0.02, and
beta = -2.38 +/- 0.09.

The event fluence (10-1000 keV) in this time interval is
(6.24 +/- 0.07)E-05 erg/cm^2. The 1.024-sec peak photon flux measured
starting from T0+4.480 s in the 10-1000 keV band is 66.8 +/- 1.0 ph/s/cm^2.

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