[vsnet-grb-info 8183] GRB 090711: Fermi GBM detection

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  9713
SUBJECT: GRB 090711: Fermi GBM detection
DATE:    09/07/27 14:10:00 GMT
FROM:    Bill Paciesas at UAH  <bill.paciesas at nasa.gov>

Colleen A. Wilson-Hodge (NASA/MSFC)
reports on behalf of the Fermi GBM Team:

"At 20:23:22.92 UT on 11 July 2009, the Fermi Gamma-Ray Burst Monitor
triggered and located GRB 090711 (trigger 269036604 / 090711850).

The on-ground calculated location, using the GBM trigger
data, is RA = 139.6, DEC = -64.7 (J2000 degrees,
equivalent to 09 h 18 m, -64 d 42 '), with an uncertainty
of 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 13 degrees.

The GBM light curve consists of multiple peaks
with a duration of at least 100 s (8-1000 keV). The GBM detectors
were turned off for SAA entry about 83 seconds after the
trigger. The time-averaged spectrum from T0-20.992 s to T0+82.433 s is
adequately fit by a power law function with an exponential
high energy cutoff.  The power law index is 1.3 +/- 0.1 and
the cutoff energy, parameterized as Epeak, is 210 +/- 70  keV

The event fluence (8-1000 keV) in this time interval is
(1.17 +/- 0.16 )E-05 erg/cm^2. The 1-sec peak photon flux measured
starting from T0+1.536 s in the 8-1000 keV band
is 4.2 +/- 0.6 ph/s/cm^2.

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