[vsnet-grb-info 16849] GRB 150811B: Fermi GBM detection

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  18130
SUBJECT: GRB 150811B: Fermi GBM detection
DATE:    15/08/12 02:59:05 GMT
FROM:    Peter Jenke at MSFC  <peter.a.jenke at nasa.gov>

P. Jenke (UAH) reports on behalf of the Fermi GBM Team:

"At 20:22:13.75 UT on August 11 2015, the Fermi Gamma-Ray Burst 
Monitor triggered and located 
GRB 150811B (trigger 461017337/150811849). 
The GBM on-ground location, using the Fermi GBM trigger data, 
is RA = 188.0, Dec = -13.5 (J2000 degrees, equivalent to 
12h 32m 00s, -13d 30'), with an uncertainty of 8.7 
degree (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 
108 degrees.

The GBM light curve consists of a single peak with a duration
(T90) of about 0.6 s (50-300 keV).
The time-averaged spectrum from T0-0.13 s to T0+0.64 s is
adequately fit by a Band function with Epeak = 1300 +/- 100 keV,
Alpha =-0.23 +/- 0.07 and Beta = -3.0 +/- 0.2.

The event fluence (10-1000 keV) in this time interval is
(1.6 +/- 0.1)E-07 erg/cm^2. The 64 ms peak photon flux measured
starting from T0-0.13 s in the 10-1000 keV band
is 8.6 +/- 0.3 ph/s/cm^2.

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