[vsnet-grb-info 10859] GRB 110815A : Suzaku WAM observation of the prompt emission

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  12280
SUBJECT: GRB 110815A : Suzaku WAM observation of the prompt emission
DATE:    11/08/19 02:39:31 GMT
FROM:    Norisuke Ohmori at Miyazaki U  <ohmori at astro.miyazaki-u.ac.jp>

N. Ohmori, M. Akiyama, M. Yamauchi (Univ. of Miyazaki),
M. Ohno, Y. Hanabata, T. Uehara, T. Takahashi, M. Mizuno, 
Y. Fukazawa (Hiroshima U.), K. Yamaoka (Aoyama Gakuin U.),
S. Sugita (Nagoya U.), T. Yasuda, Y. Terada, W. Iwakiri, 
K. Takahara, M. Asahina, S. Kobayashi, M. Tashiro (Saitama U.), 
M. Kokubun, T. Takahashi (ISAS/JAXA), Y. E. Nakagawa (Waseda U.), 
Y. Urata, P. Tsai, C-J. Chuang (NCU), K. Nakazawa, 
K. Makishima (Univ. of Tokyo), on behalf of the Suzaku WAM team, report:


The long GRB110815A (localized by IPN; Hurley et al., GCN12277) 
triggered the Suzaku Wide-band All-sky Monitor (WAM)
which covers an energy range of 50 keV - 5 MeV at 09:40:57.524 UT (=T0).

The observed light curve shows two peaks starting at T0 s, ending
at T0+17 s, with a duration (T90) of about 13 seconds. The fluence in
100 - 1000 keV was 2.84 (-0.04, +0.05) x 10^-5 erg/cm^2. The 1-s peak
flux measured from T0+2 s was 19.62 (-0.82, +0.92) photons/cm^2/s in the
same range.

Preliminary result shows that the time-averaged spectrum from
T0 s to T0+17 s is well fitted by a power-law with exponential cutoff model:
 dN/dE ~  E^{-alpha} * exp(-(2-alpha)*E/Epeak) with
 alpha       1.45 (-0.13, +0.13), and
 Epeak       300 (-25, +20) keV (chi^2/d.o.f. = 102.1/88).

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