GCN Circular 12705
Subject
GRB 111215B: Suzaku WAM observation of the prompt emission
Date
2011-12-20T06:18:49Z (12 years ago)
From
Makoto Tashiro at Saitama U/Swift <tashiro@phy.saitama-u.ac.jp>
W. Iwakiri, M. Tashiro, Y. Terada, T. Yasuda, K. Takahara, M. Asahina,
S. Kobayashi, A. Sakamoto (Saitama U.) Y. Hanabata, T. Uehara, T.
Kawano, K. Takaki, M. Mizuno, M. Ohno, Y. Fukazawa (Hiroshima U.), S.
Sugita (Nagoya U.), K. Yamaoka (Aoyama Gakuin U.), M. Kokubun, T.
Takahashi (ISAS/JAXA), Y. E. Nakagawa (Waseda U.), N. Ohmori, M.
Akiyama, M. Yamauchi (Univ. of Miyazaki), C-J. Chuang, Y. Urata, P. Tsai
(NCU), K. Nakazawa, K. Makishima (Univ. of Tokyo),
The long bright GRB 111215B (localized by IPN: Hurley et al., GCN 12698)
triggered the Suzaku Wide-band All-sky Monitor (WAM) which covers an
energy range of 50 keV - 5 MeV at 20:28:05.704 UT (=T0).
The observed light curve shows a multi-peaked structure starting at
T0-0.5 s, followed by a long weak tail seen up to T0+75 s with a
duration (T90) of about 61 seconds. The fluence in 100 - 1000 keV was
2.81(-0.06, +0.09) x 10^-5 erg/cm^2.
The 1-s peak flux measured from T0+13 s was
8.68 (-0.52, +0.36) photons/cm^2/s in the same energy range.
Preliminary result shows that the time-averaged spectrum from T0-0.5 s
to T0+74.5 s is well fitted by a single power-law with a photon index of
2.05 (-0.06, +0.07) (chi^2 / d.o.f = 19.7/25).
All the quoted errors are at statistical 90% confidence level, in which
the systematic uncertainties are not included.
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