[vsnet-grb-info 12684] GRB 121127A: Suzaku WAM observation of the prompt emission

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  14044
SUBJECT: GRB 121127A: Suzaku WAM observation of the prompt emission
DATE:    12/12/06 08:05:47 GMT
FROM:    Makoto Tashiro at Saitama U/Swift  <tashiro at phy.saitama-u.ac.jp>

Y.Ishida, M. Tashiro, Y. Terada, W. Iwakiri, T. Yasuda,
K. Takahara,　M. Asahina, S. Kobayashi, A. Sakamoto, H. Ueno,
S. Sugimoto (Saitama　U.), M. Akiyama, N. Ohmori, E. Mochinaga,
M. Yamauchi (Univ. of　Miyazaki), K. Yamaoka, M. Kokubun,
T. Takahashi (ISAS/JAXA), Y.　Hanabata, T. Kawano, K. Takaki,
R. Nakamura, Y.Tanaka, M. Ohno, Y.　Fukazawa (Hiroshima U.),
S. Sugita (Nagoya U.), Y. E. Nakagawa (Waseda　U.),
Y. Urata, P. Tsai (NCU), K. Nakazawa, K. Makishima (Univ. of　Tokyo),
on behalf of the Suzaku WAM team, report:

The short, IPN localized GRB 121127A (Golenetskii et al., GCN 14021)
was detected by the the Suzaku Wide-band All-sky Monitor (WAM) which
covers an energy range of 50 keV - 5 MeV at 21:56:01 UT (=T0).

The observed light curve shows a single peak starting at T0-1s, ending
at T0s with a duration (T90) of about 1 seconds.
The fluence in 100 - 1000 keV was 9.34(+0.73/-2.40) x 10^-7 erg/cm^2.
The 1-s peak flux measured from T0-1s was
1.78(+0.16/-0.47) photons/cm^2/s in the same energy range.

Preliminary result shows that the time-averaged spectrum from T0-1s to
T0s is well fitted by a power-law with exponential cutoff model :
   dN/dE ~ E^{-alpha} * exp(-(2-alpha)*E/Epeak) with
   alpha 0.55(+0.57/-0.80), and
   Epeak 759(+273/-166) keV (chi^2/d.o.f. = 32.6/29).
All the quoted errors are at statistical 90% confidence level, in
which the systematic uncertainties are not included.

The light curves with 1-sec time resolution for this burst will be
appeared at:

http://www.astro.isas.jaxa.jp/suzaku/HXD-WAM/WAM-GRB/grb/untrig/grb_table.html