[vsnet-grb-info 7930] GRB 090529B: Fermi GBM detection

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  9473
SUBJECT: GRB 090529B: Fermi GBM detection
DATE:    09/06/01 15:04:50 GMT
FROM:    Arne Rau at MPE  <arau at mpe.mpg.de>

Arne Rau (MPE) reports on behalf of the Fermi GBM Team:

"At 07:26:22.41 UT on 29 May 2009, the Fermi Gamma-Ray Burst Monitor
triggered and located GRB 090529B (trigger 265274784 / 090529310).

The on-ground calculated location, using the GBM trigger
data, is RA = 231.2, DEC = +32.2 (J2000 degrees,
equivalent to 15 h 25 m, 32 d 12 '), with an uncertainty
of 7.2 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 36 degrees.

The GBM light curve consists of a single peak
with a duration (T90) of about 5.1 s (8-1000 keV).
The time-averaged spectrum from T0-1.792 s to T0+5.376 s is
best fit by a Band function with Epeak = 142 +/- 56 keV,
alpha = -0.7 +/- 0.3, and beta = -2.0 +/- 0.3

(chi squared 561 for 544 d.o.f.).

The event fluence (8-1000 keV) in this time interval is
(3.4 +/- 0.9)E-07 erg/cm^2. The 1.28-sec peak photon flux measured
starting from T0+0.003 s in the 8-1000 keV band
is 4.1 +/- 0.1 ph/s/cm^2.

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