[vsnet-grb-info 15713] GRB 141031A: Fermi GBM detection

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  17001
SUBJECT: GRB 141031A: Fermi GBM detection
DATE:    14/10/31 16:44:12 GMT
FROM:    Oliver Roberts at UCD/Fermi  <oliver.roberts at ucd.ie>

O.J. Roberts (UCD) reports on behalf of the Fermi GBM Team:

"At 07:18:21.67 UT on the 31st of October 2014, the Fermi
Gamma-Ray Burst Monitor triggered and located GRB 141031A
(trigger 436432704 / 141031304), which was also detected by
Swift (Gompertz et al. 2014, GCN 16995). The GBM on-ground
location, using the Fermi GBM trigger data, is consistent with
the Swift location.

The angle from the Fermi LAT boresight is about 34 degrees.

The GBM light curve consists of a single peak with a duration
(T90) of about 19.4 s (50-300 keV). The time-averaged spectrum
from T0-6.1 s to T0+13.3 s is well fit by a power law function
with an exponential high-energy cutoff.  The power law index is
-1.09 +/- 0.06  and the cutoff energy, parameterized as Epeak,
is 410 +/- 66 keV.

A Band function fits the spectrum equally well with
Epeak = 221 (+/-57) keV, alpha = -0.92 +/- 0.12 , and
beta = -1.76 (+/-0.09).

The event fluence (10-1000 keV) in this time interval is
(5.7 +/- 0.2)E-06  erg/cm^2. The 1-sec peak photon flux
measured starting from T0+3.8 s in the 10-1000 keV band
is 2.7 +/- 0.2 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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