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   PR # 41203
   QSO is the luminous object in the universe, and its luminosity is
   about 1E+12Lo. The formation of QSO is still unknown. Sanders et
   al.(1988) proposed an atractive scenario to make QSO through the
   observations of ultra luminous FIR galaxies (hereafter ULFIRGs). In
   their scenario, the ULFIRGs will be in a transition phase to QSO, and
   luminous nuclei should be buried under a circumnuclear dust. Here we
   propose the ASCA observations of ULFIRGs, particulary WARM ULFIRGs in
   order to find the obscured nuclei in the galaxies. The ASCA is the
   best instruments to reveal the AGN activity behind the dust. Then we
   will discuss about the QSO formation.
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