[vsnet-grb-info 4863] GRB 070626: Suzaku/WAM observation of the prompt emission

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  6593
SUBJECT: GRB 070626: Suzaku/WAM observation of the prompt emission
DATE:    07/07/04 13:48:52 GMT
FROM:    Kazutaka Yamaoka at Aoyama Gakuin U  <yamaoka at phys.aoyama.ac.jp>

Y. Terada, T. Tamagawa (RIKEN), M. Ohno, T. Uehara, T. Takahashi, 
Y. Fukazawa, C. Kira (Hiroshima U.), K. Yamaoka, Y. E. Nakagawa, 
S. Sugita (Aoyama Gakuin U.), K. Morigami, N. Kodaka, K. Onda, 
M. Tashiro, M. Suzuki, Y. Urata, A. Endo (Saitama U.), T. Enoto, 
R. Miyawaki, K. Nakazawa, K. Makishima (Univ. of Tokyo), E. Sonoda, 
M. Yamauchi, S. Maeno, H. Tanaka, R. Hara (Univ. of Miyazaki), 
M. Kokubun, M. Suzuki, T. Takahashi (ISAS/JAXA), S. Hong (Nihon U.), 
on behalf of the Suzaku WAM team, report:

The long burst, GRB 070626 (S. Golenetskii et al. GCN 6592) was
detected at 2007-06-26 04:07:30 UT (= T0) with the Suzaku Wide-band All-sky
Monitor (WAM), which covers an energy range of 50 keV - 5 MeV. The burst
continues from T= T0-120 sec to T0+210 sec, as already reported on GCN
6592. The object position reported by GCN 6592 corresponds to the
incident angle of (theta, phi) = (103 deg, 169 deg) to the HXD WAM,
where the energy response is well calibrated. 
The fluence in the 100 -- 1000 keV energy band was 2.25(+- 0.01) x
10^-4 erg/cm2, and the 1-sec peak flux was 19.5 +/- 0.2 photons/cm^2/sec 
in the same energy range.

According to preliminary analyses, the time averaged spectrum from T0
to T0+190 sec in the 120 keV to 2.0 MeV energy band can be reproduced by 
the Band function (Band et al. 1993, ApJ 413, p281) with the following 
parameters;
  alpha = -1.55 +/- 0.05, 
  beta  = -2.15 +/- 0.05, and
  Epeak =   600 +/- 50 keV.

All the quoted errors are at the 90% confidence level, while systematic 
errors are not included. Since the on-board trigger system was disabled 
at the time of T0, no BST mode data with a time resolution of 15.625
msec is available, and the spectral analyses were performed by the 
continuous monitoring (TRN) data with the 1 sec resolution.

The light curve data with 1 sec resolution will be appeared at the web site 
 http://www.astro.isas.ac.jp/suzaku/HXD-WAM/WAM-GRB/grb/untrig/grb_table.html