[vsnet-grb-info 14120] GRB 131031A: Fermi GBM detection

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  15434
SUBJECT: GRB 131031A: Fermi GBM detection
DATE:    13/11/01 16:11:16 GMT
FROM:    Narayana Bhat at U Alabama/Huntsville/GBM  <Narayana.Bhat at nasa.gov>

G. Fitzpatrick (UCD) and P. N. Bhat (UAH) report on behalf of the Fermi GBM Team:

At 11:33:32.82 UT on 31 October 2013, the Fermi Gamma-Ray Burst Monitor
triggered and located GRB 131031A (trigger 404912015/131031482). This
GRB was also detected by Swift in ground analysis (Cummings, GCN 15421)
and by Konus-Wind (Golenetskii et al., GCN 15428). The angle from
the Fermi LAT boresight is 46 degrees.

The on-ground calculated location is consistent with the Swift location.
The GBM light curve is multi-peaked with a duration (T90) of about 7.4 s
(50-300 keV). The time-averaged spectrum from T0+0.003 s to T0+7.424 s is
adequately fit by a Band function with Epeak = 92.1 +/- 7.0 keV,
alpha = -0.8 +/- 0.1  , and beta = -2.3 +/- 0.1.

The event fluence (10-1000 keV) in this time interval is
(4.3 +/- 0.1)E-06 erg/cm^2. The 1-sec peak photon flux measured
starting from T0+0.6 s in the 10-1000 keV band is 10.2 +/- 0.3 ph/s/cm^2.

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