GCN Circular 18126

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

"At 11:38:08.91 on August 10th 2015, the Fermi Gamma-Ray
Burst Monitor triggered and located GRB 150810A (trigger
460899492/150810485). The GBM on-ground location, using
the Fermi GBM trigger data, is RA = 283.20, Dec = +21.18
with an uncertainty of 3 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 of the burst direction to the Fermi LAT boresight is
62 degrees.

The GBM light curve consists of two unresolved peaks with a
duration of about 0.5s (50-300 keV). The time-averaged
spectrum from T0-0.064s to T0+0.448s is best fit by a power
law with an exponential high-energy cutoff. The power law index
is -0.68 +/- 0.05 and the cutoff energy, parameterized as
Epeak, is 1294 +/-159 keV.

The event fluence (10-1000 keV) in this time interval is
(1.87 +/- 0.04)E-06 erg/cm^2. The 64 ms peak photon flux
measured starting from T0+0s in the 10-1000 keV band is
17.9 +/- 1.1 ph/s/cm^2.

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