Spectral Cross-calibration of the Konus-Wind, the Suzaku/WAM, and the Swift/BAT Data using Gamma-Ray Bursts

摘要

We report on the spectral cross-calibration results of the Konus-Wind, theSuzaku/WAM, and the Swift/BAT instruments using simultaneously observedgamma-ray bursts (GRBs). This is the first attempt to use simultaneouslyobserved GRBs as a spectral calibration source to understand systematicproblems among the instruments. Based on these joint spectral fits, we findthat 1) although a constant factor (a normalization factor) agrees within 20%among the instruments, the BAT constant factor shows a systematically smallervalue by 10-20% compared to that of Konus-Wind, 2) there is a systematic trendthat the low-energy photon index becomes steeper by 0.1-0.2 and Epeak becomessystematically higher by 10-20% when including the BAT data in the joint fits,and 3) the high-energy photon index agrees within 0.2 among the instruments.Our results show that cross-calibration based on joint spectral analysis is animportant step to understanding the instrumental effects which could beaffecting the scientific results from the GRB prompt emission data.