[vsnet-grb-info 7969] GRB 090612: Fermi GBM detection

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  9510
SUBJECT: GRB 090612: Fermi GBM detection
DATE:    09/06/15 15:15:49 GMT
FROM:    Narayana Bhat at U Alabama/Huntsville/GBM  <Narayana.Bhat at nasa.gov>

C. A. Meegan (USRA) and P. N. Bhat (UAH)
report on behalf of the Fermi GBM Team:

"At 14:50:50.49 UT on 12 June 2009, the Fermi Gamma-Ray Burst Monitor
triggered and located GRB 090612 (trigger 266511052 / 090612619 ).

The on-ground calculated location, using the GBM trigger
data, is RA = 81.1, DEC = 17.8 (J2000 degrees,
equivalent to 05h 24.3 m, 17 d 45'), with an uncertainty
of 2.2 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 56 degrees.

The GBM light curve shows of single strong pulse preceded by
weaker pre-trigger emission with a duration (T90) of about 58 s (8-1000
keV). 
The time-averaged spectrum from T0-1.024 s to T0+5.12 s is
adequately fit by a Band function with Epeak = 357 +/- 59 keV,
alpha = -0.6 +/- 0.1, and beta = -1.9 +/- 0.1

(chi squared 679.7 for 604 d.o.f.).

The event fluence (8-1000 keV) in this time interval is
(2.37 +/- 0.14)E-06 erg/cm^2. The 1-sec peak photon flux measured
starting from T0 s in the 8-1000 keV band
is 1.63 +/- 0.1 ph/s/cm^2.

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