[vsnet-grb-info 16397] GRB 150404A: Fermi GBM detection

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  17678
SUBJECT: GRB 150404A: Fermi GBM detection
DATE:    15/04/05 14:00:24 GMT
FROM:    Hoi-Fung Yu at MPE  <sptfung at mpe.mpg.de>

H.-F. Yu (MPE) and M. Stanbro (UAH) report on behalf of the Fermi GBM Team:

"At 17:35:03.72 UT on 04 April 2015, the Fermi Gamma-Ray Burst Monitor
triggered and located GRB 150404A (trigger 449861706 / 150404733), 
which is also detected in optical by MASTER-SAAO (Tyurina et al., GCN 17676).

The on-ground calculated location, using the GBM trigger data, is
RA = 165.9, Dec = -67.4 (J2000 degrees, equivalent to 11h 04m, -67d 24'),
with an uncertainty of 8.9 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 about 84 degrees.

The GBM light curve consists of one single short pulse with a 
duration (T90) of about 4.8 s (50-300 keV). The time-averaged 
spectrum from T0-1.024 s to T0+2.048 s is best fit by a power law 
function with an exponential high-energy cutoff.  The power law 
index is -0.78 +/- 0.25 and the cutoff energy, parameterized as 
Epeak, is 90.9 +/- 14.1 keV.

The event fluence (10-1000 keV) in this time interval is
(5.9 +/- 0.6)E-07 erg/cm^2. The 1.024-sec peak photon flux measured
starting from T0+0.064 s in the 10-1000 keV band
is 3.2 +/- 0.3 ph/s/cm^2.

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