A Molecular Gas Survey of Z < 0.2 Infrared Excess, Optical Qsos

Millimeter-wave (CO) observations of optically-selected QSOs are potentially a powerful tool for studying the properties of both the QSOs and their host galaxies. We summarize here a recent molecular gas survey of z < 0.17 optical QSOs with infrared (IR) excess, LIR(8 − 1000μm)/Lbbb(0.1 − 1.0μm) > 0.36. Eight of these QSOs have been detected to date in CO(1 → 0), and the derived molecular gas masses are in the range 1.7−35×10 M⊙. The high LIR/L ′ CO of QSOs relative to the bulk of the local (z < 0.2) IR luminous galaxy merger population is indicative of significant heating of dust (LIR) by the QSO nucleus and/or by massive stars created in the host galaxy with high efficiency (i.e., per unit molecular gas, L′CO).