[vsnet-grb-info 9058] GRB 100325A: Fermi GBM detection

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  10546
SUBJECT: GRB 100325A: Fermi GBM detection
DATE:    10/03/26 14:26:50 GMT
FROM:    Andreas von Kienlin at MPE  <azk at mpe.mpg.de>

A. von Kienlin (MPE) reports on behalf of the Fermi GBM Team: 

"At 06:36:08.02 UT on 25 March 2010, the Fermi Gamma-Ray Burst Monitor
triggered and located GRB 100325A (trigger 291191770/100325275).

The on-ground calculated location, using the GBM trigger 
data, is RA = 332.3, DEC = -28.6 (J2000 degrees, 
equivalent to 22h 09m, -28d 36'), 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 9 degrees.

The GBM light curve consists of a single structured pulse with a 
duration (T90) of 8.3 +/- 1.9 s (8-1000 keV).

The time-averaged spectrum from T0-1.664 s to T0+7.552 s is 
best fit by a power law function with an exponential
high energy cutoff. The power law index is -0.45(+0.12/-0.11) and
the cutoff energy, parameterized as Epeak, is 159.3 (+12.7/-10.8) keV
(CSTAT 502 for 482 d.o.f).

The event fluence (8-1000 keV) in this time interval is 
(1.99 +/- 0.04)E-06 erg/cm^2. The 1.024-sec peak photon flux measured 
starting from T0+0.512 s in the 8-1000 keV band 
is 5.0 +/- 0.2 ph/s/cm^2.

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