[vsnet-grb-info 15470] GRB 140829A: Fermi GBM Detection

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  16759
SUBJECT: GRB 140829A: Fermi GBM Detection
DATE:    14/08/31 20:50:38 GMT
FROM:    Matthew Stanbro at UAH/Fermi  <mcs0001 at uah.edu>

M. Stanbro (UAH) reports on behalf of the Fermi GBM Team:

"At 21:07:27.47 UT on 29 August 2014, the Fermi Gamma-Ray Burst Monitor
triggered and located GRB 140829A (trigger 431039250 / 140829880).
The GBM error circle was also observed with iPTF in search of an optical
counterpart of the GRB; no credible counterpart was found (Singer et. al.,
2014, GCN 16758).

The GBM light curve consists of a double pulse with a duration (T90)
of about 19 s (50-300 keV). The time-averaged spectrum from T0-3.1 s
to T0+18.4 s is well fit by a power law function with an exponential
high-energy cutoff.  The power law index is -0.5 +/- 0.2 and
the cutoff energy, parameterized as Epeak, is 324 +/- 43 keV.

The event fluence (10-1000 keV) in this time interval is
(5.12 +/- 0.41)E-06 erg/cm^2. The 1-sec peak photon flux measured
starting from T0+11.52 s in the 10-1000 keV band
is 2.9 +/- 0.4 ph/s/cm^2.

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