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GCN Circular 14044

Subject

GRB 121127A: Suzaku WAM observation of the prompt emission

Date

2012-12-06T08:05:47Z (12 years ago)

From

Makoto Tashiro at Saitama U/Swift <tashiro@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 14021Loading...
 
 )
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