[vsnet-grb-info 6908] GRB 081024C: Fermi Gamma-ray Burst Monitor detection

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  8498
SUBJECT: GRB 081024C:  Fermi Gamma-ray Burst Monitor detection
DATE:    08/11/07 20:34:54 GMT
FROM:    Valerie Connaughton at MSFC  <valerie at nasa.gov>

Valerie Connaughton (UAH) reports on behalf of the Fermi GBM Team:

"At 20:25:34 UT on 24 October 2008, the Fermi Gamma-Ray Burst Monitor
triggered and located GRB 081024C (trigger 246572735 / 081024851).


The on-ground calculated location, using the GBM trigger
data, is RA = 147.6, DEC = -8.2 (J2000 degrees, equivalent to 09h50m,
 -08d12'), with an uncertainty of 3.2 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 78 degrees.

The GBM light curve consists of a single weak peak with some
substructure, lasting about 65 seconds.
The time-averaged spectrum from T0-8 s to T0+57 s is best fit by
a Band function with Epeak = 65 +/- 7 keV,
alpha = -0.6 +/- 0.2, and beta = -2.5 +/- 0.2
(chi squared 358 for 355 d.o.f.)

The event fluence (50 -- 300 keV) in this time interval is
(4.0 +/- 0.9)E-6 erg/cm^2, and its 1-second peak flux in the same
energy range is approximately 1 ph/cm^2/sec.

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