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Description
One of the most prominent, yet controversial associations derived from the ensemble of prompt-phase observations of gamma-ray bursts (GRBs) is the apparent correlation in the source frame between the peak energy (E_peak_) of the {nu}F({nu}) spectrum and the isotropic radiated energy, E_iso_. Since most GRBs have E_peak_ above the energy range (15-150keV) of the Burst Alert Telescope (BAT) on Swift, determining accurate E_peak_ values for large numbers of Swift bursts has been difficult. However, by combining data from Swift/BAT and the Suzaku Wide-band All-Sky Monitor (WAM), which covers the energy range from 50 to 5000keV, for bursts which are simultaneously detected, one can accurately fit E_peak_ and E_iso_ and test the relationship between them for the Swift sample. Between the launch of Suzaku in 2005 July and the end of 2009 April, there were 48 GRBs that triggered both Swift/BAT and WAM, and an additional 48 bursts that triggered Swift and were detected by WAM, but did not trigger. A BAT-WAM team has cross-calibrated the two instruments using GRBs, and we are now able to perform joint fits on these bursts to determine their spectral parameters. For those bursts with spectroscopic redshifts, we can also calculate the isotropic energy. Here, we present the results of joint Swift/BAT-Suzaku/WAM spectral fits for 91 of the bursts detected by the two instruments.
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