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   PR # 41205
   Ultra luminous FIR galaxies (hereafter ULFIRGs) have high luminoity
   of L>1E12Lo, which is comparable to that of QSO. Images of the
   ULFIRGs show that nearly all are strongly interacting merger system.
   Sanders et al. (1988) proposed an evolutionary connection between
   ULFIRGs and QSO. In their model, ULFIRG has a buried nucleus under a
   circumnuclear dust. The activity of nucleus will dominate, decaying
   starburst activity, then it becomes optically selected QSO. We would
   like to investigate the transition between ULFIRG and QSO. In recent,
   galaxy interaction can be well demonstrated with a computer
   simulation, with which the age can be estimated, comparing the
   simulation with observations. We select two ULFIRGs with diffrent
   stage of interacting merger.
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