[vsnet-grb-info 7745] GRB 090426B: Fermi GBM detection/observation

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  9299
SUBJECT: GRB 090426B: Fermi GBM detection/observation
DATE:    09/04/29 20:19:46 GMT
FROM:    Michael S. Briggs at UAH and MSFC  <michael.briggs at nasa.gov>

M. S. Briggs (UAH) reports on behalf of the Fermi GBM Team:

"At 01:35:35.23 UT on 26 April 2009, the Fermi Gamma-Ray Burst Monitor
triggered and located GRB 090426B (trigger 262402537 / 090426066).

The on-ground calculated location, using the GBM trigger
data, is RA = 17.6, DEC = -19.2 (J2000 degrees,
equivalent to 01 h 10 m, -19 d 12'), with an uncertainty
of 18.1 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 56 degrees.

The GBM light curve shows a peak followed by a tail with a
T90 duration of 3.8 s (8-1000 keV).   The time-averaged
spectrum from T0-2.048 s to T0+3.072 s is well fit by a
simple power law function with index -1.60 +/- 0.08.

The event fluence (8-1000 keV) in this time interval is
(5.2 +/- 1.2)E-7 erg/cm^2.

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