GCN Circular 4606

K. Nakazawa (ISAS/JAXA), K. Yamaoka , Y. Nakagawa (AGU),
M. Yamauchi, E. Sonoda, S. Maeno (Univ. of Miyazaki),
T. Murakami, D. Yonetoku (Kanazawa U.),
M. Tashiro, K. Abe, K. Onda (Saitama U.),
N. Ishikawa, A. Yoshida (AGU),
N. Yamasaki, Y. Terashima, H. Murakami (ISAS/JAXA),
K. Torii (Osaka U.), Y. Ichikawa, S. Murasawa,
R. Fujimoto (ISAS/JAXA), Tatsuya Inui (Kyoto U.),
on behalf of Suzaku GRB ToO team report:

We have carried out refined analysis on the data from the Suzaku
TOO observation of GRB060105 (Ziaeepour et al. GCN4429
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 ).
The Suzaku observation started on 2006,
January 5 at 12:10 UT, 5 hours 20 minutes after the GRB,
and ended on January 6, at 12:00 UT.
A good exposure of 35 ks was obtained in total.

As reported by Mitsuda et al (GCN4449
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 ), the afterglow of
GRB060105 is clearly detected in the XIS images and
its position is fully consistent with the refined Swift/XRT one
(Godet et al., GCN4433
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 ).

Suzaku XIS spectra ranging 0.5-8 keV are well described
with an absorbed power law model. The derived best fit photon
index and column density are Gamma = 2.1+/- 0.1 and
NH = (3.0 +/- 0.6) x 10^21 cm^-2, respectively.
No signature of spectral variability is detected during the observation.
The flux fades along the Suzaku observation
from (1.9 +/- 0.3) x 10^-12 erg/s/cm2 (T_burst + 5.7-7.0 hours)
to (1.5 +/- 0.5) x 10^-13 erg/s/cm2 (T_burst + 26-28 hours)
in the 2-10 keV energy band.  Decay index was found to be -1.3 +/- 0.2.
Note that a possible 10% systematic calibration error is not included 
in the errors quoted above.
These results are generally consistent with those obtained by analyzing 
the Swift/XRT data.