[vsnet-grb-info 9311] GRB100522A: Suzaku WAM observation of the prompt emission

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  10795
SUBJECT: GRB100522A: Suzaku WAM observation of the prompt emission
DATE:    10/05/25 03:31:22 GMT
FROM:    Arata Daikyuji at Miyazaki U  <daikyu524 at astro.miyazaki-u.ac.jp>

A. Daikyuji, N. Ohmori, Y. Nishioka, M. Yamauchi (Univ. of Miyazaki),
K. Yamaoka (Aoyama Gakuin U.), S. Sugita (Nagoya U.),
Y. Hanabata, T. Uehara, T. Takahashi, Y. Fukazawa (Hiroshima 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. 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 GRB100522A (Swift/BAT trigger #422783 ; Troja et al., GCN 10784)
was detected by the the Suzaku Wide-band All-sky Monitor (WAM) which
covers an energy range of 50 keV - 5 MeV at 2010-05-22 03:45:52 UT (=T0).

The observed light curve shows a single peak starting at T0, ending
at T0+4s with a duration (T90) of about 3 seconds.
The WAM detected only the first bright peak observed by
Swift/BAT (Barthelmy et al., GCN 10788) and Fermi/GBM(McBreen et al.,
GCN 10790).
The fluence in 100 - 1000 keV was 1.39 (-0.18, +0.15) x10-6 erg/cm2.
The 1-s peak flux measured from T0+1s was 1.50 (-0.27, +0.24)
photons/cm2/s in the same energy range.

Preliminary result shows that the time-averaged spectrum from T0 to
T0+4s is well fitted by a single power-law with a photon index
of 2.26 (-0.18, +0.21) (chi2/d.o.f = 26.8/35).

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