Kana MATSUI
(Nobeyama Radio Observatory)
We are conducting CO observations of disk galaxies at z~0.1-0.2 with the two-beams receiver "TZ" of the 45-m telescope at the Nobeyama Radio Observatory. Only optical data were used to select samples with no help of infrared data which have been predominantly utilized to estimate CO fluxes of galaxies.
We will present preliminary results of the observations and discuss about the evolution of the gas fraction of disk galaxies which are expected to be at the stage of shaping their structures such as bars and arms.