TITLE:   GCN CIRCULAR
NUMBER:  15396
SUBJECT: GRB 131028A: Fermi GBM detection
DATE:    13/10/29 13:35:30 GMT
FROM:    Andreas von Kienlin at MPE  <azk@mpe.mpg.de>

A. von Kienlin (MPE) reports on behalf of the Fermi GBM Team:

"At 01:49:02.35 UT on 28 October 2013, the Fermi Gamma-Ray Burst Monitor
triggered and located GRB 131028A (trigger 404617745 / 131028076).

The on-ground calculated location, using the GBM trigger
data, is RA = 57.0, DEC = +72.2 (J2000 degrees,
equivalent to 03 h 48 m, 72 d 12 '), with an uncertainty
of 1.2 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 123 degrees.

This burst was also independently detected by INTEGRAL SPI-ACS.

The GBM light curve consists of a single pulse
with a duration (T90) of about 17 s (50-300 keV).
The time-averaged spectrum from T0-1.28 s to T0+22.27 s is
best fit by a Band function with Epeak = 888 +/-18 keV,
alpha = -0.71 +/- 0.01, and beta = -3.4 +/-0.2. 

The event fluence (10-1000 keV) in this time interval is
(1.62 +/- 0.02)E-04 erg/cm^2. The 1.024-sec peak photon flux measured
starting from T0+8.13 s in the 10-1000 keV band is 62 +/- 1 ph/s/cm^2.

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