[vsnet-grb-info 9076] GRB 100324B: Suzaku WAM observation of the prompt emission

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  10564
SUBJECT: GRB 100324B: Suzaku WAM observation of the prompt emission
DATE:    10/04/02 03:41:31 GMT
FROM:    Masanori Ohno at ISAS/JAXA  <ohno at astro.isas.jaxa.jp>

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


The bright IPN localized GRB 100324B (GCN 10554 ; Hurley et al.)
triggered the Suzaku Wide-band  All-sky Monitor (WAM) which covers an 
 energy range of 50 keV - 5 MeV at 04:07:36.130 UT (=T0). 
The observed light curve shows a multi-peaked structure starting at T0s, ending 
 at T0+10s, with a duration (T90) of about 9.7 seconds. 
The fluence in 100 - 1000 keV was 3.20 (-0.07, 0.05) x10^-05 erg/cm^2. 
The 1-s peak flux measured from T0+2s was 15.7 +/- 0.3 photons/cm^2/s in the same 
 energy range.

Preliminary result shows that the time-averaged spectrum from 
T0s to T0+10s is well fitted by a GRB Band model as follows.
the low-energy photon index alpha: -0.91 (-0.14, 0.16),
the high-energy photon index beta: -3.05 (-0.53, 0.26),
and the peak energy Epeak: 472 (-25, 27) keV (chi^2/d.o.f = 61.2/50).

All the quoted errors are at statistical 90% confidence level,
in which the systematic uncertainties are not included.

The light curves for this burst are available at:

 http://www.astro.isas.jaxa.jp/suzaku/HXD-WAM/WAM-GRB/grb/trig/grb_table.html