[vsnet-grb-info 8215] GRB 090802: Fermi GBM detection

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  9742
SUBJECT: GRB 090802: Fermi GBM detection
DATE:    09/08/02 21:19:06 GMT
FROM:    Elisabetta Bissaldi at MPE  <ebs at mpe.mpg.de>

Elisabetta Bissaldi (MPE) reports on behalf of the Fermi GBM Team:


"At 05:39:03.08 UT on 02 August 2009, the Fermi Gamma-Ray Burst Monitor
triggered and located GRB 090802 (trigger 270884345 / 090802235).
The on-ground calculated location, using the GBM trigger
data, is RA = 51.0, DEC = +37.9 (J2000 degrees,
equivalent to 03h 24m, 37d 54'), with an uncertainty
of 4.9 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 123 degrees.

The GBM light curve consists of a single FRED-like pulse
with a duration (T90) of about 128 ms (8-1000 keV).
The time-averaged spectrum from T0-0.016 s to T0+0.056 s is
best fit by a Band function with Epeak = 283 (-53 +58) keV,
alpha = -0.42 (-0.17 +0.21), and beta = -2.4 (-0.7 +0.3)
(Castor C-stat 325 for 361 d.o.f.).

The event fluence (8-1000 keV) in this time interval is
(6.5 +/- 0.3)E-07 erg/cm^2. The 32-ms peak photon flux measured
starting from T0-0.008 s in the 8-1000 keV band
is 61.2 +/- 2.8 ph/s/cm^2.


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