[vsnet-grb-info 13020] GRB 130327B: Suzaku WAM observation of the prompt emission

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  14357
SUBJECT: GRB 130327B: Suzaku WAM observation of the prompt emission
DATE:    13/04/01 12:17:36 GMT
FROM:    Makoto Tashiro at Saitama U/Swift  <tashiro at phy.saitama-u.ac.jp>

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

The long GRB 130327B (Chaplin et al GCN14346) was detected by the the
Suzaku Wide-band All-sky Monitor (WAM) which covers an energy range of
50 keV - 5 MeV at 08:24:04.751 UT (=T0).

The observed light curve shows double-peaked structure starting at
T0-1s, ending at T0+33s with a duration (T90) of about 30 seconds.
The fluence in 100 - 1000 keV was 3.29(+0.15/-0.21)x10^-5 erg/cm^2.
The 1-s peak flux measured from T0+23s was 2.23 photons/cm^2/s in the
same energy range.

Preliminary result shows that the time-averaged spectrum from T0-1s to
T0+33s is well fitted by a power-law with exponential cutoff model :
   dN/dE ~  E^{-alpha} * exp(-(2-alpha)*E/Epeak) with
   alpha       0.89(+0.46/-0.56), and
   Epeak       484(+64/-50) keV (chi^2 / d.o.f. = 11.1/13).
All the quoted errors are at statistical 90% confidence level, in which
the systematic uncertainties are included.

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