CO Observations of Luminous IR Galaxies at Intermediate Redshift

We present new measurement of ${}^{12}$CO($J=1-0$) emission from 16 luminous infrared galaxies (LIGs) at intermediate redshift ($cz \sim 10,000 - 50,000 {\rm km s^{-1}}$). These new data were selected by isolated and normal morphology. The CO observations were performed using the NRO 45-m telescope. Comparison of the CO and dust properties of the new result with those from other CO measurements revealed characteristics of this sample: (1) It is the deepest CO observations of IRAS galaxies at intermediate redshift without strong interaction features. (2) It has typical properties of normal IRAS galaxies in terms of star-formation efficiency, color-color diagrams and galactic nuclear activity. (3) It has smaller gas-to-dust ratio than normal IRAS galaxies. This can be explained by two-component dust model, and our sample consists of most of warm dust.