[vsnet-grb-info 9476] GRB 100707A: Suzaku WAM observation of the prompt emission

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  10950
SUBJECT: GRB 100707A: Suzaku WAM observation of the prompt emission
DATE:    10/07/10 07:02:25 GMT
FROM:    Yoshitaka Hanabata at Hiroshima U  <hanabata at hep01.hepl.hiroshima-u.ac.jp>

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

The long GRB 100707A (Fermi/GBM trigger #300156400; C. Wilson-Hodge et al.,
GCN 10944; Fermi-LAT detection; V. Pelassa et al., GCN 10945)
triggered the Suzaku Wide-band All-sky Monitor (WAM) which covers an
energy of 50 keV - 5 MeV at 2010-07-07 00:46:38.91 UT (T=0).

The observed light curve shows a FRED-like peak structure lasting from
T0-0.5s to T0+18.5s with T90 of about 12 seconds. The fluence in 100 -
1000 keV was 5.26 (+/-0.27) x 10^-5 erg/cm^2. The 1-s peak flux
measured from T0+1.5s was 32.24 (-1.28, +1.22) photons/cm^2/s in the
same energy range.

Preliminary result shows that the time-averaged spectrum from T0-0.5s
to T0+18.5s is well fitted by a single power-law with a photon index
of 2.15 (-0.05, +0.06) (chi^2/d.o.f = 39.4/25).

Due to the brightness of this burst, a 3% systematic error was added
for low energy channels.  In addition, there might be some calibration
uncertainties in these spectral parameters because GRB photons came to
the WAM detector by passing through the large Ne dewar of the X-ray
micro-calorimeter (XRS).
All the errors are quoted at 90% confidence level.

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