Detection of CO(J = 1-0) emission from barred spiral galaxies at z ∼ 0.1

We present the results of CO(J = 1-0) observations toward nine barred spiral galaxies at z = 0.08-0.25 using the 45m telescope at Nobeyama Radio Observatory. This survey is the first one specializing in barred spiral galaxies in this redshift range. We detected CO emission in six galaxies out of nine, whose CO luminosities (L′CO) ranged (1.09-10.8) × 10⁹ Kkms^-1 pc². These six are the infrared dimmest galaxies that have ever been detected in CO at z ∼ 0.1 to date. They follow the L0CO-LIR (IR luminosity) relation among such galaxies as local spiral galaxies, luminous infrared galaxies, ultra-luminous infrared galaxies, and submillimeter galaxies. Their L′CO and LIR are higher than those of local spiral galaxies, which have been detected in CO so far; LIR=L′CO, which is a measure of the star-formation efficiency, is comparable to, or slightly higher than, that of local ones. This result suggests that these six galaxies are forming stars more actively than local spiral galaxies simply because they have more fuel.