GRB 090112B

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."

M. Suzuki, M. Ohno, M. Kokubun, T. Takahashi (ISAS/JAXA),
Y. E. Nakagawa, T. Tamagawa (RIKEN), H. Hayashi, E. Sonoda, M. Yamauchi,
H. Tanaka, R. Hara, N. Ohmori, K. Kono (Univ. of Miyazaki), A. Endo,
M. Tashiro, Y. Terada, Y. Urata, K. Onda, N. Kodaka, K. Morigami,
T. Sugasahara, W. Iwakiri (Saitama U.), T. Enoto, K. Nakazawa,
K. Makishima (Univ. of Tokyo), S. Sugita, K. Yamaoka (Aoyama Gakuin U.),
Y. Hanabata, T. Uehara, T. Takahashi, Y. Fukazawa,
C. Kira (Hiroshima U.), S. Hong (Nihon U.), on behalf of
the Suzaku WAM team, report:

The long GRB 090112B (van der Horst et al., GCN 8805
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 ) triggered the
Suzaku Wide-band All-sky Monitor (WAM) which covers an energy
range of 50 keV - 5 MeV at 2009-01-12 17:30:14 UT (=T0).

The observed light curve shows multiple peaks and lasting from
T0-1 s to T0+12 s with a duration (T90) of about 8 seconds. The fluence
in 100 - 1000 keV was (5.2 +/- 0.3) x 10^-6 erg/cm^2. The 1-s peak
flux measured from T0+3 s was 3.5 (+0.2/-0.3) photons/cm^2/s in the
same energy range.

Preliminary result shows that the time-averaged spectrum from T0-1 s
to T0+12 s is well fitted by a single power-law with a photon index
of 2.46 +/- 0.14 (chi^2/d.o.f = 18/22).

All the quoted errors are at statistical 90% confidence level,
in which the systematic uncertainties are not included.

The light curves for this burst are available at:
http://www.astro.isas.jaxa.jp/suzaku/HXD-WAM/WAM-GRB/grb/trig/grb_table.html