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GCN Circular 16971

Subject
GRB 141028A: Fermi GBM detection
Date
2014-10-28T19:00:19Z (9 years ago)
From
Oliver Roberts at UCD/Fermi <oliver.roberts@ucd.ie>
O.J. Roberts (UCD) reports on behalf of the Fermi GBM Team:

"At 10:54:46.78 UT on 28 October 2014, the Fermi Gamma-Ray
Burst Monitor triggered and located GRB 141028A
(trigger 436186489 / 141028455), which was also detected by
the LAT (Bissaldi et al. 2014, GCN 16969). The GBM on-ground
location, using the Fermi GBM trigger data, is consistent with
the LAT location.

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 = 316.32, DEC = +1.67, 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 angle from the Fermi LAT boresight is about 19 degrees.

The GBM light curve consists of a single episode with a duration
(T90) of about 31.5 s (50-300 keV). The time-averaged spectrum
from T0+0s to T0+31.7s is well fit by a Band function with
Epeak = 249.9 (+/-12.6) keV, alpha = -0.71 +/- 0.03 , and
beta = -1.93 (+/-0.03).

The event fluence (10-1000 keV) in this time interval is
(3.478 +/- 0.009)E-05 erg/cm^2. The 1-sec peak photon flux
measured starting from T0+12.6 s in the 10-1000 keV band
is 17.3 +/- 0.3 ph/s/cm^2.

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