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GCN Circular 10023

GRB 091010: Suzaku WAM observation of the prompt emission
2009-10-15T09:56:22Z (15 years ago)
Masanori Ohno at ISAS/JAXA <>
N. Vasquez (Tokyo Tech.), M. Ohno, M. Suzuki,M. Kokubun,
T. Takahashi (ISAS/JAXA), K. Yamaoka (Aoyama Gakuin U.),
N. Ohmori, E. Sonoda, K. Kono, H. Hayashi, A. Daikyuji,
Y. Nishioka, K. Noda, M. Yamauchi (Univ. of Miyazaki),
Y. Hanabata, T. Uehara, T. Takahashi, Y. Fukazawa (Hiroshima U.),
W. Iwakiri, M. Tashiro, Y. Terada, A. Endo, K. Onda, T. Sugasahara  
(Saitama U.),
Y. Urata (NCU), T. Enoto, K. Nakazawa, K. Makishima (Univ. of Tokyo),
Y. E. Nakagawa, T. Tamagawa (RIKEN), S. Hong (Nihon U.),
S. Sugita (Nagoya U.)on behalf of the Suzaku WAM team, report:

The long GRB 091010 (Fermi trigger #276835391/091010113,
von Kienlin et al., GCN10018, SuperAGILE Donnarumma et al., GCN 10004)
triggered the Suzaku Wide-band  All-sky Monitor (WAM) in a energy  
range from
  50 keV to 5 MeV at 02:43:09.50 UT (=T0).

The observed light curve shows a multi-peaked structure, starting at
T0 s and ending at T0+7s, with a total duration (T90) of 6.5 s.
The fluence in 100 - 1000 keV was 6.22(+0.48,-0.42) x 10-6 erg/cm^2.
The 1-s peak flux measured from T0+1 s was 9.91(+0.89,-1.03) photons/s/ 
in the same energy range.

Preliminary result shows that the time-averaged spectrum from
T0-1s  to T0+7s is well fitted by a single power-law with
a photon index of 2.50 (+0.24,-0.22) (chi^2/d.o.f = 11.7/8).
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:
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