{
  "bibcode": "2009GCN..8908....1H",
  "body": "Y. Hanabata, Y. Fukazawa, T. Takahashi, T. Uehara, C. Kira (HiroshimaU.),\nY. Terada, M. Tashiro, Y. Urata, A. Endo, K. Onda, N. Kodaka,\nK. Morigami, T. Sugasahara, W. Iwakiri (Saitama U.), M. Ohno,\nM. Kokubun, M. Suzuki, T. Takahashi (ISAS/JAXA), K. Yamaoka,\nS. Sugita (Aoyama Gakuin U.), T. Enoto, K. Nakazawa, K. Makishima\n(Univ. of Tokyo), Y.E. Nakagawa, T. Tamagawa (RIKEN),\nE. Sonoda, M. Yamauchi, H. Tanaka, R. Hara, N. Ohmori, K. Kono,\nH. Hayashi (Univ. of Miyazaki), S. Hong (Nihon U.),\nN. Vasquez (Tokyo Tech), on behalf of the Suzaku WAM team, report:\n\nThe bright, long Fermi-LAT detected GRB 090217 (Fermi-GBM\ntrigger #256539404 ; von Kielin et al., GCN 8902;\nFermi-LAT detection ; Ohno et al., ; GCN 8903)\ntriggered the Suzaku Wide-band  All-sky Monitor (WAM) which covers an\nenergy range of 50 keV - 5 MeV at 04:56:42.98 UT (=T0).\nThe observed light curve shows a multi-peaked structure\nstarting at T0-3s, ending at T0+19s with a duration\n(T90) of about 14 seconds. The fluence in 100 - 1000 keV\nwas 1.56(+0.05,-0.09)x10^-5 erg/cm^2.  The 1-s peak flux measured\nfrom T0+7s was 3.0 (+0.2,-0.3) photons/cm^2/s in the same  energy range.\nPreliminary result shows that the time-averaged spectrum from\nT0-3s to T0+20s is well fitted by a power-law with exponential cutoff model:\n\n dN/dE ~  E^{-alpha} * exp(-(2-alpha)*E/Epeak) with\n alpha       0.81(+0.26,-0.31), and\n Epeak       780(+187,-126) keV (chi^2/d.o.f. = 41.0/24).\n\nThe GRB Band model also gives a good fit with only\nan upper limit on the high-energy photon index as follows:\n\nthe low-energy photon index alpha: -0.75(+0.50,-0.28),\nthe high-energy photon index beta: < -2.33,\nand the peak energy Epeak: 748(+195,-175) keV (chi^2/d.o.f = 40.4/23).\n\nPlease note that this GRB comes from the WAM 2 on-axis direction, which\nhas a large uncertaintiy only in absolute flux.\nAll the quoted errors are at statistical 90% confidence level,\nin which the systematic uncertainties are not included.\n\nThe light curves for this burst will be available soon at:\n\nhttp://www.astro.isas.jaxa.jp/suzaku/HXD-WAM/WAM-GRB/grb/trig/grb_table.html",
  "circularId": 8908,
  "createdOn": 1235019352000,
  "email": "hanabata@hep01.hepl.hiroshima-u.ac.jp",
  "subject": "GRB 090217: Suzaku WAM observation of the prompt emission",
  "submitter": "Yoshitaka Hanabata at Hiroshima U  <hanabata@hep01.hepl.hiroshima-u.ac.jp>",
  "eventId": "GRB 090217"
}