[vsnet-grb-info 11803] GRB 120402B: Fermi GBM detection

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  13194
SUBJECT: GRB 120402B: Fermi GBM detection
DATE:    12/04/03 14:30:16 GMT
FROM:    Andrew Collazzi at NASA/MSFC/ORAU  <andrew.collazzi at nasa.gov>

Andrew C. Collazzi (NASA/ORAU)
reports on behalf of the Fermi GBM Team:

"At 16:04:00.76 UT on 02 April 2012, the Fermi Gamma-ray Burst Monitor (GBM)
triggered and located GRB 120402B (trigger 355075442 / 120402.669).
The on-ground calculated location, using the Fermi GBM trigger data,
is RA = 223.7, Dec = -10.4 (J2000 degrees, equivalent to
J2000 14h 55m, -10° 24'), with a statistical uncertainty of 2.6 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 106 degrees.

The GBM light curve shows a soft, bright, main pulse with some small sustained
emission with a duration (T90) of about 17.5 s (50-300 keV). The time-averaged
spectrum from T0-7.46 to T0+20.192 s is equally well fit by Comptonized Power
Law and a Band function.  

For the CPL function, the best fit parameters are alpha = -1.35 +/- 0.11 and 
Epeak = 37.2 +/- 2.2. The fluence (10-1000 keV) in this time interval
is (3.4 +/- 0.12)E-06 erg/cm^2.

For the Band function, the best fit parameters are alpha = -0.48 +/- 0.37, 
Epeak = 27.5 +/- 2.45, and beta = -2.44 +/- 0.09.  
The fluence (10-1000 keV) in this time interval
is (4.2 +/- 0.22)E-06 erg/cm^2.

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