[vsnet-grb-info 9117] GRB 100413A: Suzaku WAM observation of the prompt emission

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  10604
SUBJECT: GRB 100413A: Suzaku WAM observation of the prompt emission
DATE:    10/04/17 06:53:33 GMT
FROM:    Satoshi Sugita at Aoyama Gakuin U.  <sugita at phys.aoyama.ac.jp>

S. Sugita (Nagoya U.), K. Yamaoka (Aoyama  Gakuin U.), M. Ohno,
M. Kokubun, T. Takahashi (ISAS/JAXA), Y. E. Nakagawa, M. Suzuki,
T. Tamagawa (RIKEN), N. Vasquez (Tokyo Tech.), Y. Urata, H.M. Lin,
P. Tsai (NCU), Y. Nishioka, N. Ohmori, A. Daikyuji, E. Sonoda, K. Kono,
K. Noda, M. Yamauchi (Univ. of Miyazaki), T. Sugasahara, M. Tashiro,
Y. Terada, W. Iwakiri (Saitama U.), Y. Hanabata, T. Uehara,
T. Takahashi, Y. Fukazawa (Hiroshima U.), T. Enoto, K. Nakazawa,
K. Makishima (Univ. of Tokyo), S. Hong (Nihon U.),
on behalf of the Suzaku WAM team, report

The very long GRB 100413A (Swift/BAT trigger #419404 ;
Holland et al., GCN 10581)

was detected by the the Suzaku Wide-band  All-sky Monitor (WAM)
which covers an energy range of 50 keV - 5 MeV at 2010-04-13 17:33:28 UT
(=T0).

The observed light curve shows a multi-peaked structure
 lasting to T0+220s with a duration T90 of about 160 seconds.
The fluence in 100 - 1000 keV was 1.59 (-0.83, +0.21) x10^-5 erg/cm^2.
 The 1-s peak flux measured from T0+118s was 0.38 (-0.27, +0.14)
photons/cm^2/s in the same  energy range.

Preliminary result shows that the time-averaged spectrum from
T0-2s to T0+213s is well fitted by a power-law with exponential
cutoff model:
  dN/dE ~  E^{-alpha} * exp(-(2-alpha)*E/Epeak) with
  alpha       -0.59 (-1.64, +1.27), and
  Epeak       364 (-55, +98) keV (chi^2/d.o.f. = 37.9/30).

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