[vsnet-grb-info 7231] GRB 090112B: Fermi GBM Detection

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  8805
SUBJECT: GRB 090112B: Fermi GBM Detection
DATE:    09/01/13 22:21:26 GMT
FROM:    Alexander van der Horst at NASA/MSFC  <Alexander.J.VanDerHorst at nasa.gov>

A.J. van der Horst (NASA/MSFC/ORAU) reports on behalf of the
Fermi GBM Team:

"At 17:30:15.45 UT on 12 January 2009, the Fermi Gamma-ray Burst Monitor
(GBM) triggered and located GRB 090112B (trigger 253474217 / 090112.729).
The on-ground calculated location, using the Fermi GBM trigger data,
is RA = 192.7, Dec = +22.2 (J2000 degrees, equivalent to
J2000 12h51m, +22d12'), with a statistical uncertainty of 2.1 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 95 degrees.

The GBM light curve shows one pulse with some substructure, with a
duration (T90) of about 12 s (50-300 keV). The time-averaged spectrum
from T0 to T0+8.70 s is best fit by a Band function with
Epeak = 139 +/- 9 keV, alpha = -0.75 +/- 0.06 and beta = -2.43 +/- 0.14.
The fluence (8-1000 keV) in this time interval is (5.4 +/- 0.3)E-6 
erg/cm^2.
The 1-sec peak photon flux measured starting from T0+2.6s in the 8-1000 keV
band is 14 +/- 1 ph/s/cm^2.

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