[vsnet-grb-info 7931] GRB 090529C: Fermi GBM detection

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  9474
SUBJECT: GRB 090529C: Fermi GBM detection
DATE:    09/06/01 15:09:17 GMT
FROM:    Arne Rau at MPE  <arau at mpe.mpg.de>

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

"At 13:32:00.49  UT on 29 May 2009, the Fermi Gamma-Ray Burst Monitor
triggered and located GRB 090529C (trigger 265296722 / 090529564).

The on-ground calculated location, using the GBM trigger
data, is RA = 162.7, DEC = 47.3 (J2000 degrees,
equivalent to 10 h 51 m, 47 d 18 '), with an uncertainty
of 1.5 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 69 degrees.

This burst was also independently detected by INTEGRAL SPI-ACS.

The GBM light curve consists of two narrow pulses
with a duration (T90) of about 10.4 s (8-1000 keV).
The time-averaged spectrum from T0-0.002 s to T0+10.048 s is
best fit by a Band function with Epeak = 188 +/- 15 keV,
alpha = -0.84 +/- 0.05, and beta = -2.1 +/- 0.1

(chi squared 795 for 648 d.o.f.).

The event fluence (8-1000 keV) in this time interval is
(3.1 +/- 0.1)E-06 erg/cm^2. The 1.028-sec peak photon flux measured
starting from T0+9.024 s in the 8-1000 keV band
is 25 +/- 1 ph/s/cm^2.

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

We further report that the Fermi Observatory executed a maneuver 
following this trigger and tracked the
burst location for the next 5 hours, subject to Earth-angle constraints. "