[vsnet-grb-info 9843] GRB 100924A: Fermi GBM observation

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  11311
SUBJECT: GRB 100924A: Fermi GBM observation
DATE:    10/09/28 07:11:07 GMT
FROM:    David Gruber at MPE  <dgruber at mpe.mpg.de>

David Gruber (MPE) reports on behalf of the Fermi GBM Team: 

"At 03:58:08.32 UT on 24 September 2010, the Fermi Gamma-Ray Burst Monitor
triggered and located GRB 100924A (trigger 306993490 / 100924165).
which was also detected by the Swift-BAT (Mangano et al. 2010, GCN 11294).
The GBM on-ground location is consistent with the Swift position.
 
The angle from the Fermi LAT boresight is 57 degrees.

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

The GBM light curve shows a bright initial peak
with a duration (T90) of about 9.0 +/- 0.4 s (50-300 keV). 
Fermi entered the SAA ~ 35 s after the trigger.
Thus, the observation of additional emission episodes,
as reported in Mangano et al. 2010, GCN 11294, was not possible.

The time-averaged spectrum from T0+0.003 s to T0+9.088 s is 
best fit by a simple power law function with index -1.59 +0.02/-0.02
(Castor C-STAT 1767 for 725 d.o.f.).

The event fluence (10-1000 keV) in this time interval is 
(3.33 +/- 0.04)E-06 erg/cm^2. The 1-sec peak photon flux measured 
starting from T0+0.384 s in the 10-1000 keV band 
is 7.3 +/- 0.2 ph/s/cm^2.